Beginners Guide to Overclocking nVidia Video Cards

There are a lot of folks out there that love nVidia based video cards for the stunning performance they provide and continue to deliver with each new product release. But what video card would be complete without at least some overclocking to boost performance even more, without spending a single cent... Today Nick Swan shows us just how we can increase the performance of our nVidia based cards in this beginners guide to overclocking nVidia video cards.
TweakTown Staff
Published Thu, May 23 2002 11:00 PM CDT   |   Updated Tue, Apr 7 2020 12:25 PM CDT
Manufacturer: none

Video Card Overclocking Guide - Introduction

IntroductionThere isn't much to introduce in a guide like this, but I'll tell you what's in this guide nevertheless. The two programs I used to overclock my video card were NVmax and Coolbits. Unfortunately, NVmax has become an unsupported product recently, but it still remains an extremely powerful tool. Coolbits on the other hand is nowhere near as powerful as NVmax, but at least it remains supported.Anyway, in the guide I look at the simple overclocking in Coolbits and NVmax, and the much more complicated, and rather useful, extra features of NVmax. After that, we take a brief look at the BIOS and cooling and a few of the problems related to overclocking.On with the show, lets take a look at what overclocking is.

Video Card Overclocking Guide - Common Questions

What is Overclocking?To put it very simply, overclocking is making your computer, or a certain component, run faster than the manufacturer set it to when it left the factory.Why should I overclock my computer?Again, to put it simply, the idea behind overclocking your computer is to get a free performance increase. The processes involved in overclocking are now very simple, and more speed is literally at your fingertips. A while ago, overclocking was limited to just increasing the CPU speed, but now there are a myriad of options to alter in the quest for more speed. One of the best ways to obtain more speed is through video card overclocking, and even small adjustments to the speed of the card can give reasonable frame rate increases.What are the problems associated with overclocking?There are three main problems associated with overclocking, and two of these can be removed if you are sensible in undertaking the overclocking. The first of these is the most serious in many people's minds, and is the one that can't be eliminated. By overclocking your video card, you are actually voiding the warranty supplied by the manufacturer. The second problem associated with overclocking, both with CPU's and with video cards, is heat. If your computer is too hot, it either won't work properly, or won't work at all. Thankfully this problem is easily fixed, and this guide looks at cooling in a bit of detail. The third problem associated with overclocking video cards are things called artifacts. They are weird graphical glitches which signify you have a serious problem. Again, these can easily be fixed.

Video Card Overclocking Guide - My Video Card

My Video CardBefore we look at overclocking, I should point out what I am using, so you can compare results and see why your card has/has not got features mine does, especially with Anti-Aliasing and filtering methods.The video card I own is a Hercules GeForce3 Ti200. The card is very close to the nVidia reference design, which isn't necessarily a bad thing, but does mean it's fairly feature thin. The stats of the card are:Core: nVidia GeForce3 Ti200 Core, 0.15 micron, 175MHzRAM: 4.0ns DDR SDRAM, 400MHz, 128-bit DDRBus: AGP 4x with Fast WritesCooling:Core - Half size Blue OrbMemory - Blue HeatsinksOthers: TV-OutAs you can see, the card is certainly a standard, non-variation version. One thing Hercules has opted for is non-stock cooling. They have added a half sized Blue Orb and some RAM sinks. The RAM sinks are more than likely Thermaltake ones, as they look exactly the same including color and the chipset cooler is a Thermaltake product, so the heatsinks probably are too. On my card I replaced the chipset cooler with a full sized Blue Orb, which will help to overclock the core slightly higher. I'll explain how to fit a new cooler a little later.

Video Card Overclocking Guide - The BIOS

BIOSBefore we even enter Windows, a few small tweaks can be carried out to improve your graphical performance. Even though they won't give the performance increases that overclocking will give, they are worthwhile and very easy to carry out.AGP Aperture SizeThis number, measured in MB, represents how much of your system memory is available to the video card. This allows the video card to use data in the system memory instead of its own memory, and it allows textures to be stored in the system memory when they cannot fit in the video cards own memory. Obviously you need to set this effectively, or you will lose graphics performance, or even general system performance. Try one of the following settings, and then set it on whichever gives you the best performance.If you have 256MB of RAM or less, set the AGP aperture size to either 1/4 or 1/2 of your system memory, i.e. 256MB computers should set it at 64MB or 128MB. If you have more than 256MB of RAM, you should try and set it at 1/3 or 1/4.AGP ModeThe PCI bus speed is 33MHz which allows for a maximum data throughput of 133MB/s. While that seems like an impressive number, it actually doesn't give anywhere near the bandwidth needed for applications like 3D games. The AGP bus went some way to change this. The original AGP (1x) had a 66MHz bus speed, which gave maximum bandwidth of 266MB/s. This was then updated to AGP 2x, which gave 533MB/s, and AGP 4x, which gives 1GB/s. The faster bus your video card can handle the better, as more data can be moved in the time period. All new video cards are AGP 4x, but older cards are 2x and even 1x. Set your card to its maximum setting. You should have no stability issues, and you will allow the video card its maximum bandwidth possible. Owners of GeForce 256 card may find they have problems running AGP 2x on VIA chipsets and are thus forced to run it at 1x. If you look around, you can find programs to overcome this problem.AGP VoltageWhen you increase this, you are increasing the voltage that is being sent to the core of your video card. The purpose of this is to try and get the core to run faster than possible when at a voltage setting. The main drawback to raising the voltage is the increased heat output from the core. If your cooling setup cannot handle the increased heat, the card will do anything from producing artifacts, crashing, or not booting up at all, or a combination of the first two. If you can raise the voltage without heat affecting the performance, you can bring very good increases in overclocking potential to the card.Note: This does the same thing as raising the CPU/DIMM voltage, but obviously effects a different device.Raising the Core Voltage can also result in your hardware having a shorter lifespan and a significantly shorter warranty, so be careful.

Video Card Overclocking Guide - NVmax and Coolbits

NVmax and CoolbitsThe easiest and simplest way to overclock your video card is through an application in Windows. These will also give you the best speed gains compared to the BIOS and other methods by a long, long way. The two main utilities used to overclock nVidia graphics cards are the program 'NVmax', and the registry hack 'Coolbits'. While these two offer the same basic tweaking, that of the core and memory, NVmax also offers a myriad of options from filtering to general refresh rates. Thus NVmax is far more powerful, but Coolbits still gets the job done. Obviously the best place to start is to download one of these programs. The choice is yours, but I'll explain what to do for both versions, so get both if you feel like it and experiment to find what's best for you.To download Coolbits, go to this URLTo download NVmax, go to this URL

Video Card Overclocking Guide - Installing NVmax and Coolbits

Installation Tips?You're probably wondering why I am telling you how to install such a basic program. If you're asking this, I would assume you know how to, but to some people, installing things is a major event that is scrutinized very carefully. Even more concern occurs when Coolbits asks if you want to make a new entry into the registry. To many people, Registry = No-Go.InstallationNVmax first - Unzip the file if it came zipped and then run the file called NVmax.exe - how nice of them to name it that. When you have executed the file, it will act like a normal installation and then open the program once you're in there. Very easy.Coolbits is just as easy, but the area you tweak from is a maze to get to. After you have downloaded it, run the file and say "yes" to the question about adding the information from the Coolbits file to the registry. This will not, OK, shouldn't, do anything bad to your system. The notion that fiddling with the registry is a no-no, is completely and utterly wrong if you do things the right way, following the instructions.

Video Card Overclocking Guide - Overclocking with Coolbits

Getting into CoolbitsYes, it sounds absurd, but actually getting into Coolbits is harder than overclocking with Coolbits... To get to the Coolbits overclocking utility, you need to open the display properties by right clicking on your desktop. Then you will need to select the Settings tab, and click on Advanced. It should bring up a screen like this:
Once you're at this point, you will need to click on the tab that has the name of your video card. In my case, it says GeForce3 Ti200. Once you have selected your card's tab, a window like this will appear.
At this point, select the Advanced Properties tab located at the bottom of the window. Once that is selected, this window should appear:
From here, select the Clock Frequencies tab, and you can go onto the next stage.Overclocking with CoolbitsOverclocking your video card is a lot easier than you would expect, and if you can manage the maze of tabs to get into Coolbits, then you will be able to work out what you're doing very easily. Once you have entered the Clock Settings tab of the Display Properties, all you have to do is select what frequency you want your core and memory to be running at. This is done by moving the sliding tab to the corresponding position, rather easy...The first picture shows Coolbits with my card at its default settings, 175MHz/400MHz:
The next picture is my card running at its new standard speed of 190MHz/435MHz. This change was made by sliding the frequency bar.
The last picture is the max settings Coolbits will allow for my Ti200. While the settings of 215MHz core and 500MHz memory are far above the standard speed, it would be nice to be able to set these higher as my card does higher than this while running stable. To obtain a higher core/memory speed, I'll have to use NVmax.
As you can see, Coolbits is extremely easy to use. Once you have the desired speed, select "Test New Setting" tab, click "Apply" and if all is well, you have just overclocked your video card. Go and test these settings in a game or 3DMark and if no glitches are present, you can try higher or select "Apply these settings at restart" which will make the new speeds the default once you have restarted.

Video Card Overclocking Guide - Overclocking with NVmax

NVmax is a significantly more powerful tool than Coolbits, so be careful and don't change things you don't know the purpose of. However, the key terms/options will be explained a little later, but I'll look at NVmax's overclocking first.Overclocking with NVmaxThere are a lot of other options in NVmax to fiddle with, but for now we will skip past them and focus on the Core/Memory overclocking part of the application. Once you have opened NVmax, go to the icon that looks like a pair of cogs, and select it. The first thing you will notice is the much larger range of frequencies NVmax offers. I can set my GeForce3 at 275/640MHz, which is obviously far past the limits of the card. Thus the extra frequencies NVmax offers are basically a waste of time, but I can set my card to around 510MHz memory, which is the maximum overclock obtainable without artifacts, and which was unattainable using Coolbits.The overclocking with NVmax is just as easy as Coolbits. To change the speeds, simply move the slider corresponding to Core/Memory to the desired speed. A five second timer will then start, and if you have not clicked the mouse, the card frequencies will change to your setting. If you have moved the slider too far and can't get it to the right spot, clicking on the countdown message will reset to the previous value.Another thing to note is the recommended frequency zone that NVmax gives. This is represented by a blue bar in the speed bars. You may as well ignore this, as my recommended memory speed is about 362-422MHz which is below and just above to the standard clock speed of the card. Unless you have a really low quality Ti200, you will easily be able to pass 422MHz on the memory. The same goes for the core recommendation, this time ranging from 145-188MHz.

Video Card Overclocking Guide - The other NVmax options

NVmax's other optionsWhile NVmax serves its overclocking purpose very well, there are numerous other options it provides you with to tweak. While some are basically useless, others will have a decent impact on your system performance. This is a list of some of the main, non-overclocking options provided in NVmax.D3D - Because NVmax likes to split the tweaks into two sections, D3D and OpenGL, I shall do the same!Anti-Aliasing - Basically, this removes the jagged edges on an object when it is shown on your monitor. While it does make the picture look clearer, it unfortunately causes a significant performance hit, especially when using 4 sample AA. For the best possible performance you should set this to Off, but if your card can handle higher without problems, it's a nice option to have on. The auto option here lets the program decide whether to use AA, and if so, what level. Note: Not all cards support AA. Some cards will also support different types of AA, which others don't. For example, GeForce3's support Quincunx, while the GeForce4 supports 4xS, which no other card supports. The Voodoo 5 6000, although unreleased, was suppose to support 8x AA!Anisotropic Filtering - Basically, anisotropic filtering reduces the blurriness associated with certain filtering methods like bilinear and trilinear filtering. This boils down to making things like writing less blurry and easier to read. Like Anti-aliasing, selecting a higher level of anisotropic filtering will lower your performance but give better visuals. You may as well turn this option to auto and let the program decide for you. If your card has performance to spare, try fiddling with the levels of filtering to find the one that has the best performance/looks ratio. Similarly to Anti-Aliasing, different cards support different levels, and some don't support anisotropic filtering. The GeForce3 was the first card to support it.Texture Compression - Texture compression in your video card works just like a jpeg or gif bitmap. The texture is reduced in size numerous times which allows more textures to be stored and sent at once. However, like jpeg's and gif's, artifacts will affect the texture after compression and it ends up looking worse than before. Leave this turned on (don't select the disable texture compression) as it can improve graphical performance quite reasonably. However, it can make games look significantly worse, so test it and see if you prefer it off or on.V-Sync - This option lets you decide whether the maximum number of frames per second is equal to the maximum refresh rate of your monitor in the resolution you are running. There is no real harm in turning this option to "off" as the effects of having more frames than your monitor can handle are rarely noticed and don't do anything bad to your hardware.OpenGL, Anisotropic Filtering and Anti-Aliasing - The same as above applies here.Force S3TC v3 Compression - This is a form of texture compression developed by S3. It works in a similar manner to the one described above. If you are looking for plain performance, you should turn this on, but if you're after visuals, turn this off.

Video Card Overclocking Guide - Cooling

CoolingThe HSF (Heat Sink/Fan) that comes with many video cards, as well as a lot of CPU's, are only sufficient to cool the component at the stock speed, and occasionally you even see some that don't work properly at default speeds! When components become overclocked, they produce more heat and the default coolers wave small white flags in the air surrendering. The solution to this rather annoying problem is to buy better cooling equipment.In the CPU market, there are hundreds of coolers to choose from with choices ranging from fan size and speed to the material the heat sink is made from. Unfortunately, the video card cooling market is a lot smaller, and basically consists of one company. That company is Thermaltake, who makes the Blue Orb and Crystal Orb. The other option people have is water cooling, but that is reasonably hard to implement and is impractical in most places.Core CoolingThe only real options here are the Thermaltake Blue Orb and Crystal Orb (you can go water cooling here, but i doubt you will want to). The two Thermaltake products look like this:
This is the Crystal Orb. Not exactly crystal, but at least it's silver.
This is the Blue Orb. If you want to know more about these products, then go to the manufacturer's webpage.The cooler to buy is, without question, the Crystal Orb. The Crystal Orb is made of copper, instead of aluminum as is used in the Blue Orb. Copper is regarded as a better material to make heatsinks from, as it conducts heat far better than aluminum does. However, the Blue Orb still does its required job very well. One thing to remember is that both these coolers are 5500RPM models so they don't sound like your PC is ready to take off.The installation of a new cooler is a reasonable easy affair, so don't worry. If you want to fit one, try these steps:(1) - Take the old cooler off. If it is joined by push pins, squeeze the end bit on the back side of the card and then push the pin up and the cooler should come loose. The material between the cooler and core can play an important role here. If the material is thermal paste, like Arctic Silver, then you will likely have push pins, and the cooler will come off with the step above. However, if your cooler is connected through thermal tape, you're in a spot of bother. These can be really hard to get off. The most common way to get this stuff off is to use a knife or similar object and pry the cooler from the tape. I have also heard that putting it in the freezer and similarly crazy techniques that can work to get it off. Be warned though, using a knife to pry the cooler of can obviously damage your card. Thermal epoxy is another method of keeping coolers on cards and this one sure doesn't come off easily. You may as well get a different card if yours is connected using this method. Why? You will most likely destroy the card in the process of taking it off.(2) - Once you have the old cooler off, apply a thin layer of thermal paste, like Arctic Silver (recommended), over the core. The thermal paste is intended to fill tiny gaps between the core and the base of the cooler so you don't need to spread this stuff like your making a sandwich. If you're not using thermal paste, go to 4.(3) - When the thermal paste has been applied, place the cooler onto the core, and push the pins through the holes. These should not come back out, but if they do, check for broken pins and that you are doing it the right way. Go to 5.(4) - If you're connecting with thermal tape, simply stick this onto the base of the cooler, and stick it onto the core.(5) - Once the cooler is attached, you will need to join the fan power cord to a fan header. Join it to any header, but if you want to monitor the fan speed, make sure you join it to a header that supports this. Another option is buying a 3-4 Pin adapter which can lessen the stress on the motherboard, but a 5500RPM fan shouldn't cause much of a problem.

Video Card Overclocking Guide - Problems

Problems with overclockingHeat: It's an overclockers worst enemy. The excess heat that overclocking your video card produces can not only affect your visuals with artifacts, or no picture at all, but also CPU overclocking. The reverse is also true when overclocking your CPU. Artifacts are strange graphical glitches that occur when you overclock your video card too far. These can range from missing pixels and textures to weird lines running across the screen. If you can see these when you have overclocked your video card, you have a problem! Fortunately, there is an easy fix. Simply move back your memory/core speeds until the artifacts go away. If you ignore the artifacts, you run the risk of permanently damaging your video card.As I stated, the main reason behind this is heat. Apart from installing heatsinks and coolers to your card, which is detailed above, try to increase the airflow around your graphics card. A system exhaust fan over a PCI slot which vents hot air out of the case that would otherwise linger around the graphics card is an excellent way to reduce case temperatures and thus graphics card temperatures. You can also try to set up a fan that blows cool air into the graphics card area which should also give a reasonable increase in cooling.

Video Card Overclocking Guide - Results

Results - Everyone's favoritePutting everything written here into practice, we can see what types of gains can be made from overclocking. Please remember, these gains will differ from person to person, so if I score an increase way more/less than yours, don't be concerned.The first thing I should mention is my computer specs, which are:AMD Athlon XP 1600+Thermaltake Volcano 6Cu+Soltek 75DRV-2 Mobo256MB Kingmax PC2100 DDR RAMHercules GeForce3 Ti200Seagate Barracuda IV 40GB HDDSB:Live 5.1 DEA Laser Mouse!Win 98SE (I still can't part with it....)And other stuff that's irrelevant.The drivers that I used in these tests were Detonator v23.11. My CPU was overclocked to 1478MHz, which isn't that much but it allowed me to raise the FSB to 140MHz. This gives slightly more bandwidth to the processor, which is important, as the bandwidth is the limiting factor for AMD chips at the present moment. Now for results.The best program to test overclocking gains is probably 3Dmark2001SE, which tests basically all video card functions, including new DirectX 8.1 functions (which only Radeon 8500 and GeForce3/4's support). This doesn't test real-world gains like Quake III and Serious Sam, but it gives an excellent overview of general gains.
The first thing to note here is the different memory speeds listed. The top speed, 235/495, was completely stable, but above that proved to be erratic at times, and I thus decided to keep 235/495 as the top speed. Remember that is only 5MHz core and memory, from the GeForce3 Ti500 speeds, so it still gives an excellent representation of what a Ti500 does.Overall, I managed to gain approximately 1000 3DMarks from the video card by overclocking. This came through a core increase of 60MHz and a Memory increase of 95MHz. When looking at the performance increases from overclocking the memory, you can equate it back to an equation which gives the maximum possible bandwidth the card can provide. The maximum possible bandwidth is, like the name suggests, the maximum amount of data the cards memory can move in a prescribed time, in this case, and most cases, one second. The equation is:Memory Bandwidth = Memory bus width * memory speed / 8The memory speed here is the actual speed it is running at, which means 200MHz DDR RAM would be included in the formula as 400MHz (since that is the speed it runs at). The memory bus width is measured in bits. The GeForce3's bus is 128-bit DDR. By adding the numbers in, you get:128 * 400 / 8 = 6400MB/sAnd that is the memory bandwidth of the card when running at stock speed. 6400MB/s looks like a VERY impressive number, but in reality it isn't brilliant. The GeForce4 Ti4600 has much a higher 10400MB/s, which is part of the reason it is so much faster. In most cases, increasing the memory bandwidth will increase the performance of the card. To increase the bandwidth, you raise the memory speed. By moving the memory speed a modest 20MHz, to 420MHz, we now have a memory bandwidth of 6720MB/s. This increase certainly doesn't set the world on fire, but it will help slightly. Moving the memory to the GeForce3 default speed we get a bandwidth of 7360MB/s. This is now 1000MB/s more, which is quite significant and means 1000MB more can be moved each second.One thing to note is that this card, along with most good Ti200's, comes with 4ns RAM. 4ns RAM is actually rated to run at 500MHz. This can be seen using the very simple formula:RAM Speed = 1000 / nsSo: RAM speed = 1000 / 4ns =500MHz (the speed at which the GeForce3 Ti500's memory runs, but that card uses 3.8ns memory). If we could run the memory at 500MHz, we could boost our memory bandwidth significantly.Bandwidth = 128 * 500 / 8 = 8000MB/s8000MB/s is a very handy 1600MB/s increase over the memory bandwidth of the card at its stock speed. Unfortunately, having 4ns RAM doesn't guarantee you being able to run at 500MHz, but if you can't get to that speed, you can usually get close (~480MHz is common, which is still faster than the original GF3, which had 460MHz memory).There are also formula to calculate things like fill rates, triangles per second, pixels per second and so on. These are similar to the ones above and honestly don't mean anything. For example, by working out your fill rate and a few other numbers, you can work out your maximum possible FPS in a certain resolution. You will find you get very large numbers, which obviously are impossible to obtain in normal usage. Thus I have not added irrelevant numbers like that. I did include the memory bandwidth however, because it gives a decent indication of what overclocking does, and because memory overclocking does more for performance than core overclocking.Another interesting point that shows in these tests is that a certain percentage increase in speed doesn't make the scores increase by that same percentage. At the default GeForce3 Ti200 speed of 175/400, I scored around 6600 3DMarks. I then raised the memory and core speed by 10% (just over 10% in the cores case), and recorded a score of 6800 3DMarks, which certainly isn't a 10% increase in speed. In fact, it equates to a lowly 3% increase in speed.If we look at the percentage increase we get from overclocking the card 10% on just the memory, we can confirm that overclocking by a certain percentage really doesn't equate to that percent in performance gains. At 175/420, a 10% increase on the memory, I scored 6678 3DMarks. This is a measly 52 point increase. This pitiful increase may be due to benchmarking inconsistencies, but I am tending to believe not as other, large increases in speed have also given small 3DMark gains.So as we can see, a certain percentage increase in speed certainly doesn't mean you get that same increase in performance. I wish it did, but nevertheless a 23.75% increase in memory speed and a 34% increase in core speed did give a 1000 point increase in 3DMark2001SE (about 15%).

Video Card Overclocking Guide - Conclusion

ConclusionThere we have it. It is certainly not as difficult as you would think to overclock your video card, and the rewards are certainly rewarding if you can overclock far enough. If you're having problems with your overclocking, make sure you follow the steps exactly, and everything should be fine. Otherwise email me and I'll see what's wrong.Remember - Be sensible when you are overclocking as you certainly don't want to damage an expensive PCB. At any sign of danger, throttle back and go from there.

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