Intel Core i7 CPU Scaling with HD 6850 in Crossfire

You're not running 4.2GHz on a $1,000 CPU? That's cool - Let's see how this $400 VGA setup runs at different clock speeds.

Published
Updated
Manufacturer: Intel
7 minutes & 55 seconds read time

Introduction and Specifications


Introduction

Intel Core i7 CPU Scaling with HD 6850 in Crossfire 02


In our video card benchmarks we run a $1,000 980X at 4.2GHz and while we understand that it's not a CPU most people use, there's a logical reason behind it. When we benchmark cards we want to make sure that we don't hit a CPU limitation and limit the maximum performance of a possible setup.

So, to make sure that doesn't happen, we overclock our CPU as much as possible. Today, though, we're going to mix it up a bit. Instead of testing different video cards, we'll be looking at our 980X at a number of different speeds.

We've recently tested the HD 6850 in Crossfire and loved the performance it offers. What we love more, though, is the price. If you're paying out $400 for a video card setup the chances are you're not putting over double that on the CPU, which is something we completely understand.

So what we've done today is grabbed our 980X, disabled a couple of cores and started testing performance at a number of different speeds. Sure, more CPU is better; but how much better? - What kind of CPU should you be buying for a setup like the HD 6850 in Crossfire?

These are questions we're going to answer today. Let's have a closer look at our testbed and what exactly we've done before we get into the actual performance and see the CPU scaling effect on our video cards today.

Test System Setup and 3DMark Vantage


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We would like to thank the following companies for supplying and supporting us with our test system hardware and equipment: Intel, ASRock, Kingston, Mittoni, Noctua and Corsair.

What we've done today is clock our 980X to different speeds while disabling cores at times to simulate low priced and lower clocked CPUs. For example, we leave the BCLK at 133MHz, disable two cores and drop the multiplier down to 23 to give us a clock speed of 3.06GHz. This will help us simulate the performance of an i7 950.

While it's not perfect, as we've got a bit more L3 Cache on our 980X, the speed is going to be one of the most important factors in helping us judge the scaling benefits of higher end CPUs.

Apart from the highest clock speed, the BCLK has been left at 133 and only the Multiplier has been adjusted from 23 - 29.

Due to the amount of testing that had to be done, we've cut our benchmarks down slightly, but we've included all the important stuff including all the resolutions that we normally test at.

Let's get started!


3DMark Vantage

Version and / or Patch Used: 1.0.1
Developer Homepage: http://www.futuremark.com
Product Homepage: http://www.futuremark.com/products/3dmarkvantage/
Buy It Here




3DMark Vantage is the new industry standard PC gaming performance benchmark from Futuremark, newly designed for Windows Vista and DirectX10. It includes two new graphics tests, two new CPU tests, several new feature tests, and support for the latest hardware.

3DMark Vantage is based on a completely new rendering engine, developed specifically to take full advantage of DirectX10, the new graphics API from Microsoft.

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As we move the clocks up we see a little positive movement, but nothing major. The biggest gains are seen at 4.2GHz with all our cores enabled.

Unigine Heaven Benchmark




Version and / or Patch Used: 2
Developer Homepage: http://www.unigine.com
Product Homepage: http://unigine.com/press-releases/091022-heaven_benchmark//



New benchmark grants the power to unleash the DirectX 11 potential in the gift wrapping of impressively towering graphics capabilities. It reveals the enchanting magic of floating islands with a tiny village hidden in the cloudy skies. With the interactive mode emerging experience of exploring the intricate world is ensured within reach. Through its advanced renderer, Unigine is one of the first to set precedence in showcasing the art assets with tessellation, bringing compelling visual finesse, utilizing the technology to the full extend and exhibiting the possibilities of enriching 3D gaming.

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Across the board you can see that the extra MHz really does very little for more performance with nothing more than a bit of fluctuation being seen.

Benchmarks - Resident Evil 5


Resident Evil 5

Version and / or Patch Used: Demo Benchmark
Developer Homepage: www.residentevil.com/
Product Homepage: http://www.residentevil.com/




Resident Evil 5 is a survival horror video game developed and published by Capcom. The game is the seventh installment in the Resident Evil survival horror series, and was released on September 18. Resident Evil 5 revolves around Chris Redfield and Sheva Alomar as they investigate a terrorist threat in Kijuju, a fictional town in Africa.

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You can see, at 2560 x 1600 there's no CPU limitation; instead we're only limited by our video cards. At 1920 x 1200 and 1680 x 1050, though, there's a clear CPU limitation with the difference between the 3.06GHz clock and 4.2GHz one being extremely large.

Benchmarks - Lost Planet 2


Lost Planet 2

Version and / or Patch Used: Benchmark Demo
Timedemo or Level Used: Built in Benchmark - Test A Scene 1
Developer Homepage: http://www.capcom.com/
Product Homepage: http://www.lostplanet2game.com/




Lost Planet 2 is a third-person shooter video game developed and published by Capcom. The game is the sequel to Lost Planet: Extreme Condition which is also made by Capcom, taking place ten years after the events of the first game, on the same fictional planet. The story takes place back on E.D.N. III 10 years after the events of the first game. The snow has melted to reveal jungles and more tropical areas that have taken the place of more frozen regions. The plot begins with Mercenaries fighting against Jungle Pirates. After destroying a mine, the Mercenaries continue on to evacuate the area, in which a Category-G Akrid appears and attacks them. After being rescued, they find out their evacuation point (Where the Category-G appeared) was a set-up and no pick up team awaited them. The last words imply possible DLC additions to the game, "There's nothing to be gained by wiping out snow pirates... unless you had some kind of grudge."

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Lost Planet 2 across the board sees very similar performance from our VGA setup at all resolutions with nothing more than a bit of fluctuation being seen.

Benchmarks - Aliens vs. Predator


Aliens vs. Predator

Version and / or Patch Used: Standalone Benchmark
Timedemo or Level Used: Built in Benchmark
Developer Homepage: http://www.rebellion.co.uk/
Product Homepage: http://www.sega.com/games/aliens-vs-predator/




Aliens vs. Predator is a science fiction first-person shooter video game, developed by Rebellion Developments, the team behind the 1999 original PC game, and published by Sega for Microsoft Windows, the PlayStation 3 and the Xbox 360. The game is based on the Alien vs. Predator franchise, a combination of the characters and creatures of the Alien franchise and the Predator franchise. There are three campaigns in the game, one for each race/faction (the Predators, the Aliens and the Colonial Marines), that, while separate in terms of individual plot and gameplay, form one overarching storyline.

Following the storyline of the campaign modes comes the multiplayer aspect of the game. In this Multiplayer section of the game, players face off in various different gametypes in various different ways.

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AvP sees the same with no change across the board and the numbers being almost identical at all resolutions.

Benchmarks - Far Cry 2


Far Cry 2

Version and / or Patch Used: 1.01
Timedemo or Level Used: Ranch Long
Developer Homepage: http://www.ubi.com/
Product Homepage: http://www.farcry2.com/
Buy It Here




The Dunia Engine was built specifically for Far Cry 2 by the award-winning Ubisoft Montreal development team. It delivers the most realistic destructible environments, amazing special effects such as dynamic fire propagation and storm effects, real-time night-and-day cycle, dynamic music system, non-scripted enemy A.I. and so much more.

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Far Cry 2 sees more performance as we get more and more MHz. You can see the CPU limitation is very obvious at 1920 x 1200 and 1680 x 1050.

Benchmarks - Batman Arkham Asylum


Batman Arkham Asylum

Version and / or Patch Used: 1.1
Timedemo or Level Used: Built-in Test
Developer Homepage: http://www.batmanarkhamasylum.com/
Product Homepage: http://www.batmanarkhamasylum.com/





Batman: Arkham Asylum exposes players to a unique, dark and atmospheric adventure that takes them to the depths of Arkham Asylum - Gotham's psychiatric hospital for the criminally insane. Gamers will move in the shadows, instigate fear amongst their enemies and confront The Joker and Gotham City's most notorious villains who have taken over the asylum.

Using a wide range of Batman's gadgets and abilities, players will become the invisible predator and attempt to foil The Joker's demented scheme.
Batman: Arkham Asylum features an original story penned exclusively for the game by famous Batman author and five-time Emmy award winner Paul Dini, whose credits include Lost season one and Batman: The Animated Series.

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Here we again really see the CPU limitation that's present at all resolutions; especially when you look at the minimum numbers.

Benchmarks - High Quality AA and AF


High Quality AA and AF

Our high quality tests let us separate the men from the boys and the ladies from the girls. If the cards weren't struggling before they will start to now.

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With AA on, AvP sees very little difference. Far Cry 2 is a little different with a 10% difference being seen from 3.06GHz and 4.2GHz when looking at the minimums.

Final Thoughts




The CPU limitation issue is a very real one and can't be ignored. It's ignorant to think that even more budget friendly setups like the HD 6850 in Crossfire aren't going to be impacted by a CPU limitation, as at this price AMD really give us a huge amount of performance.

There's a few ways to combat a CPU limitation, though, and it's not by just increasing your CPU speed. The idea is that you want to put more load on the video cards and this can be done really in three ways. Up the in-game detail up higher than what it was at previously is one. If that's not an option, start to look at turning on AA and AF which really place a lot more pressure on your cards.

The final way is to increase the resolution you're gaming at, again, by placing more pressure on the video cards. You can clearly see with intensive games like Aliens vs. Predator the performance at 1920 x 1200 on our CPU at 3.06GHz is the same as it is at 4.2GHz while we're running more voltage through the CPU and possibly shortening the life. So what reason is there to overclock the CPU that high in this kind of a situation? There isn't one really.

When you really begin to break it down, though, the times we hit a CPU limitation we're already getting fantastic performance in games. Resident Evil 5 is a prime example. At 1680 x 1050 and our CPU at 3.06GHz we've got an average FPS of 178, while at 4.2GHz we've got an average FPS off 223.

Sure, that's a great gain, but that extra performance isn't going to make the game any better for you. Even in a situation where you're using a 120Hz monitor, you're at a number that's well and truly comfortable when at 3.06GHz.

I don't want to give the impression that buying a faster CPU is a waste of money, as we know that there's more to the purchase of a CPU than just gaming. But it's important to know that under situations where your video detail is high, the added speed of not just a few hundred MHz, but more than a GHz at time, can yield almost no performance increase when it comes to your actual FPS. Of course, as you climb up to higher end video card setups that come in at an excess of $1,000, then the more speed is going to be appreciated. That's something we may look at when the HD 6900 series begin to arrive.

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Shawn takes care of all of our video card reviews. From 2009, Shawn is also taking care of our memory reviews, and from May 2011, Shawn also takes care of our CPU, chipset and motherboard reviews. As of December 2011, Shawn is based out of Taipei, Taiwan.

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