Gigabyte has put some major emphasis on this board (being a premium line board) for the hardcore enthusiasts and with the layout of the board itself, you are sure to get this feeling. Although it is within the BIOS that defines the board for the overclockers who want extreme speed, and for that, you need a wide variety of voltage and clock frequency options to give that extra MHz overclock to make the board that much sweeter.
To locate the overclocking features in the Gigabyte BIOS, you need to navigate to the MB Intelligent Tweaker (M.I.T) menu. This is where you can overclock to your hearts content.
First off like previous Gigabyte boards, the G1 supports automatic overclocking by profile, Gigabyte calls it C.I.A.2. This allows the motherboards onboard logic to automatically raise the FSB and voltages by a pre-determined maximum percentage to allow you to gain some extra speed when the system is under heavy load.
For those who manage to afford a Pentium Extreme Edition CPU, you have the luxury of overclocking your CPU by multipliers. That's right, Intel leaves the multipliers on Extreme Edition CPU's open for users to do as they wish - we are guessing they took a page from AMD with the FX line of 64 bit processors. Gigabyte's BIOS detects this and if you are able to change the multiplier you are given access to this function. The options are dependant on CPU but most allow from 12x up to 60x. While 60x is a little optimistic, it's good to see that there are options here for you.
FSB adjustments are very generous. Gigabyte offers a range from 100MHz up to a maximum of 600MHz in 1MHz increments. Gigabyte is pushing this board for extreme overclocking and this is clearly evident with the FSB adjustments. While 600MHz on air isn't possible, add an extreme water cooler or Vapochill and see what happens.
PCI Express frequencies are extremely important. Settings that are provided are from 90MHz to 150MHz in 1MHz increments. Auto leaves the bus on external ratios, so if you plan to overclock, set this to 100MHz manually to keep the PCI Express bus at its default, which is your best move.
While most boards lock the PCI bus now to 33MHz, Gigabyte gives you this option so you know what is happening. Here you can leave it on auto which runs its on dividers, or physically lock it to 33MHz by selecting the option.
Next on the list is the memory ratio control. Since there are a wide variety of DDR-2 modules now on the market, and the fact that the Gigabyte board has support for many different FSB's, to keep the memory in check you need to have a set of dividers. Depending on what your FSB is to what ratio's are available, however, the ratios available are 400, 533, 600, 667, 800MHz or if you use a 1066FSB CPU you get an extra option of 888MHz. You can set the memory to whatever speed you wish independent of the CPU FSB however the best performance comes from when the memory and FSB are running at 1:1.
While having a wide range of frequencies is important, if you cannot boost the voltage to stabilise the main components, you are just spinning your wheels in the mud. Gigabyte only has four voltage controls, but all are important.
First is the CPU voltage, the all important one to keep the CPU running when the temperature starts to rise too much for the default voltage to work. You can adjust the voltage range from 1.3v up to 1.750v in 0.025v increments. This allows for a good range of selections no matter what core you are using. Though 1.75v on a Prescott or the Presler are not recommended, it's still nice they are there.
DIMM voltages keep the memory stable when pushing them to extreme speeds. Selections are from default voltage to a max of +0.7v in 0.1v increments. To this end you get from 1.8v up to 2.5v, which is the same voltage that DDR runs on - an extremely generous range here.
PCI-E voltage is actually a sort of misconception, not only does it give the PCI-E bus extra voltage, but also the Northbridge chipset itself. This range if from default to a max of +0.7v in 0.1v increments. Essentially from 1.5v to 2.2v. We wouldn't recommend going past 2v for this section.
Lastly is the FSB Overvolt option. This one provides a power boost to the CPU to Northbridge link to keep it as stable as possible at high clock speeds. Settings rage from default to +0.35v in 0.1v increments. So this gives 1.2v to 1.55v.
With all these options we managed a very healthy 351MHz FSB (351 x 12 = 4.2GHz) with memory running at 1:1, DDR-2 voltage at 2v, FSB voltage at +0.35v, CPU voltage at 1.45v and PCI-E voltage running at 1.3v. In all an extremely impressive overclock for an Extreme Edition CPU that tend to run warm even at default.