BIOS options
A good BIOS is essential to squeezing the best possible performance from a system, and all these boards come well equipped. However, there are some important differences between their tweaking capabilities, which we've highlighted in a handy chart below.

Abit IP35 Pro Asus P5K Deluxe Asus P5K3 Deluxe Gigabyte GA-P35-DQ6 MSI P35 Platinum
Bus speeds FSB: 133-600MHz in 1MHz increments
PCIe: 100-200MHz in 1MHz increments 		FSB: 200-800MHz in 1MHz increments
DRAM (1066 FSB): 667, 800, 889, 1067MHz
PCIe: 100-150MHz in 1MHz increments 		FSB: 200-800MHz in 1MHz increments
DRAM (1066 FSB): 800, 889, 1067MHz
PCIe: 100-150MHz in 1MHz increments 		FSB: 100-700MHz in 1MHz increments
PCIe: 90-150MHz in 1MHz increments 		FSB: 1-1000MHz in 1MHz increments
PCIe: 100-200MHz in 1MHz increments
Bus dividers CPU:DRAM: 1:1, 1:1.2, 1:1.25, 1:1.5, 1:1, 1:1.66, 1:2 NA NA NA CPU:DRAM: 1:1, 1:1.2, 1:1.25, 1:1.5, 1:1, 1:1.66, 1:2
Bus multipliers NA NA NA DRAM: 2.5, 3, 2, 2.4, 3.33, 4 NA
Voltages Vcore: 1.325-1.895V in 0.01V increments
Vdram: 1.8-3.0V in 0.025V increments
Vcpu vtt: 1.2, 1.23V
Vmch: 1.25-1.72V in 0.04-0.08V increments
Vich: 1.05-1.38V in 0.03-0.07V increments
Vich io: 1.5-2.0V in 0.05-0.1V increments
Vddr2 ref: -4-2% in 2% increments
CPU gtlref 0&2: 45-80% in 1% increments
CPU gtlref 1&3: 45-80% in 1% increments		 Vcore: 1.1-1.7V in 0.0125V increments
Vcpu reference: 0.57x-0.63x in 0.02x increments
Vcpu pll: 1.5-1.8V in 0.1V increments
Vdram: 1.8-2.15V in 0.05V increments
Vfsb termination: 1.2-1.5V in 0.1V increments
Vnb: 1.25-1.7V in 0.15V increments
Vnb ref: 0.61x, 0.67x
Vsb: 1.05, 1.2V		 Vcore: 1.1-1.7V in 0.0125V increments
Vcpu reference: 0.57x-0.63x in 0.02x increments
Vcpu pll: 1.5-1.8V in 0.1V increments
Vdram: 1.5-1.85V in 0.05V increments
Vfsb termination: 1.2-1.5V in 0.1V increments
Vnb: 1.25-1.7V in 0.15V increments
Vnb ref: 0.61x, 0.67x
Vsb: 1.05, 1.2V		 Vcore: 0.5-2.35V in 0.00625V increments
Vdram: +0.05-1.55V in 0.05V increments
Vpcie: +0.05-0.35 in 0.05V increments
Vfsb: +0.05-0.35V in 0.05V increments
Vmch: +0.025-0.375V in 0.025V increments		 Vcore: 1.275-2.0625V in 0.0125V increments
Vdram: 1.8-2.6V in 0.05V increments
Vcpu vtt: 1.175-1.55V in 0.025V increments
Vnb: 1.25-1.625V in 0.025V increments
Vsb io: 1.5-1.8V in 0.1V increments
Vsb: 1.05-1.15 in 0.1V increments
Fan speed control CPU, SYS, AUX1, AUX2, AUX3, AUX4 CPU, SYS CPU, SYS CPU CPU, SYS

Although the boards differ in terms of the maximum front-side bus speeds they support, each offers enough headroom for serious overclocking. They all serve up CPU multiplier control with run-of-the-mill Core 2 processors, as well.

The BIOSes start to diverge on the memory front. You get a standard array of timing options with each board, but how the memory speed is set varies from manufacturer to manufacturer. Abit and MSI favor a simple CPU:DRAM divider, and there are plenty of options to choose from. These manual settings are particularly important for the P35 Platinum, since our board's BIOS never seemed to get the hang of the "Auto" setting. We also had to pump additional voltage into our Corsair DIMMs just to get that board to boot.

Coming at memory clocks from a different direction, the GA-P35-DQ6 makes six memory multipliers available. That's one less option than you get with the Abit and MSI boards, but at least two more than with the Asus P5Ks. Those boards only offer a handful of memory speed options.


Gigabyte consolidates much of its BIOS functionality on one screen

Moving to voltages, we have a myriad of options available on each board. The DQ6 provides the highest voltage ranges for both the CPU core and system memory, making it the most likely candidate for extreme overclocking. All five boards offer enough voltage tweaking functionality for the liquid-nitrogen-free end of the overclocking spectrum, though. The IP35 Pro and P5Ks have the distinction of offering more voltages up for manipulation, although most folks will only need access to the basics.


Abit's excellent FanEQ fan speed control


Plenty of hardware monitoring, too

We see more divergence when moving to fan speed control and hardware monitoring, where Abit's phenomenal µguru takes the cake. The IP5 Pro's BIOS offers temperature-based fan speed control for all six of the board's fan headers, and you can dictate not only temperature thresholds, but actual fan speeds and reference temperatures for each. Combine that with extensive hardware monitoring capabilities that allow users to set alarm and shutdown conditions for system temperatures, fan speeds, and a wide range of voltages, and the IP35 Pro looks much better equipped than its competition.

Abit hasn't upgraded µguru's capabilities in years, likely because the rest of the industry still lags far behind. You do get automatic fan speed control with the other boards, but such control is limited to one or two fan headers and lacks the fine-tuning options that µguru provides. None of the other boards offer anything close to µguru's BIOS-level hardware monitoring, either.


Abit's µguru Windows software

µguru's functionality extends to Windows, where you can manipulate just about every bus speed, voltage, fan setting, and alarm or shutdown condition with software that Abit provides. System setting profiles can also be saved and invoked automatically when certain applications are launched, allowing the board to ramp performance for games and lower noise levels for media playback.


Asus gives you AI Suite...


And PC Probe

The others have Windows tweaking and hardware monitoring software, too. Asus offers an app for each, with PC Probe covering hardware monitoring and AI Suite handling overclocking and fan speed control. PC Probe is particularly flexible, especially when it comes to interface customization, but the AI Suite feels a little basic next to µguru's wealth of tweaking options and profile support.


Gigabyte's Easy Tune

At least the Asus software offers a better interface than Gigabyte's Easy Tune 5. This app gives you basic overclocking and fan speed control, but it looks awful and isn't particularly easy to use. You're better off poking around in the BIOS.


Dual CoreCenter from MSI

MSI's Dual CoreCenter isn't much prettier than Easy Tune, but it offers more tweaking options and an easier-to-use interface. The app also monopolizes entirely too much desktop space. Why can't mobo makers build tweaking applications that actually look like Windows apps?