BIOS and Overclocking

BIOS Interface

For the P5E3 Deluxe ASUS uses their familiar AMI BIOS interface they’ve used for the past several years. The layout is a little unusual if this is your first ASUS motherboard, but over time we have grown used to it.

For overclockers the main settings you’ll want are found under the “Ai Tweaker” menu. Here you’ll find settings for adjusting all your speeds and voltages, as well as memory timings. The myriad of settings can be a little intimidating if you’re new to overclocking, which is why ASUS provides their overclock tuner setting which can be used to automatically overclock the system. Enthusiasts will want to get their hands on the speeds and feeds and here ASUS doesn’t disappoint, delivering FSB speeds up to 800MHz in 1MHz increments. You can also adjust the memory multiplier depending on your FSB speed. At 1333MHz FSB, DDR3 memory speeds of 667MHz, 800MHz, 835MHz, 887MHz, 1002MHz, 1066MHz, 1111MHz, and 1333MHz are available. You can also adjust PCIe speeds between 100-150MHz in 1MHz increments.


Voltage options are equally robust, with adjustable voltage settings for the CPU, FSB, DRAM, and North and South Bridges of the chipset. CPU voltages range from 1.10-1.70V with increments as fine as 0.00625V at most voltage settings. This allows you plenty of room to tweak the CPU voltage until you get it just right when overclocking. If for whatever reason you need more than 1.7V of juice to overclock your Core 2 CPU, ASUS also provides the CPU PLL Voltage setting, which can go up to 2.78V of additional juice for the processor. Unless you’ve got an ultra exotic cooler mounted on your CPU (read: liquid nitrogen) don’t ever touch this setting. In our testing we never go over 1.5V when OC’ing 65-nm Core 2 CPUs.

Besides the CPU voltage, FSB voltages of ranging from 1.20-1.50V are provided, while DRAM voltages range from 1.50-2.78V. Finally, for the North Bridge and South Bridge voltages range from 1.25-1.91V and 1.05V-1.20V respectively.


For newbies who may not know what voltages to select for these settings, ASUS color codes these last four voltage settings. So blue means the voltage you’ve selected is okay, yellow is warning, purple is strong warning, and red means danger. As an additional warning, if you really crank up the voltages for the North Bridge and South Bridge into the red zone, the BIOS will remind you to add additional cooling with the following message “**North Bridge needs a better cooling system! **”.


Another cool feature the BIOS provides is the ability to manually type in the voltage you want. If your voltage setting isn’t supported by the motherboard, it will automatically select the closest alternative setting.

Like previous ASUS motherboards if your OC is unsuccessful and the system isn’t able to complete POST, the BIOS will load up in safe mode with conservative BIOS settings the next time you reboot the system. Note that the motherboard won’t automatically reboot itself in safe mode however.

Overclocking

While the X38 chipset is officially limited to supporting FSB speeds up to 1333MHz, in our hands the chipset is capable of hitting speeds well beyond this frequency. Last week we pushed our Core 2 Extreme QX6850 to 472MHz FSB with Gigabyte’s X38-DQ6, and with our ASUS P5E3 Deluxe motherboard we were able to go even further, topping out at 490MHz FSB!

We were actually able to boot to even higher speeds but couldn’t get 100% stability within Windows. We think with more voltage we could have gone further, but we honestly were pleased with our results and didn’t want to push the issue. After all, that’s what our Core 2 Duo E6750 is for…

Armed with this CPU, we were easily able to break past the 500MHz FSB mark. We managed to hit an FSB speed of 518MHz on the ASUS P5E3 Deluxe motherboard.