Overclocking

All the KT266A motherboards reviewed at PC Hardware in the past could be overclocked, the differences between these were the overclocking degree offered and the amount of BIOS features. Personally I think that the best overclocker is the motherboard which can do the job better, no matter how easy is the setup process. From the easiness point of view Abit is really an innovator, their SoftMenu III features were the first to deliver a lot of options without sacrificing stability.

The FSB can be freely adjustable between 100 and 200Mhz in 1Mhz increments. The multiplier is also adjustable, between 5x and 13x. The highest 13x setting allows you to overclock the CPU up to 1733Mhz with a 133Mhz bus.

Of course that you can go even higher, but you have only one choice: increasing the FSB. The CPU voltage options are satisfactory: KR7A lets you select the CPU voltage, the I/O voltage and the DDR voltage. The most important voltage which has to be increased in an overclocking session is the CPU voltage which can be adjusted up to 1.85V in 0.05V increments. For the I/O Voltage you have two options: 3.50V or 3.65V and the DDR voltage allows 2.55, 2.65, 2.75 and 2.85V settings. As you can see in the left picture the Ratio can also be modified between 4:2:1 and 3:2:1. The fast Command Decode is an option which can be found in other BIOS and I have already explained in previous reviews what does it mean. SoftMenu III also allows the selection of DQ Control. That's quite a less common feature which permits the selection of the host bus clock delay source, but I don't see why and how it can increase performance or stability.

I really liked the DRAM Clock/Drive Control BIOS section. The memory setting section allows the user to adjust most memory timing aspects: the ones which increase stability and the ones which increase performance. Abit didn't provide memory timing templates, but almost any user can adjust settings to achieve maximum performance with the help of the board's manual. Don't expect detailed explanation, but you can find out there a point to start. We played a little with an 1.4Ghz Athlon 1600+ CPU. I tried to increase the FSB as much as possible, that's why I have chosen a 9x multiplier which should allow me to increase the FSB to the maximum. I got very pleasant overclocking results with other motherboards based on KT266A, that's why I expected a lot from KR7A. I increased the CPU Voltage to 1.85V and the DDR Voltage to 2.6V. No modification was made on I/O Voltage. The maximum FSB we were able to get was 164Mhz, the motherboard being perfectly stable at 1478Mhz. For performance comparison purposes I set the CPU to run at 12 x 133Mhz.