ASUS A7V133 Socket-A KT133A ATX

What's the redline?

When we were reviewing KT133 motherboards, we found out that 115MHz was the maximum a KT133 motherboard could sustain, with 110 MHz a much more reasonable limit.  Since FSB overclocking was not that useful, we figured that it would be interesting to see how much we could overclock a CPU by changing the multiplier and then the FSB, since multiplier overclocking proved to be more effective.

However, with the KT133A chipset, FSB overclocking is worth a closer look with the new official support for 133MHz FSB operation.  With the KT133A chipset, we are sure that FSB speeds of up to 133MHz are no longer a problem, but we decided to find out how high above 133MHz can we push the FSB speed.

To do this, we took a 1GHz Athlon processor, a Mushkin PC133 CAS2 PC133 SDRAM, and a NVIDIA GeForce2 GTS as our test bed.  We started the testing by setting the 1GHz CPU to run at 133MHz FSB, thus a multiplier ratio of 7.5.  Then we gradually increased the FSB speed and ran tests to make sure the system was stable at that speed.  If needed, we also tried to set the CAS latency to 3 and all other memory timings to as slow as possible, so that the PC133 SDRAM would not be the limiting factor.  Moreover, when the CPU speed got to high, we lowered the multiplier ratio setting so that the clock speed of the CPU remained close to 1GHz.

For our testing, initially with CAS2 and normal memory settings, the highest FSB speed we achieved was 145MHz.  At that speed we could still run SYSMark 2000, Quake III Arena, and Content Creation Winstone 2000 with no problem.  However, setting the FSB speed to 146MHz the system couldn’t boot at all.  This value is slightly higher than the one achieved by the ABIT KT7A-RAID and the MSI K7T Turbo.

We then lowered the CAS setting to 3 and reduced any other memory related settings in the BIOS, allowing us to get the FSB up to 148MHz and ran all the tests with no problem.  At 149MHz, the system could not boot again.  This result is also slightly higher than the one achieved by ABIT and MSI

Like what we have mentioned in the previous reviews, 148MHz is around a 10% overclock from 133MHz - the same percentage increase we had with the KT133, so this is no major surprise.