MSI K7T Turbo Socket-A KT133A ATX

We have seen this Peak before

When we were reviewing the KT133 motherboards, we found out that in general 115MHz was the maximum a KT133 motherboard could sustain. 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 144MHz.  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 145MHz the system couldn’t finish any tests successfully. This is also the peak FSB achieved by the ABIT KT7A-RAID at the same setting, and is 4MHz higher than the EPoX EP-8KTA3.

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 147MHz and ran all the tests with no problem.  At 148MHz, the system could not even boot. Coincidently, this peak FSB is also the peak achieved by the ABIT board at the same settings. The EPoX board could only achieved 145MHz because it doesn’t have 1MHz increments for FSB speeds.

Once again, 147MHz is only around 10% overclocking from 133MHz. Even from the old 10 – 15% FSB overclocking with the KT133 chipset, the KT133A should be able to achieve higher FSB speeds. So that means the memory has become the limiting factor.

Also, as we mentioned before, our sample of the K7T Turbo does not have a HSF unit on the 8363A North Bridge. Instead they just put a normal heat sink on the North Bridge. From our testing we have shown that at 147MHz, the heat sink is still capable of cooling the North Bridge to a suitable range. On the other hand, since the memory is the limiting factor now, the question still remains on whether the North Bridge can stand the heat at even higher FSB speeds without a fan.