The cpu themselves are locked from higher multipliers above its default, they are unlocked for the lower ones. But to take advantage of the lower multis your mobo must also support manual multiplier adjustment. From a PCStats review the Abit KV8 series does not allow manual multiplier adjustment. The CG stepping cpus have been having the best results for overclocking. And this part of a review from here at Anandtech tells about the AGP/PCI and the supposed effect at 233 fsb :
Finally, at a 233FSB setting, the multiplier kicks in and we are back to 66/33 spec on the bus. The problem, of course, is that you have to reach 233 on overclock for the lower multiplier to kick in. We could not reach 233 with our Athlon64.
While we have seen it reported elsewhere on the web that VIA does fix PCI at 33 and allows AGP to float, we can find no evidence supporting that in the Abit BIOS. Frankly, we place more confidence in Abit's Engineers than we do on what is reported at other sites with no evidence. Based on what Abit tells us, we still have every reason to believe there is no AGP/PCI lock on the K8T800 chipset. This is also supported by the fact that we have never been able to overclock as far on a VIA board as we have achieved on an nForce3 chipset motherboard, which does implement AGP/PCI lock.
Edit: Just a personal note most of the cpus used in these reviews are 3200+ and are more than likely the less overclockable stepping C0, the 2800+ may have a little more overclock room especially if you get a CG stepping. Regardless for overclocking the nforce 3 250 or k8t800 pro would be better choices since they do have the AGP/PCI lock ability. This board is still good for minor overclocking, usually around 218~223 fsb stable.
Facebook
Twitter