The Phenom II 810's default clock is 2.60GHz, but with a fairly high 1.300V VCore. As we have already stated in our Phenom II 940 Review
, this is quite high for a 45nm CPU, but less cache should help to keep the energy consumption lower.
Overclocking in BIOS is not that easy. First you have to increase the virtual FSB, then you have to calculate the HT speed, so you should make sure not to exceed it by too much, as that would make your system unstable. Besides that, your memory speed will also increase, so either lower it or buy modules which support speeds of 1000MHz and more. The new BIOS 1.60 for the MSI DKA790GX features new overclocking options. You can set the voltages not only for the core, but for all the parts of the CPU, including the integrated northbridge. This helps in lowering the VCore, but due to other higher voltages, the power consumption will suffer greatly. After some testing, 100% stable results were achieved at 3.406GHz, which is nice, since it's a hefty 800MHz overclock.
While idling the CPU downclocks to 800MHz and the VCore drops to 1.0000V, regardless of the VCore setting in the BIOS. This may cause trouble with overclocking, but our CPU ran fine with Cool'n'Quiet enabled, because the other voltages were high enough. Disabling Cool'n'Quiet will cause a 20W to 30W increase in power consumption while idling.