I am using an Opteron 180 (dual core 2.4 GHz CPU). I would like to clock it a bit higher - to 2.6 GHz+.

If I set the CPU clock to 217 MHz, I get 2.6 GHz to the Opteron. If I run the PCIe bus synchronously, it will run at 108 MHz. If I run it asynchronously, I can set it to 100 MHz. What is the drawback of running the PCIe bus asynchronously? I've read on tomshardware that the PCIe bus should be able to handle 100-110 MHz.

Also, what CPU voltage should I be running at 2.6, 2.8, and 3.0 GHz? It nominally runs at 1.3 or 1.35 V. I'm using a 4-pipe cooler, which doesn't seem to ever get hot. The CPU is running at 47 C at 2.6 GHz and 1.4 V.