Lower your Hypertransport to 3X. Lower your Ram speed, like say if your running DDR 400 drop it to 333. Then start raising your FSB up by a few MHZ at a time. When it starts locking up back off on the FSB till it runs stable. You can raise the voltage on your CPU to get higher but you need to keep a eye on your temps if you raise the voltage
ok here are my settings.
DDR voltage adjust: 2.60 V
CPU Clock: 200 mhz
dram clock: auto
dram command rate: auto
dram cas# latency time: auto
LDT Bus Frequency:800 mhz
pci delay transection: enabled
Start changing the CPU clock one at a time. Do a small 5-25MHz jump not 100MHZ or so. Keep the voltage at stock unless you are overclocking alot and need to keep the system stable