Maximum PC

Hi everyone I am currently trying to get the most out of my CPU via overclocking.
I can get to a 12.5% overclock with only a minor CPU voltage increase but I have hit a brick wall at 15% (230 bus freq and 1.5V on the CPU for 3.22 Ghz).
At these setting Prime95 and OCCT stability tests fail. Note thou that the AMD Overdrive Stability Tests pass the default 1 hour test.
What should I do next to get past this brick wall?

Here is my current setup:

CPU: Athlon II X4 630 (stock 2.8 GHz 14x multiplier)
Motherboard: BIOSTAR TA-790GX A3+
Memory: 4 GB (2 GB x 2) of OCZ3G1600LV2G
CPU Cooler: Corsair Hydro H50
CPU Voltage: 1.5
NB Voltage according to BIOS: 1.2V (thou this reports around 1.17 in windows).
My memory is not overclocked per OCZs documented timing/frequency
I’ve also dropped the HT Link multiplier to try and eliminate this as an issue (currently at 8x).

I don’t think I should increase my CPU voltage any further as I’ve gotten nothing for my last .5 increase. Am I wrong?

Thoughts on what I should do next?

Thanks,
Paul

If that's a locked chip then bumping the bus speed is all you can do. However you can try to lower the multi and bump the bus speed more. But taking 2.8 to 3.2 is still a good overclock, I would just take it at that and be happy.