question about my sapphire 3850 pencil mod..

I was able to drop R1222 down far enough to allow 1.43vgpu...

But weird thing is, my core is just not stable past 837mhz even at that vgpu.
I have AC Accelero S1 on it with the fans....it stays cool...
I have the correct bios installed on it thats not locked @ 862mhz..

Is the core I got just a really weak one?

Only thing I can think is, I dont believe I have any heatsinks on the mosfet section of the board where that group of 4x4 mosfets...
Could those be overheating and causing the low clocks?
hrm....