3dmark06's sm2.0 drops in half while o/c'ing the x2 3800+

[videopho]

Over-clocked @ 2.38ghz then ran and finished 3dmark06 (default) only to find out the 3dmark06 to drop to a high 4k instead of the 6k'ish. Further investigated, only to see the sm2.0 score drops in half. Otherwise all other scores look fine or in line, including the cpu one.
Drop back down to 2.36ghz from 2.38ghz, everything is fine, once again.
What makes the SM2.0 to drop in half?
See my rig in sig (AMD).
Video card is 7900GTO

 

[tersome]

What motherboard do you have? Is your pcie locked?

 

[videopho]

ECS-K1.
Yes PCI-E is locked.

 

[myocardia]

That's what happens when you aren't giving your processor enough vcore, it's performance goes down, instead of up. Although, with an A64, it can/will happen if you go too far above 1,000 HTT, but that shouldn't be the case with yours, unless you're running @ less than a 9.5x cpu multi.

 

[VirtualLarry]

Originally posted by: myocardia
hat's what happens when you aren't giving your processor enough vcore, it's performance goes down, instead of up.

That doesn't make any sense. Vcore does not affect performance. Either the CPU has enough Vcore to perform at a given frequency, or it does not. If it does not, it will error. Not perform slower at the same frequency.

Originally posted by: myocardia
Although, with an A64, it can/will happen if you go too far above 1,000 HTT, but that shouldn't be the case with yours, unless you're running @ less than a 9.5x cpu multi.

I thought that running faster than the chipset's HTT speed would cause system errors. Dunno about slowdowns from that.