I happened to win an ASUS EAH4890 1GB card and just popped it into my system today. I ran 3Dmark06 right away and was terribly dismayed by the result: a mere 10300. I ran one test at stock speeds and one with a 975/1010 OC.
The card that it replaced was an XFX 9800GT that was able to get a 11-12000.
My processor is a measly Athlon X2 5600 @2.6Ghz which no doubt is bottlenecking the card but why would it be lower than the 9800?
Its not being underpowered, since I'm on a 750W single rail.
I've got everything on a Gigabyte M57-SLI-S4 board with 4GB RAM running Windows Vista 64.
Is there a problem with the card or is it a simple bottleneck?
Did you do a full reformat before switching cards (or at least very carefully removing all the NVidia drivers with something like driver sweeper)? I always do a full reformat just to avoid weird conflicts. Also, try it in some games and see how it does there. I've often see poor 3D Mark results come up even when games run great.
Try running prime95 and memtest to make sure there is not some other instability in the system.
If the Vantage physics (CPU) is crashing, there may be some software glitches/corruptions in the system. If we can't find another culprit, you may have to do a complete reformat (which, like I said I always do just to avoid the headaches that come from mysterious issues that come up half the time when doing a simple swap).