Power issue?

[RossG]

Today I picked up an nvidia 9800gx2. I've gone to install it but when I power on my system, nothing happens. Now I know these cards eat power for breakfast then ask for seconds so I probably just havent got the power to run it, but id thought id ask just in case im missing something.. The PSU in question is a Corsair HX520W that has been faultless. Both 8 pin and 6 pin power cables are connected to the card. When I boot there is a millisecond red flash from an led in the graphics card, but no other sings of life from the machine. However if i take out the 8 pin connector to the card, the machine does boot, albeit with BIOS error bleeps, which is to be expected. With the 8 pin plugged in and the 6 pin out, it is the same as before, no life.
I am slightly surprised since I know theres others out there running this card on the same PSU. I am only running the core components of the computer and a hard drive. Its powering nothing else, not even a DVD drive.

So is it the obvious, I just lack the power, or could I be overlooking something else?

 

[Tealc]

Apparently the max power draw of the 9800gx2 is 'only' 197 watts so if this causing a power issue then your HX520W must be on the weaker side for a 520W unit. You should have around 200W spare unless you are running dual CPUs.

 

[RossG]

I'll give you the full spec:

Gigagyte GA-965P-DS3 rev1
E6300 (taken the clocks off atm so running at 1.8ghz, usually oc'd to 2.6)
AC Freezer 7 Pro
6GB ram over 4 sticks
Corsair HX520W
1x320GB Seagate HD
2 120mm case fans

And thats it. That stuff cant be drawing much power at all, yet it seems I still dont have the headroom for the extra grunt the 9800GX2 demands.
Is there any way to test how much my PSU can chuck out with a piece of software? Also the default speed on the PCI-X bus in the BIOS is set to 90. I usually put it up to 100 when oc'ing. Could this be a factor at all?