Concerns about power draw

Hardware Hub GPU
1

I bought a GTX 580 on clearance for £99, more of an impulse buy than anything, and I'm not sure whether my power supply can actually support it. I'm running a Corsair CX500, along with a Phenom II 965 BE CPU, one memory module and two hard drives. The card is reference, and none of my parts would be overclocked. What do you reckon?

EDIT: Reporting back, for anyone who cares or who is in a similar position, this setup seems to be working absolutely fine. I ran an OCCT PSU test for 3 hours with no crashes, and no crashes in games either. I'll be putting the PSU test on for a full 24 hours some time, but I'm fairly sure it's not going to pop my PSU.

2

test it and report back.

3

Ah, I should've mentioned, the card isn't actually here yet, I ordered it on Saturday.

4

but still. it might work, it might not. I'd say 80% it'll be fine. your powersupply might be underpowered but it's not very likely. also - add another ram module.

5

I'll just plop it in and run some synthetics when it arrives I guess, seeing as this power supply has overload protection.

6

500W is enough, easily

7

you got about 400W max in cpu+gpu, so your psu will have a hard time, but nothing impossible, if it is well-built 

just pop a 24h power supply test on occt, and see if it crashes, if not you're good to go.