Is a single 500w enough??? (8800GTX)

Would an 8800GTX work safely with a 500W main PSU? or would i need an extra VGA PSU iv been looking at this VGA psu

ps.
1 I know there have been lodes of 8800 psu questions but non have given any indication of if a extra VGA psu is needed or in fact works (or at least of what I understood of them)

2 I don’t know any more info of my main 500w psu as it was in the case when I got it

3 any other power recommendations would be appreciated

yes thats wat im worried about, if i risk it i risk it i could do some damege to the card but as the vga psu is only like £25 i think ill just buy that as well and then i could have 2 8800GTX's in sli in the future

are you talking something like this?

http://www.thermaltake.com/product [...] /w0130.asp

that should work fine.

it wouldnt run the 88gtx in sli though.

i dont think you will need 88gtx,s in sli for a while.

OK iv done some more research and found that if the GTX draws 100% power through the pci-e bus an the its 2 extra connecters (75+75+75) 225Max which should be 18.75 Amp Max draw. And the GTS can only draw a measly 150w max which should be 12.5 amps MAX Either way this kind of draw is within the Operating ranges of this vga psu (i hope )

Also in my search i found some guidelins for psu's in (W)

Electric consumption
total of the system
GeForce 7900 GTX 256 Watts
GeForce 7950 GX2 277 Watts
GeForce 8800 GTS 273 Watts
GeForce 8800 GTX 308 Watts
Radeon X1950 XTX 280 Watts

These seem low figers to me :?

http://www.thermaltake.com/product [...] /w0130.asp
is certified for crossfire (e.g dual x1950) as add on PSU, and it has two pci express connectors which give : Max. Load 21A (Peak Load: 25A).
For x1950 pro ATI recomends 450W and 30A on 12v with a single PSU.
If you use only the one PCI express connector of Purepower w0130 PSU, for a x1950 pro AGP, you will get the same amperage ~25A, or only 25A / 2 ???
I have PSU tagan 480W with 28A on 12v, and with the second X1950 card I got (after I returned the first to the shop For the same boot problems) I have problems like the catalyst control center crashes when it tries to render the moving car on 3d settings and sometimes I cant boot to windows because the card stops sending signal to the monitor (when it tries to show the mouse pointer) and the monitor get on stand by mode so I have to reboot manualy.
Maybe the boot time is critical because all the hardware is testing so the demand for Wattage is very big and my PSU cant give the power needed.
But when I manage to boot I can play 3d games with out any problem for hours.
I'm thinking of buying a dedicated graphic card PSU, but I dont know If this is the problem with my rig.
EP-8K9A2+
Athlon XP 2800+
2 HD drives
2 dvd recorders
Antec 480w PSU 28A on 12v

P.s This model is recomended for SLI.