Windows 7: 650w PSU, how much power should be left to things other than graphics?

My current graphics card uses 450w, but my question is - I'm hopefully getting a new one soon - would I be able to upgrade to a card using up 500 or 550w of power? I just don't know how much power should be left to the rest of the system. Thanks!

You need to check the specs of each card as to what minimum wattage that's need and how many and what types of power connections. This will tell you what the minimum PSU you will need. Keep in mind for any future upgrades that will require more power consumption. There are wattage calculators you can use to give you an idea of what you might need. Just do simple google search for "PSU calculator".

Thanks! I'll try that out. I feel like an idiot, but can I find out my motherboard/CPU etc. without having to open up my computer? I've upgraded some parts, (mainly graphics card and PSU three years ago) but the rest came with the computer. I customized it at HP's website, but mostly went with what was recommended when I ordered it.

And I'm looking at two cards: one requiring 500w minimum, the other 550w.

I would not cut it too tight. The price difference between 550W and 750W is small. Why take risks.

I'm looking more at the 500w one anyway. That's not cutting it too close, is it? My current is 450 and has no problems. I could go with the card 2 generations after my current, if I have to - which requires the same amount of watts. I'd like the 500w one more though.

This may be a nitpick, but there ain't no such thing as a 500W graphics card. The numbers recommended by manufacturers are for the total system power.

75W is available through the PCI-E slot. A six pin PCI-E power connection is rated at 75W. Eight pin, 150W. That means that the most power-hungry cards on the market are limited to 300W, if they follow the nominal ratings.

I vaguely recall reading of some special cards that used two 8 pins, allowing up to 375W. That may violate some standard for PCI-E cards, though.

I like eVGA's recommendations for their graphics card. They list not only the power required but also a current rating at +12V. Meeting both would assure that you're not using one of the cheapo PSUs, which tend to have inflated power ratings relative to their 12V outputs.

This thread is very confusing to me, so I'll just ask if my 650W PSU can handle Nvidia GeForce GTX 670, which has a minimum system power requirement of 500w. If not, I'll just go with the GTX 660, which has the same power requirement as my current card - the GTX 460 SE.

Example on price difference between a 500w Corsair CMPSU-500CXV2UK Builder Series CX500V2 - 80 Plus Certified Power Supply: Amazon.co.uk: Computers & Accessories

and 750w Corsair CX750 Builder Series CX 750W ATX/EPS 80 PLUS Bronze PSU: Amazon.co.uk: Computers & Accessories

For the sake of £20 ish the 750w is the better option as it will cover your needs now aswell as some future upgrades. So you won't need to buy another next year. The Psu is the most important component and should never be skripmed on. Always buy a well known and reliable brand..

I currently have a 650W Corsair PSU. I just want to know if it will cover a graphics card which requires a minimum of 500W of system power. (I assume it should, but I never hurts to make sure.)

sorry shadedgrey i miss understood you. It was a bit early for me,
Your current pus is plenty enough for a Gpu that has a recomended psu of 500w
I'm currently running 2 x Gtx 670's with a 750w psu. The recomended is 700w for 2 way sli or 500w for a single one.
Hope that clears it up for you