Will these components work?

Robomoo

Honorable
Jun 13, 2013
29
0
10,530
So I was planning on buying this graphics card (quite an upgrade from my current 6670) :https://www.aria.co.uk/Products/Components/Graphics+Cards/AMD+Radeon/Radeon+HD+7870+Tahiti+LE/PowerColor+PCS%2B+Myst.+Edition+Radeon+HD+7870+%28Tahiti+LE%29+OC+2GB+GDDR5+Graphics+Card+%5BAX7870+2GBD5-2DHPPV3E%5D+%2B+4+FREE+GAMES%21+?productId=54322

..when I realised my PSU wasn't good enough/ didn't have the right pins or whatever. I thought this wouldn't be a problem and that I could get a decent PSU to fit my system for £20-£40, but then everywhere on the internet recommends like £80-£120 PSUs for gaming systems, it seems. I found these which look like they would work, but really I have no idea:

http://www.scan.co.uk/products/500w-zalman-zm500-gs-uncertified-quiet-fan-atx-v23-psu
http://www.scan.co.uk/products/500w-cooler-master-b500-b-series-85-eff-psu-120mm-quiet-fan

Any advice? I'm completely lost and now unsure if the rest of my system will be compatible either... thanks for any help.