graphics card

Hi everyone! I've been a member on SS.org a couple of months and I really like the forum :wub: I visit the music-related sections a lot, but now I feel the urge to explore the unknown territory of the forum :P And now I have a reason to do so too I own an iMac 21,5" from 2011, which soon will...

So I just ordered a new Radeon HD4650 for my computer last night and should get it tomorrow. The specs said the power supply needs a 450w power supply, which I doubt my computer has. At the moment I really don't want to spend $50 on a new power supply, as I am saving up for a new 7-string and...