Hi, I've been a PC user from the start and want to get completely converted to apple. I'm currently running i7 920 @ 2.67Ghz with 6 gigs of ram on a 64 bit os along with ATI Radion 5450. Mainly use it for photoshop and web development. Wanting to know if I would get at least the same performance, or better out of a base 27" iMac? Thanks in advance.