I'm going to get a top end 27" iMac. Initially I was going to upgrade the processor and video card and get a Fusion drive...however now I'm pretty sure I need the 768Gb flash option so I'm now desperately trying to cut back the other things so I don't blow too much dollar. I think the processor upgrade is worthwhile because of hyperthreading, for £120 I can basically double the number of cores I have (albeit in a virtual sense). So I'm thinking: how great is the advantage of upgrading the graphics card from the 675MX with 1GB to the 680MX with 2GB? I don't actually understand what having a better graphics card actually means. I mostly game on consoles, though I may fancy getting a new game every now and then but not really looking for big MMORPG or the latest ultra graphics games. Is it worth upgrading if nothing else than to future proof? Is the 675MX with 1gb a good enough card for the occasional gamer or is it really worth putting a bit more cash to get the 680 with 2GB?