Graphics card.

[Whacker]

You'll get some additional performance, but your CPU/mobo/ram will be your choke point. Games these days are much more cpu limited than gpu. You can get an Intel 2500k, decent Asus mobo and 8gb of g.skill ddr3 for not a whole lot, and the 2500k will overclock like a beast even on stock cooling.

[Greyblades]

I honestly didn't expect that, I'd normally think my quad core and 8gigs of ram would be pretty good.

[Furunculus]

Games these days are much more cpu limited than gpu.

i'd say the opposite personally.

my mum has my old pc with a Q6700 (the one up from here) paired with a GTX460 (the one down from 560Ti) and she is going great-guns on skyrim with graphics maxed out and all that jazz.

if GB were going to spend £450 on a top of line AMD 7970 then i would agree that his Q6600 would be a bottleneck, but, a £150 560Ti should be more than worth his while.

[Greyblades]

So 560Ti is a good choice?

[Husar]

I'm with Furunculus.

Some games are somewhat CPU-limited because they don't use all four cores of a quad core.
Other than that a lot of my problems seem to stem from my GTX 460 having only 768MB RAM.
It still runs Skyrim with the official high res textures and almost maxed out otherwise really well. A few small hickups, but those only seem to come with the high-res textures and are probably VRAM related as I said.

And I have an AMD Phenom 2 x4 [high number, 965?] BE, which isn't far from your Intel IIRC.

[Greyblades]

Ok I've bought it and I've got it right now, now to find an online guide on how to install it safely without reducing it to a expensive paperweight.

[Furunculus]

these should do you:

https://www.youtube.com/watch?v=5ILrq7lMe-0
https://www.youtube.com/watch?v=O9x097QRXeA

[Greyblades]

Thanks, though I found my own yesterday.
I've got to say I've noticed an improvement since I installed the card, though not the 100Kps on Kingarthur 2 or shogun 2 at maximum graphics I was hoping, though I'm not exactly sure why I was expecting that from a £150 card.