Intel Core i5 655K @ 4.4GHz
8GB DDR3 1600MHz Dual Channel RAM
Gigabyte P55-US3L Motherboard
Zotac GTX275 896MB
Intel SSD 180GB 330 Series MLC 25nm SATA 6GB/s 9.5mm SSD
Western Digital 1TB SATA2
Corsair CX650 PSU

Thinking about getting a used component on Facebook as a band-for-buck upgrade. Any suggestions? If I spend £150 on a graphics card for instance, will I see a difference in games?

Wait, is this a proposed game system or the one you have right now and would like to improve on?

If the latter, everything is ok and I think you only really get an advantage out of expanding your RAM. RAM is dirt cheap now and I would just get 16 instead of 8. It won't be a massive difference in performance, but it won't be a massive difference in price either.

I know the games you like to play and there's no need to do a GPU upgrade for those. If this is a new system, I'd aim for anything within the 100-150 euro (quid) range. Anything beyond that is probably overkill. How much did/does this one set you back?

Actually both the GPU and CPU are outdated. The gtx released in 2009 and i5 released in 2010 and its only a 2 core cpu. You wont be upgrading the cpu without changing out the motherboard. So if you want a boost in frames-per-second or better gaming experience at fullhd the gpu upgrade is the way to go. A used 1060 6gb should be fairly cheap now. Or if you find a 1070, even better.

As always the visual quality comes from the game engine. So i'm not sure how much a difference you will be seeing. For instance Borderlands with its cell-shaded engine is always going to look sub-par compared to say Crysis no matter how much AA and filtering you throw at it. You will however get an increase in FPS which in turn means less stuttering and faster texture loads etc.

Took you up on your advice Peltz and got a use GTX 1050ti.

An excellent decision.

Everything runs silky smooth now. I'm surprised it was that simple after all.

I guess I should have considered you also play The Long Dark. That one chugs on my PC even and that's a very decent machines with a recent 250 euro GPU. Seems like the engine is pretty badly optimized (great looking game tho the art style I mean).