Is it worth me upgrading from a 955 to i5 2500k mainly gaming at the moment . I purchased the 955 middle of last year or should I keep it and upgrade to a 6 core later on. I have an ATI 6870, also i have 4GB DDR3 1333 cl7 which i paid over £60 last year and it is not compattible with my AM3 board but i hear it is designed more for the i3,i5,i7.
If i do upgrade I was going to sell the 955,asus m4A785td-v-evo, 4GB zeppelin DDR3 1333 and vista home premium(OEM) for £199 is that too steep.
No. You need at least a new mobo + CPU which will run you around $270-300. Games do not utilize 4 cores and most games are bottlenecked at the GPU. Upgrading your GPU or monitor is more noticeable depending on what resolution you play at.
Yes a 2500k would be a pretty big boost from a 955, but is the 955 too slow for you now? Realistically if you overclock a 955BE it shouldn't hold back a single 6870 or even dual 6870s IF your using eyefinity. As for upgrading to a 6core CPU it really isn't worth it for gaming, most modern games like more than two cores but don't benefit much beyond three, but if you spend a lot of time encoding videos or something then it's something to think about.
Anyway, it depends on you and what games you play. If your setup is enough for you right now, then I say wait till the fall at least. Bulldozer will be out soon and even if you go with Intel they will probably drop their prices a little to put pressure on AMD. Their high end LGA 1366 replacement is also around the corner