I've got a Q9550 at 3.40 GHz up from the stock 2.83 GHz. I'm not in any hurry to upgrade due to a large backlog of older games I haven't gotten to. It maybe smart to look up benchmarks for games you actually play performed on a system with a similar graphics card to get a decent estimate of how big the difference could be. I've been surprised by how different specific games can perform in the past.
You are aware that you will need a new motherboard, and possibly RAM right?
Amen to this.
Thinking that you can upgrade just the CPU is not smart. Especially with DDR2 and an older generation CPU.
May want to save a little more and do a full overhaul. Not sure if you are near a Microcenter, but they are known for cheap CPU's and mobo's. I got my combo for about $220 and then all you would have to do is upgrade the ram, which is cheap nowadays. (4 gigs for 50$ maybe)
Intel i5-2500k @ 4.0 ghz | 8GB G.Skill DDR3 RAM | Sapphire Radeon 6970 | ASRock Z77 Pro | CM - Hyper 212 | OCZ 700W PSU | CM - Scout | 24'' LCD 1080p | 5.1 SS
i am in the same boat as Cobra. i am currently running BF3 at 55 fps esily, so i am finding no real reason to upgrade from this cpu yet. i personally feel any core2quad clocked 3.5-ish isnt worth the hundred of dollars upgrade to i-anything.
cpu wise, you really arent gaining much real world performance, or game performance. yes, there is a increase, just not enough to warrant the $350 for a core system. if you cant overclock, or dont want to, then the answer is clear tho.