Somes games can run FASTER with a better CPU even if the graphics card is the bottleneck. (the explanation is kind of confusing.)
As for upgrading:
1. Open the Task Manager (CTRL-ALT-DEL)
2. Run a GAME for five minutes
3. Close the game.
4. Look at the Task Manager and analyze the results.
You need to see ALL the cores. Hyperthreading also needs to be OFF in the BIOS to avoid confusion. Now, let's assume we're looking at FOUR PHYSICAL CORES and no hyperthreads:
At least one core hits 100%.
The CPU is the bottleneck (or close to it). Don't bother getting a better graphics card.
One or two of the cores hit about 50%.
You can get a card that scores roughly DOUBLE the framerates as your current graphics card before bottlenecking the CPU becomes an issue.
*This is pretty simplified, and of course not all games can use all threads but if you look at the two MOST used CPU CORES you can estimate how much BETTER of a card you can get then look at benchmarks to see what the card would be.
- test with hyperthreading disabled
- observe ALL cores (view-CPU history- one graph per CPU)
- future games will use all four cores better (meaning a better card can be used for those games)
- GAMES vary their CPU usage. AVERAGE at least four games (two shooters and two Starcraft 2 style games)