I set everything to ultra and my Frame rate becomes 15. Playable but kind of slow. Is it because I only have 4Gb of RAM?
Mostly it's video settings.
But the answer also partially depends on what else you have running on your iMac when you are playing WoW. In general 4GBs is enough if you don't have much other stuff going on.
You don't need more than 4gb of ram for WoW. The game doesn't even use 2gb of ram.
While the game itself doesn't use more than 2GB, there are files that WoW uses that are cached in memory. The more memory you have, the more of this data that can be cached in memory. However, that still doesn't necessarily mean you need more than 4GBs.
However, lets look on my system for a moment for real memory usage:
- Firefox 600 Megs
- Safari 250 Megs
- iTunes 300 Megs
- Mail 100 Megs
- Adium 100 megs
- Kernel 400 Megs
- WindowServer process 100 megs
- etc
Note that these numbers are rounded up at most by 10 megs and I didn't include all the various processes taking up memory.
Anyway, that's 1750 Megs of stuff I have running not counting what I'm currently working on or playing.
One way to find out if you're memory bound is in terminal run: du -ms /var/vm
On my system it's 256 - which is in megabytes. In general the best way to check this is a few time over a few of days normal usage after restarting the system.
On my system with only 4GB of ram, it frequently went to 2048 or more for swapfile usage. At 8GB ram, it stays at 256MB swapfile usage.
So in short 4GB is possibly enough, but it may not be and the best way to check is to see how much swapfile space is in use. In all probability if you do need more memory, you won't need to go to more than 8GB.