In general I believe on any PC game I hit one of 3 limits. Either I have vsnch on and my FPS stays at 60, I don't have it enabled and either my GPU is pegged at close to 100% or I have some combination of CPU usage that is showing me I am pegged on a single core / 2 cores / all my cores.
However, on BF3 I don't seem to be hitting either of these. My FPS is in the upper 30s to mid 40s range (if it is available VSnynch is not enabled). My GPU is running at around 60% to 80% and my 3 cores are all running at 70% to 90% (which puts a total of over 2 cores but under 3 fully utilized and no single core ever seems to get to 100).
I am running BF3 at 1920 by 1080 with most settings at high except I think shadows at medium and I am not using the AA that is hard on the system (based on Tom's review).
So the challenge I have is it seems the neither my GPU or CPU are being fully utilized so I imagine I have some other bottleneck.
Is this due to a memory GPU limit (maybe the 1GB I have is not enough), speed of my main memory (I have plenty of available RAM when playing), some other bandwidth challenge with my old board, the game having special code to screw with tri core CPUs, or some other thing I am not thinking of.