Performance issue, very bad FPS and FPS drops

Hi,

I realize that there are 29 pages of this already but after wasting over a day of my life I thought I should share my findings.

I also was suffering slowdown issues with NFS Rivals when normally I have no trouble playing the latest games at high/ultra settings at the max resolution of my TV which is 1360x768. In short the CPU was my problem but read on if you want more info.

Specs are:

+ win 7 64-bit
+ H61 Motherboard
+ i3-3225 3.3GHz cpu
+ GTX 555 gpu - driver 331.82
+ 8GB RAM
+ Resolution: 1360x768
+ Game settings: All Ultra, Ambient Occlusion Off.

results during gameplay:

+ FPS between 26-30 (This is the problem!)
+ GPU Load up to 75%
+ CPU Load up to 60%
+ RAM up to 3.2GB

Low setting and lower resolution made no real difference, it only changed GPU load which dropped to 45%. Here's what else I tried:

1. Various Nvidia driver versions starting at 320.49 - No difference

2. Changed GPU to GTX 660 OEM (1.5GB) - No difference except GPU load dropped

3. Changed GPU to AMD HD7850 (2GB) with Catalyst drivers 13.12 to eliminate possible Nvidia driver issue - No difference except GPU load dropped

4. Fresh install of win 7 64-bit - no difference

5. NFS rivals with/without latest EA patch - no difference

6. New CPU, i5 2320 3GHz (approx 25% faster than the i3 3225 3.3GHz) - WORKED!!!

Specs after step 6:

+ win 7 64-bit
+ H61 Motherboard
+ i5-2320 3GHz cpu
+ GTX 555 gpu - driver 331.82
+ 8GB RAM
+ Resolution: 1360x768
+ Game settings: All Ultra, Ambient Occlusion Off.

results during gameplay:

+ FPS solid 30
+ GPU Load up to 75%
+ CPU Load up to 40%
+ RAM up to 3GB

So despite there not being any obvious bottle neck on the CPU it seems to have solved my problem, why I have no idea. One interesting observation is that the i3 is a dual core cpu (when you look at in task manager you see 4 threads (I assume this is something to do with hyperthreading?)),  where as the i5 is a quad core cpu. During game play task manager shows only 3 of the 4 threads in use on the i3,  but on the i5 it shows all 4 in use. Could the problem be related to poor coding around dual core cpus, all this is despite them not even reaching any where near 100% load on any core.

Hope this helps others, if not EA read and fix!