While i still have this CPU i thought i would run a little experiment to try and answer the age old question of how many cores BF3, with its Frostbite 2 engine actually uses.
GPU used; 7870 @ 1185 Core / 1450 Memory.
CPU used; AMD Phenom II x6 1090T
Game settings; Ultra Preset @ 1920 x 1080P (Going Hunting)
I down clocked the CPU to 1.2Ghz to get a definite Bottleneck to the GPU and then turned off a number of cores in the BIOS.
First running 2 cores, then 4 and finally 6.
GPU and CPU usage is underlined in red, as is FPS.
Starting with 2 cores at 1.2Ghz.
GPU usage = 27% / CPU usage = 99.8% / FPS = 31.
As you can see the CPU is completely pegged and the GPU is only just working at a quarter, FPS are also very low.
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4 cores at 1.2Ghz
GPU usage = 76% / CPU usage = 91.1% / FPS = 47.
With the extra two cores at the same speed the GPU usage has increased dramatically, as have the FPS while the CPU has tailed off slightly. But the GPU is still bottle-necked.
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6 Cores at 1.2Ghz
Now with 6 cores, again at the same speed, the GPU usage is almost maxed, the FPS have also increased again; now at a nice 70 FPS, the CPU is now at a reasonably comfortable level.
GPU used; 7870 @ 1185 Core / 1450 Memory.
CPU used; AMD Phenom II x6 1090T
Game settings; Ultra Preset @ 1920 x 1080P (Going Hunting)
I down clocked the CPU to 1.2Ghz to get a definite Bottleneck to the GPU and then turned off a number of cores in the BIOS.
First running 2 cores, then 4 and finally 6.
GPU and CPU usage is underlined in red, as is FPS.
Starting with 2 cores at 1.2Ghz.

GPU usage = 27% / CPU usage = 99.8% / FPS = 31.
As you can see the CPU is completely pegged and the GPU is only just working at a quarter, FPS are also very low.
--------
4 cores at 1.2Ghz

GPU usage = 76% / CPU usage = 91.1% / FPS = 47.
With the extra two cores at the same speed the GPU usage has increased dramatically, as have the FPS while the CPU has tailed off slightly. But the GPU is still bottle-necked.
---------
6 Cores at 1.2Ghz

Now with 6 cores, again at the same speed, the GPU usage is almost maxed, the FPS have also increased again; now at a nice 70 FPS, the CPU is now at a reasonably comfortable level.
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