Athlon II X4 too low than average

[nemo14]

I tested an Athlon II X4 640 on motherboard with 880chipset getting as CPU Benchmarks 3050 (more or less) which is defintely lower than average result (3477).
I kept my PC on all night long and I have run the Performance again this morign getting 3410!
So I reboot my PC and re-run the Performance test still getting 3030/3050.
Checking the two baseline I noted a great difference on CPU Multimedia instruction and CPU Physics, but I change nothing!

Suggestion to reache a valuse as close as possible to average?

Thanks.

[David (PassMark)]

Maybe there was some random background activity on your PC. This can often happen just after a boot, but will decrease after the PC has been idle for a while.

See also this post.
Causes and Solutions for a slow PC