Is something wrong with my memory frequency?

[M20]

Bear with me here, I am not too savvy with these things..
I have corsair xms3 memory and it says 1600Mhz on the box..
but this is what I see in cpu-z.. I must admit out of curiosity I used the gigabyte easytune software once, I wasn't really sure what i was doing, I only clicked the "Level 2" button and it did everything to overlock..(you know I'm no overclocker) but i set it back to default on the next reboot so i don't know if that changed anything?

I see 664.7mhz..??

[kenroy112]

well with most memory modules you have to set the frequency from the BIOS manually

[MaxFactor1]

firstly its ddr so you multiply by 2 which puts you at approx 1333... so you must see 800 to be running 1600...

[M20]

Thanks,
How much of a performance difference if i set it to 800mhz? Anything else will be affected?

I also realise that when I used passmark to test my computer other people with 8GB of memory with same CPU and GFX cards' scores were much much higher than mine. It's like the 4GB crippling the system.. (win 64).. hmmm..