Pc slow than it was

[ibotnaru64]

HI, when i wanted to repair my pc i said to the man i want 8 gb ram (i had 4gb), then he said ok. The older ram(4gb) it was 800mhz, but now i have 8gb and it's 667mhz and i don't know why but the computer is slower than it was. pls help

 

[rgd1101]

full system spec? return the ram and get 8gb 800mhz

 

[ibotnaru64]

full system spec? return the ram and get 8gb 800mhz

CPU: Intel quad core q8200 2.33ghz
GPU: palit gts 450
240gb ssd (installed windows on it)
500gb hdd
mobo: asus pq5-pro
ram 8gb ddr2 667mhz
i had 4gb ram 800mhz like i said
so, it would slow the 8gb ram than 4gb ram?