Ram Decreased By Value

just got my pc back from technicial support at computer supermarket.com they replaced my motherboard and Hard Drive and as soon as i got it back i wanted to get back into my gaming... i had a few crashes with cod4 and was quite worried about my pc, as i had no problem running it before i sent the pc back for repairs... so, naturally i check the windows experience index to see if everything is ok. the graphics card was where it always was so it couldn't have been that. the ram has decreased by a value of 1.1 (from 5.9 to 4.8). surely the 4gb ram i had should have still been the same speed?