It is right. The RAM is most likely being bottlenecked by your processor. I'm going to go ahead and assume your processor has a 400MHz FSB (if quad-pumped). Before I explain it to you, I want to get it clear that DDR = Double Data Rate.
Ok, a quad-pumped processor is a processor that access the memory 4 times per cycle. So if it has a 400MHz FSB it would divide that into 4 to equally access the memory each pump during the cycle using 100MHz. Because DDR memory does 2 cycles for every cycle at the given speed it doesn't have to equally split the speed up to suffice for every pump. However you still need to take care of the 2 remaining pumps, so speed is cut in half to suffice for all 4 pumps. Therefore if you bought 400MHz RAM, at optimum level it could take care of 200MHz pumps. But because your processor only does 100MHz pumps, only half of that speed is utilized, and thus the principle of bottlenecking.
edit: Oh I guess I miss-read your question, your processor then is 800MHz, and the RAM is being utilized to its limit.