My 333mhz ram only running at 320. Why?

[Oyeve]

Hi all. I have an Asus P4P800 Deluxe with a P4 3.0ghz 800fsb cpu and 1.5 gigs of pc2700 (333mhz) ram but the bios says it is running at only 320mhz. If I go into the bios settings the only options I have for ram speed is auto, 266, 320, 400. What is the bottleneck? Does the cpu need 400mhz ram to run better? Why cant I utilize the 333mhz at 333mhz speed?

 

[Accord99]

Originally posted by: Oyeve
Hi all. I have an Asus P4P800 Deluxe with a P4 3.0ghz 800fsb cpu and 1.5 gigs of pc2700 (333mhz) ram but the bios says it is running at only 320mhz. If I go into the bios settings the only options I have for ram speed is auto, 266, 320, 400. What is the bottleneck? Does the cpu need 400mhz ram to run better? Why cant I utilize the 333mhz at 333mhz speed?

If you have a 800MHz FSB P4 and only 333MHz capable memory, the motherboard will use a 5:4 ratio between FSB:memory which results in 320MHz for the memory bus.

 

[txxxx]

Whilst on the topic, is there much real world impact between dual channel ddr333 and dual channel ddr400 for P4's?

 

[Oyeve]

Originally posted by: txxxx
Whilst on the topic, is there much real world impact between dual channel ddr333 and dual channel ddr400 for P4's?

Not really. I raan Sisandra and when I matched it up to other systems with 333mhz mine did pretty well in the scores. I was more concerned why it wasnt running at its rated speed. So if I get 400mhz will it run at 400? Or is this the best I can achieve right now?