PC800 RAM and FSB speed

Hi,

I am trying to upgrade my RAM. My computer uses RDRAM, specifically PC800. The 1GB kits seem to come in two speeds, 40ns and 45ns. I saw a short line somewhere that said that 533 MHz FSB should be accompanied by 40ns RDRAM. I have a Dell PC, and have checked out the BIOS where there are NO FSB settings or displays. How can I tell through softwarae what my FSB speed is, and does it matter regarding the 40 or 45ns memory speed? Thanks.

First off, 40ns RAM will always be better than 45 (although depending on the way you use the computer, you may not notice the difference). Second, an easy way to tell your fsb speed is to download CPU-Z from http://www.cpuid.com/cpuz.php and (im assuming you have an intel because of the rdram and bus speeds) look on the CPU tab in the lower left for "Bus Speed" that will tell you your speed (400, 533, 800MHz) and you can look through the program and get lots more info on your PC.

Shotz, thanks for that great link. I just tried the program out here at work, and it looks like that will tell me everything I need to know, that the Dell BIOS keeps secret from me.

You said that 40ns is always better than 45ns, which I can certainly believe. I checked out my RAM in the machine now. I have 4 128MB sticks now, and at least the 2 original sticks are 40ns. The two others are a PNY upgrade (neither the sticks nor the PNY website show the speed). Right now, my most important question, is... Do I have to have 40ns RAM if my machine is a 533MHz FSB? In addition, if I don't have to use 40ns RAM under any condition, what is the performance hit? As you probably know, new RDRAM is ridiculously expensive. I have been shopping ebay for used RDRAM, and 45ns seems to be the most common. ANy further advice or reference sites you could point me too would be much appreciated. Thanks.

You need 40ns pc800 ram (or faster) with the 533mhz FSB.