View Full Version : Quick Memory Question

04-06-04, 08:50 PM
I have an old P3 450 system and I was wondering which is better....

Run 128 sdram at 100mhz
Run 256 sdram at 66mhz

The computer is just a spare, but I was wondering which scenario is best. I have two sticks of 128, but one of them is a 66mhz stick. Am I correct in thinking that even my 100mhz will run at 66mhz if I add the slower stick? Thanks.

04-06-04, 09:00 PM
yes in all likelyhood rhe slower speed will be used as deafault

04-06-04, 09:26 PM
Yes, 100 sticks can downclock to 66 but not vice versa. Also, if I read your question correctly...Run 128 sdram at 100mhz
Run 256 sdram at 66mhzI would go with the 256 stick even though it is 33MHz slower...you won't notice much diff with 33MHz bump but will notice the 128MB increase. Good luck. :)

04-06-04, 11:53 PM
um, a P3 450 does not run on a66mhz bus, it's a100 only chip... the mobo will attempt to oveclock the 66mhz ram to 100, which will probably work just fine...

If that was a Celeron, we'd be talkin bout the 66, but that's not the case here...

and btw, in those classes of system, 100mhz bus vs 66mhz is in fact a heck of a difference. Run a celeron around 366-600 @ 66mhz, then do the same with a 100fsb P2 or P3 and you'll see...


04-07-04, 04:26 AM
Yeap thats 100% correct Pentium 2/3 350MHz onwards use 100MHz FSB. The P3 450's use 100MHz FSB!

04-07-04, 06:43 AM
The fact is I was thinking the bios will detect the SPD readings whatever of the memeory chips, If one stick is 66 MHz and the 100MHz, I was led to belive that the bios will choose the lower of the two (safegaurds), ie 66MHz to run the memory. There is probably a divider that gets automatically called for. u can run 100mhz fsb cpu with 66mhz sdrams asynchronously.

04-07-04, 07:51 AM
Thanks for all the help so far. So don't even bother just running 128, go with 256......Will this cause any problems at all. The system runs fine with the 256 installed right now. Thanks.