Combining PC100 and PC133 SDRAM

germanaman

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Aug 4, 2006
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I've got an old ASUS CUV4X-D motherboard with dual PIII 1GHz with 133 FSB and 1GB of PC133 SDRAM. I have some extra SDRAM laying around from other computers, but its PC100. I was wondering if I could combine PC133 and PC100 RAM on this motherboard, or even just in general would it work? I figure that the PC133 modules will just drop down to 100MHz, but not sure if that'll mess with the FSB speed of the processor. I'm not really worried about having slightly slower memory speeds because I not really using the computer for anything major, probably just some home server stuff with Linux.
 

caamsa

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Apr 25, 2006
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If you are running your FSB at 133 you will need to use 133 memory. You might get lucky and some of the pc100 might work at 133 but I doubt it. If not lower the FSB to 100 and use the pc 100 memory if you have more of that.
 

strpdgato

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Mar 20, 2006
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I have a PIII box w/ one sick of 133 and another 100 and it has been working fine [for years] (intel chipset btw) . I guess the FSB adjusted it's self accordingly.
 

Slappy_Slime

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Oct 22, 2006
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from what i heard years ago, that when ya mix different ram together, ya put the slowest (pc100) in the first slot then go from their. from what the man told me was the slow mem will slow down the faster mem. in other words the (pc133) will get pulled down to (pc100). but if ya do it the other way it will cause the pc to crash(or be unstable). ive got mixed ram on my server with no problems. "ga-5ax w/amd 450 w/ 3 sticks totaling 384 meg ram, running bsd". :D O-yea the bios is set to defaults.