Mixing PC100 and 133 RAM

There are no specific error messages. Either it works or it won't work. If you have noticed differences in the machine since you mixed the memory then that most likely is the case. Most of the time mixing the memory does work but I have also seenit not work.

The 'errors' are possibly hardware or software dependent. Many systems will support both types together, with no 'messages', but only at the PC100 speed. The hazard is when your system dynamically allocates resources (as it does all the time) and the different RAM doesn't behave. You may get an error message from the application, you may just get a lockup or something else 'odd'. The unpredictability of the problem (when and if) is the reason for the caution.

there's really no good reason why pc100 and pc133 memory can'y be mixed. essentially, pc133 is only an higher-clocked version of pc-100. mixing memory of different voltages or different architectures can cause problems. since pc-100 and pc-133 both have serial presence detect chips, they should work togerther well.

I just put two 128MB PC-133 DIMMs in my Compaq that also has one 128MB PC-100 DIMM (total=384MB). The machine appears to be running just fine. Performance has increased just the way I expected it to (lots better on memory intensive apps and sorta better on those that don't need lots of memory). As of last night, it had been running for 5 days with no problems (which is pretty good for W98!)
As always: YMMV (Your Mileage May Vary)

Hope this helps...

I've found that recent systems have a much easier time handling various memory speeds (ie mixing PC66 w/ PC100 or PC100 w/ PC 133). The newer memory will underclock itself to match the slowest memory installed. "Back in the old day", when memory wasread in 80ns, 70ns, and oh my 60ns, things were a little different. You could get away with about a 10ns difference between SIMMS, however, if you went too far past that memory problems would occur (anything from not booting to losing random bits ofdata). Currently I'm running PC2100 and PC1600 DDR DIMMS together and the only thing I had to do was manualy update my bios to alter the lateny click. Hope this information helps.

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