I have an older model acer aspire 500 mhz that I am using ,The unit at this time is running 1ea.pc100 168 pin 64mb and 1ea. pc133 168 pin 128mb .My question is when I remove the pc 100 and try to run just the pc133 it will not run,but it will run on the pc 100 by its self or it will run together.Someone told me that it might run faster with just the pc 100 alone because the pc133 is not able to run at its normal speed ,Should I be looking to buy more pc 100 ram only?The unit only has two slots for ram,
LMK Thanks
Rick

When you remove the pc100, move the pc133 to the slot where the pc100 was and then see if it will run. Some computers required that bank 1 (sometimes called bank 0) be used first.

when you combine pc100 and pc133, "theoretically" they both run at the slowest speed combined of the two, so in your case, they will both run at pc100 speeds. you won't see that much of a difference since you have a slower machine..

do move the ram as hank suggested..

The slots are numbered, such as DIMM 0, DIMM 1, and DIMM 2 etc... Choose the lesser, unused number. If this is the only module in the system, use DIMM 0 at all times.