Hi, I have an Acer Aspire 2191 computer. It is upgradeable to 256MB of RAM via 2 DIMM sockets. It uses 168 pin SDRAM modules. The question is I don't know whether they are PC 100 or PC 133? Can anybody help me figue this out? Thanks

here is a link to the type of memory you need. it is at the crucial.com website http://www.crucial.com/store/listparts.asp?Mfr%2BProductline=Acer%2BAspire&mfr=Acer&cat=RAM&model=Aspire+2191&submit=Go

I checked my system with belarc advisor and it shows that it is 66mhz! Can 100mhz or 133mhz be used in my system?

100 mhz yes 133 mhz usually

Oh and there's a good chance your bios won't recognize a 256 meg stick of memory. Check the manual. You may need to use 64's or 128's.

Thanks I will try the 100 mgs of ram. This system has 2 slots that each take 128mgs max each.