S there a difference between ddr2-800 128mb and ddr2-800 pc6400 memory

[crazyg]

I'm attempting to upgrade memory from 6GB to 8 and wish to replace two 1gb DDR2-880 sticks with 2GB ones. I found these 128MB modules on ebay along with other pc-6400 at a lesser price but don't know if they will work or make a significant difference, Thanks for any info
crazyg

 

[jaquith]

Welcome to Tom's Forums!

Frequency is only part of the equation, you need to match both the CAS Timings and Voltage to the 2X2GB kit already installed. Ideally, the same exact part-number if going to 4X2GB is the safest option.