Mixed Memory Question

I can't remember if it is going to harm the mobo if you mix memory speeds. We bought some memory for a computer PC133 is what the mobo maxes out at, but the old stick is PC100. Would it harm the computer if DIMM 0 is populated by the PC133 and DIMM 1 is populated by the PC100 stick? It's running XP so I'd like to up the memory from 256, but it's better than the 128 that it originally had.

Thanks for any help.

 

it shouldnt harm it, but it WILL run both of the sitcks at the lower ones speed, in this case, PC100.

 

Yes, thats absolutely correct but you are better of having lets say 1x512 rather then 2x256 also.