memory for G41

[ossadtchi]

I need a lot of memory to fit all experimental data in ram for faster processing. There are two ways,

1. buy with minimal configuration(256MB) and then get a 1 GB single slot memory from somewehre else (1,25G is ok for the beginning)
2. Order and configure it with 1 G from IBM and sleep soundly....

If I decide to go along #1 , and decide to get 1GB PC2700 CL2.5, say from zipzoomfly for $220(thanks, dfumento!) will it work for the G41?
I am especially concerned with mixing IBM memory with the one I'll buy.

Thanks!