Yes, since they are both 184pin sticks of ram they will work but be aware that they will both run at the slower speed 333mhz of the pc2700 ram. If your motherboard is DDR capable you would get the best improvement by getting a second stick of identical 400mhz ram and running them in Dual configuration, this would allow for both sticks being accessed at the same time (dual data rate). See your mobo manual for where to place the two sticks to get the DDR function.