You would have to look up in your manual or on line what the max memory supported by your motherboard is. If it can be expanded, sometimes you will need to replace all the current. example if you have 4 and can support 8 chances are you have (2) 2gig modules. You would need to buy (2) 4gig modules. You just need to make sure you buy the right ones. Check the number of pins and speed needed for your specific model.