"Acer Ferrari 3400" has 2 Memory Slots. Each slot has a max memory limit of 1GB which gives a combined max memory of 2GB for the machine. You can simply add extra module of rams up to 1GB to the empty slot(s) or replace your current one with the higher sized modules. We recommend ordering as matched pair to achieve dual channel speed (twice faster on the same frequency). We always send matched pairs for quantities more than one.