Hello, My system is compaq presario SR1630il. OS-windows XP PRO sp2 At present I am having 512MB RAM. I want to upgrade to 2GB(maximum possible for this model). The product specification Base processor -- pentium 4 519(p) 3.06GHZ,533MHZ front side bus,socket 775 chipset Intel 915GV motherboard -- msi--MS-7174 HP/compaq motherboard graphite-GL8E MEMORY memory installed--256MB(1x256) memory allowed 2.0GB(2x1GB) speed supported -- pc2-3200MB/sec Type--DDR2 SDRAM DIMM slot -TWO open DIMM slot--one so I want to increase the ram capacity to 2GB(2x1GB) The HP tech support people say that I have to purchase two 1GB DDR2 SDRAM 400MHZ. But the local retailers said two 1GB DDR2 SDRAM of 533MHZ or 667MHZ can be used kindly advice me the exact specification for purcaseing the RAM. kasinath.