Hello, I have a PC, It has origionally a Hynix 512 MB RAM in it, I then put an apacer 1GB PC5300 Stick in , same as the other 512 MB stick. the 1GB stick won't recongnise and and It reads as 900 MB on startup, I even swaped out RAM slots and it won't operate without the 512 MB stick in. the ram is not faulty as I checked it with another system.
check your mobo specs that how much ram it support in one stick
it says it can support 1 GB per stick with a max of 2GB