Memory issues

I just recently bought 4GB of Mushkin ddr2 1000 for a new build.
Put it in, booted it, but it's only showing at 3.25GB..?

I have an GIGABYTE GA-EP45-UD3P mobo

In my other system I put 3GB in and all 3GB showed up..

Is it a memory fault.. or what do I do to make it a true 4gb?

I'm computer savvy, but not overclock/voltage/etc savvy whatsoever.

Thanks

 

If you're running XP, that's the most you'll get. Period. It's an OS limitation.

 

Weird, cause there wasn't a limit when I had a 2gb stick and 2 512mb sticks.. weird.
thanks though.

 

Not wierd...2GB+512+512=3GB. Upgrading to XP64/Vista64/Windows 7 x64 (recomended) will get your memory.