Win not recognizing memory!

[tellsek]

So I just built my new machine, athlon 64 (939) 3000+ OC to 2.4 Ghz. I have a 512 stick of memory that winXP is only recognizing as 256. I checked the stick and every other diagnostic I run shows it as at 512. Any ideas why windows is only recognizing it at 256?

 

[mikecel79]

Try running memtest on it and see if you are getting any errors. Are you sure it's showing up as 512MB in the BIOS?