Check the BIOS POST memory counter and make sure that all of the RAM is showing up in that test. Sometimes the BIOS is set to enable quick boot (which skips the memory test), so you may need to turn off that quick boot to enable POST test. Unfortunately no speech for these. If you are using grub, by default grub passes a mem= parameter to the kernel and sometimes gets it wrong. You can disable grub's doing this and let the kernel decide how much memory you have by adding the --no-mem-option flag in the kernel entry in /boot/grub/menu.lst kernel --no-mem-option /boot/kernel root=/dev/hdXX You don't need the high mem support in the kernel, that's for mem over 2GB I think (or something like that). It definitely works with 512MB without it turned on. You might consider swapping those 128MB DIMMs in one at a time to see if they both are working. Sometimes programs like lm_sensors will see a RAM module but the system will not. I recently bought a 512MB SO-DIMM and only 256MB was showing up. The smbus type stuff in both windows and linux said it was a 512MB SO-DIMM but it was defective, only half of the RAM was working. Had it replaced and the new one worked fine. One of your DIMMs might be bad. Also, as suggested, read your motherboard manual, sometimes there are rules about which banks can be used and in which order etc. -- Doug
