There are several classic problems related to memory on Linux systems. 1) There are some buggy motherboards which cannot properly deal with the memory above 16MB. Consider exchanging your motherboard. 2) You cannot do DMA on the ISA bus to addresses above 16M. Most device drivers under Linux allow the use of bounce buffers which work around this problem. Drivers that don't use bounce buffers will be unstable with more than 16M installed. Drivers that use bounce buffers will be OK, but may have slightly higher overhead. 3) There are some motherboards that will not cache above a certain quantity of memory. If you have one of these motherboards, your system will be SLOWER, not faster as you add more memory. Consider exchanging your motherboard. All of these problems can be addressed with the "mem=XXXM" boot option (where XXX is the size of RAM to use in megabytes). It can also tell Linux to use less memory than is actually installed. See the documentation of your boot loader (LILO, loadlin, etc.) about how to pass options to the kernel. There are other memory problems which Linux cannot deal with. Random corruption of memory is usually a sign of serious hardware trouble. Try: * Reducing memory settings in the BIOS to the most conservative timings. * Adding a cooling fan. * Not overclocking your CPU. * Having the memory tested in a memory tester or exchanged with the vendor. Consider testing it with memtest86 yourself. * Exchanging your CPU, cache, or motherboard for one that works. * Disabling the cache from the BIOS. * Try passing the "mem=4M" option to the kernel to limit Linux to using a very small amount of memory. Other tricks: * Try passing the "no-387" option to the kernel to ignore a buggy FPU. * Try passing the "no-hlt" option to disable the potentially buggy HLT instruction in your CPU.