mcclnx mcc wrote: > we have DELL 6800 server with 20GB RAM in it. We like > to expand it to 64 GB. I checked Redhat web site and > it say max memory is > "Architecture & system dependent". > > Does anyone know what is Max RAM Redhat CENTOS 4.3 (32 > bits) support? > I would -STRONGLY- suggest running x86_64 (64bit) on any system with over 8GB of ram if you truly want to be able to use it properly. PAE has an absolute upper limit of 64GB, but the PCI bus and its devices need about 1GB of that. I seriously doubt a 32bit system would get any more mileage out of 64GB than 20GB ram due to the 4GB addressable address space, and the size of the resulting page tables.