Processor | Physical Address Limit |
---|---|
32-bit P* | 4GB |
32-bit P* with PAE | 64GB (limited by mother board) Note that PAE-accessed memory is slower than the first 4GB of RAM (however it is still hugely faster than disk) and some kernel structures must live in the first 4GB of memory, so you might exhaust this "low" memory before you exhaust all of your RAM. |
64-bit CPU | effectively unimited (except by mother board and your ability to pay) |
CPU Type | Process Limits |
---|---|
32-bit CPU | 4GB (1GB kernel/stack; 3GB user use) There are allegedly some patches out there which can fiddle with this ratio. |
64-bit CPU | effectively limited only by RAM/Swap and your ability to pay for memory for your machine |