Linux wrote: > You are missing the point about the bug in some Intel chipsets. > http://www.google.com/search?q=intel+chipset+kernel+4gb > or the lack of support in 5.1 for ICH9 in non-AHCI mode which means the OS won't even install, never mind 4GB+ memory issues. so, really there's four completely separate issues here... A) Intel desktop chipsets don't support 'memory remapping' so somewhere between 750MB and 1GB of RAM is physically inaccessible on a machine with 4GB+ memory, no matter WHAT you do in software. This 750MB-1GB of inaccessible memory is at the same address as the PCI and PCI-E busses. In a pure 32bit environment, this all has to fit in the first 4GB. B) many Intel desktop chipsets have a maximum 4GB physical memory limitation anyways, which when combined with A) means 3-3.25GB usable memory. C) 32bit systems with > 4GB memory require PAE support both in the CPU and in the operating system... /all/ Intel CPUs since about Pentium Pro have this. For systems with > 4GB ram, you probably want to run 64bit native rather than mess with PAE anyways. D) out of box support for the chipset and its peripherals so the OS can be installed without having to dink around with special flags or add-on drivers. The newest ICH9 and ICH9-R chips ARE supported in 5.1 if they are in ACHI mode, but apparently Intel has leaned on motherboard makers to not support AHCI mode on ICH9 in the BIOS, only on ICH9-R (which is the same basic backend chip with fake-raid enabled). your 'bug' is issue A). I think its more a design feature or side effect, not an outright bug, but thats a nomenclature thing.