Had exactly the same issue on Dell Desktop ~4 years ago (dont recall the specifics).
I upgraded the BIOS, but still it was the limitation of the BIOS to present the 4GBs to OS. After loading up PAE kernel running Fedora 6 with some tweaks, i was able to get more memory from the box. Initially i had 3.3 and it went to 3.7GB. Long story short, it was vendor/model specific issue for me and not so much kernel/OS. ________________________________________ From: [email protected] [[email protected]] On Behalf Of Jonathan M. Polom [[email protected]] Sent: Monday, May 09, 2011 2:54 PM To: Red Hat Enterprise Linux 6 (Santiago) discussion mailing-list Subject: Re: [rhelv6-list] RHEL6 x86 on system with 4 GB memory On Tue, May 3, 2011 at 8:26 AM, Jonathan M. Polom <[email protected]> wrote: > On Tue, Apr 19, 2011 at 2:58 PM, Steve Allen > <[email protected]> wrote: >> "Jonathan M. Polom" <[email protected]> wrote: >>> I have Red Hat 6 x86 installed on a Pentium 4 system with 4 GB system >>> memory. Although the default kernel has PAE capability (no modules in >>> lsmod but it's a requirement for the x86 variant so it's likely >>> compiled in) it claims total system memory is about 3.3GB (via top or >>> gnome performance monitor). How do you get RHEL6 to see >= 4GB memory? >>> Is it a kernel argument or something else? >> >> PAE has to be enabled in the BIOS. If you don't have that option in the >> BIOS, you just can't do it. I'm in the same position, 4GB RAM, but no >> PAE in the BIOS, so all I get available is about 3.3GB. >> >> Steve >> >> _______________________________________________ >> rhelv6-list mailing list >> [email protected] >> https://www.redhat.com/mailman/listinfo/rhelv6-list >> > > Didn't think to check the BIOS. Will do. Thanks. > > -- > Jon Polom > Sorry for resurrecting a dead thread but I just rechecked this issue. The BIOS reports 4.0GB of memory installed but doesn't appear to have an option to enable/disable PAE. So perhaps PAE isn't supported by the BIOS? Or PAE is enabled by default. This is something I need to check with my system vendor, however it still seems odd. Why would the BIOS report 4.0GB of installed memory without being able to use all 4.0GB? A colleague mentioned that it has to do with how the BIOS calculates installed memory: installed memory size is calculated by the BIOS by taking the difference between the highest and lowest memory addresses. Is it typica for a BIOS to report 4.0GB (beyond the 32bit max address without PAE) yet not support PAE? Thanks, Jon _______________________________________________ rhelv6-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv6-list _______________________________________________ rhelv6-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv6-list
