(Apologies for the SEO bait title; this info took me forever to find, so I’m leaving it here for others who might have the same issue).
My desktop computer is getting old. I got it in March of 2008, which in computer years makes it roughly 72. Over the years, I have replaced/added hard drives, a bluray drive, sound and video cards and the like. So all things considered, it functions at least as well as a modern off the shelf unit. The only downside has been the RAM. It came from the factory with 2GB installed, decent enough in its time but pitiful by today’s standards. Things have gotten bad enough that I can barely do any work in either Windows or Ubuntu without running out of RAM.
So, when I came into some extra, cheap RAM sticks, I happily installed them to get a total of 6GB. According to a rep at Dell, the motherboard (an Inspiron 530) could accept up to 8GB, so I figured this was fine. After installing and booting up the system, the BIOS indicated that all 6GB were present and working correctly. I happily booted into Ubuntu to test everything out, but it was as slow as ever. Running “free -m” gave me:
total used free shared buffers cached
Mem: 2757 2080 677 0 202 779
-/+ buffers/cache: 1098 1659
Swap: 15999 0 15999
Which means only about 2.7GB was available of the 6 I am supposed to have. Googling didn’t help; most message boards and blogs focused on the 4GB memory limit of 32-bit operating systems, and the Linux PAE module that is supposed to help fix it. Since both my operating systems are 64-bit, this advice didn’t help. I also tried “sudo dmidecode” (dmidecode is a tool for dumping a computer’s DMI table contents in a human-readable format), but that didn’t help either. Running Memtest86+ found no errors in any of the available sticks.
I read the Dell documentation about the motherboard and found that my model, the 503, can only support up to 4GB of RAM, while the other versions (like the 503s) can support up to 8GB. This still didn’t explain the missing 1.3GB and it conflicted with what the Dell rep had told me. I kept looking around for a third party reference of how much RAM the board would accept. Finally, I found this wikipedia article that states:
[The Inspiron 530] has 2 GB of DDR2 SDRAM at 800 MHz, which can be upgraded up to 4 GB (slandered bios)or 8GB (bios upgrade 1.0.18 needed). The desktop has a 320 GB 7200 RPM Serial ATA hard drive w/DataBurst Cache, which can be upgraded to 1 TB….
It turns out I was using BIOS version 1.0.10, so I was a bit behind. I was able to find the 1.0.18 BIOS upgrade on Dell’s site and flash the ROM. After rebooting, running “free -m” gave me:
total used free shared buffers cached
Mem: 5969 2574 3395 0 117 855
-/+ buffers/cache: 1600 4368
Swap: 15999 0 15999
Success! Ever since figuring this out, I haven’t had any more issues with running low on RAM. In fact, the computer is running smoother than it has in a long time. Boom! Next on the list: replace the two 1GB sticks with two 2GB sticks and max out at 8GB total RAM. (Not setting any records or anything, but I plan to run this motherboard until it dies).