Sunday, 15 February 2009

Memory upgrade for media center

I've noticed that my MythTV (Mythbuntu 8.10) machine was using 100% of its 1G and swapping. (Incidently, I was running the Blootube widescreen theme, and just switching to the MythCenter theme resulted in a snappier experience).

So, I went to buy more memory - and found that 1G cost AUD23 and a 2G stick was AUD45. Nice. I went for the 2G but when a friend commented that mixing a 1G + 2G I'd miss out on dual channel. Bummer, but I'll live with it.

When I first installed the RAM, I put the new 2G chip in the same channel (A) as the existing 1G. Booting the PC reported 3G in single channel mode, but it wouldn't boot! It simply reported a CRC error and stopped!

I took out the 1G stick, leaving just the 2G and booted okay. Hmmm, so now I put the 1G back, but in one of the channel B slots so the 2 sticks were in different channels. Now, when booting it reported 3G in Flex mode!

I'd never heard of this so I looked it up. It all gets explained very well here, and what it means is that I'll get dual channel access for the 1G stick, and the first 1G of my 2G stick, while the second 1G on the 2G stick is single channel. AWESOME! Thats just what I want! I don't have to have the same size memory sticks, but I can still benefit from dual channel when possible.

Incidentally, shortly after booting I used top to view whats going on - I saw that ALL 3G is being used and it is still swapping. Right now, it seems a bit better, with 900M free:

top - 08:26:58 up 16:53, 2 users, load average: 0.09, 0.11, 0.16
Tasks: 129 total, 1 running, 128 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.3%us, 0.2%sy, 0.0%ni, 98.7%id, 0.0%wa, 0.8%hi, 0.0%si, 0.0%st
Mem: 3088208k total, 2228644k used, 859564k free, 122452k buffers
Swap: 4883720k total, 5508k used, 4878212k free, 1397300k cached


I'm not just using this machine as a media center - I'm using it as a server, running some java apps and databases etc so it's not just MythTV running here.

(I'm using a Gigabyte GA965P-S3 motherboard, see the hardware page for more information).

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