• Registered: 2011-03-02
  • Posts: 9

Topic: Any RAM gurus here?

My system normally runs 1x 1GB bank and 1 x 512 MB bank of RAM running asymmetrically. I tried to locate another 512 MB bank I thought I owned, but could not locate. (I'm now questioning whether I indeed own another, or if it's a 'Twilight' case of wishful thinking, nevertheless). The reason for this search was to see whether 2 x 512MB banks running interleaved would make an appreciable difference to my system.

Seeing that I was unable to test this for obvious reasons, I decided to remove the 512MB bank and run just 1 GB of RAM in single mode and see what the result was.
I must say I was shocked! My system 'seemed' more responsive with memory usage dropping 10% (49MB down to 44MB@idle), but fan speed increasing from 1200 RPM to just over 1900 RPM.

I would have imagined that the best results would have been 2 x same size banks running interleaved, followed next by 2 x different size banks running asymmetrically, and lastly 1 x bank running in single mode. However such is not the case so it seems.
The change in fan speed I cannot explain.
Thoughts?

  • pitje
  • #! Junkie
  • Offline
  • From: me to you
  • Registered: 2009-02-10
  • Posts: 401

Re: Any RAM gurus here?

I really have no idea if it's correct, but to me it seems that when you use one bank of RAM, you're using one 'path' from RAM to RAMBUS (CPU) and to the North Bridge.
When you're using two banks, the traffic is less 'busy' (you're using 2 paths), but it can be that, due to timing differences in bot the RAMs, some actions have to wait for other actions to complete (hence the fact that your computer feels more responsive with less RAM)
The change in fan speed would be due to the fact that more traffic goes over 1 path => more heat generation.

But again, I'm anything but a RAM guru, and the above is just speculation smile

laptop: asus zenbook UX31 [debian wheezy, kernel 3.3.0-rc7-custom]
tablet: acer iconia a500 [honeycomb]
home: C2D E8500, 4GB RAM, 74GB Raptor HDD + 2.5TB in various HDD [debian squeeze, liquorix kernel]

pitje's Website

  • Registered: 2011-03-02
  • Posts: 9

Re: Any RAM gurus here?

@pitje
Thanks for your reply. I must say I am a little confused by this.
Firstly the banks as far as I know have the same bus speeds. Though you may be correct, perhaps they don't. Must check that...
Secondly, my understanding is regardless of RAM size or speed, the cpu will always be waiting, whether writing to or reading from RAM.
Now I could be wrong...

  • pitje
  • #! Junkie
  • Offline
  • From: me to you
  • Registered: 2009-02-10
  • Posts: 401

Re: Any RAM gurus here?

please don't let my ramblings confuse you, they're just a few thoughts I got when reading your post smile
I know just a little bit about the internals of my computer, but that's just the mere basics.
I'd say the possibility of me being wrong about this is pretty high big_smile

laptop: asus zenbook UX31 [debian wheezy, kernel 3.3.0-rc7-custom]
tablet: acer iconia a500 [honeycomb]
home: C2D E8500, 4GB RAM, 74GB Raptor HDD + 2.5TB in various HDD [debian squeeze, liquorix kernel]

pitje's Website