(solved) Max memory for a core i7-2630QM

<3 · Veteran Joined: 21 Oct 2004 Posts: 1085

Hello all, I have an older Intel Sandybridge based laptop that I received as a gift in 2012. While the mobile CPU that is in my laptop quite a few generations outdated it still gets the job done. It has a 8 core (4 physical + 4 logical) CPU intel I7-2630QM mobile CPU inside. I don't see a need to buy a new laptop to replace this one as it is fast enough to handle most of the things that I throw at it, I am not gaming on it nor am I doing any multimedia encoding. The main thing that I do want to improve is the fact that compiling qt-webkit/chromium/blink takes forever and is probably killing my SSD with the many writes to swap. The easiest way to fix this issue is to increase ram and since ram prices have dropped I thought now would be a good time to purchase ram. For some stupid reason the laptop manufacturer equipped my laptop with a 4GB and a 2GB stick (6GB total) of ram ensuring that the ram runs in single channel mode (why?!?!?!?!).

Ideally I would like to get 2x 16GB sticks of ram for a total of 32GB system ram. I was surprised to see that Intel listed this CPU has supporting a maximum of 16GB of ram which seems a bit odd, especially for a CPU that was aimed at higher end laptops when it was released. Also that wording of that spec is a bit ambiguous (is 16 that max total memory or the maximum sized ram stick that will work with the CPU?). I am hoping that I am misunderstanding this website and that the 16GB is the maximum amount of memory per channel. Can someone please help me to understand if that limit is per channel or the total maximum memory that this CPU supports. 16GB seems arbitrarily small and I will be thoroughly disappointed if 16GB is really the total maximum that this CPU supports.

eccerr0r · Posted: Tue Feb 18, 2020 12:12 am Post subject:

I build on my i7 with 8GB RAM, and it doesn't swap that much, likely you aren't swapping with 16GB, and will need a faster CPU, distcc or whatever, to decrease your build times -- not RAM.

Yes the CPU itself will limit how much RAM you can use because the memory controller is inside the CPU in these "newer" machines.
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Hund · Apprentice Joined: 18 Jul 2016 Posts: 220 Location: Sweden

It's 16 GB in total, which is plenty enough.

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<3 · Veteran Joined: 21 Oct 2004 Posts: 1085

thanks, I hope 16 is enough =( I was going to go and get 2x 16GB sticks since memory prices have fallen but I guess I'll have to settle for 2x 8GB sticks. I wonder why Intel set such a low memory capacity for one of their higher end (at the time of release) mobile CPUs.

mike155 · Posted: Wed Feb 19, 2020 2:52 am Post subject:

<3 · Veteran Joined: 21 Oct 2004 Posts: 1085

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eccerr0r · Posted: Thu Feb 20, 2020 4:00 pm Post subject:

More likely they were just tossing in extra waste memory they had lying around to make the specs of the laptop seem better... to most people two laptops with the same specs and one had 6GB and another had 4GB, which would be chosen?

Oddly enough onboard graphics works better with dual channel enabled too, anyway.
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Jaglover · Posted: Thu Feb 20, 2020 4:02 pm Post subject:

I have at least 20 of those 2 GB laptop memory sticks ... now all I need is laptops, right?

(Probably that manufacturer also had lots of 2 GB sticks laying around.)
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eccerr0r · Posted: Thu Feb 20, 2020 4:15 pm Post subject:

You need to find a laptop that has 20 DDR3 (or whatever) slots

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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
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<3 · Veteran Joined: 21 Oct 2004 Posts: 1085

In case anyone was interested....

So I went ahead and purchased the 2 8GB memory sicks. So in addition to going from single channel memory mode to dual channel memory, I more than doubled my system ram. Because of this I was able to switch the MAKEOPS back to -j9 from -j3. Emerging very large packages with -j9 and only 6GB of ram make the computer almost unusable. Now with the added ram I was able to change the MAKEOPS back to -j9.

I was hoping that the added ram and switching to -j9 would have a more dramatic decrease in compile time for large packages like qtwebkit. It did help though not as much as i'd like, still I was able to prolong the life of my 8 year old laptop with a simple and relatively cheap ram addition so I am grateful for that.

Here are my new compile times for qtwebkit before and after the ram upgrade and the with the change to MAKEOPTS=-j9 (also I have ccache installed so I don't know how much of an impact that may have had).