T440s up on Lenovo website (IPS Screen, 1080p)

Discussion in 'Lenovo' started by bdoviack, Jul 8, 2013.

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  1. JNavas

    JNavas Notebook Geek

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    With respect, the performance gain from dual channel memory is actually too small to notice in most cases (only a few percent), although it still makes sense to use it if possible.

    Realtek is poor in general in my experience -- I avoid it whenever possible.
     
  2. livebriand

    livebriand Notebook Consultant

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    But what about the iGPU? I seem to recall something about Intel platforms being able to use part of a RAM module to make some of the RAM dual-channel though, not sure what it's called off-hand. (Ex. 4GB + 8GB = 4GB + 4GB used for dual-channel, plus 4GB for single.)

    Seems OK for me, though I've had to turn off power-saving features in Device Manager to get the cards to work with certain APs (otherwise it frequently refuses to load things while claiming it's connected). Xirrus APs, for example.
     
  3. JNavas

    JNavas Notebook Geek

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    See Crucial FAQ: What is dual-channel memory?
    * Maximum gain is 10%. More typical gain is about 5%.
    * Benefit is in latency, not bandwidth.
    * Only works with pairs of exactly matched modules.
    * iGPU isn't a factor.

    I would not consider that "OK".
     
  4. livebriand

    livebriand Notebook Consultant

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    How is iGPU not a factor? I've heard of plenty of iGPUs (including the HD4400 in the T440s) being much faster with 2 RAM modules so that at least some dual-channel functionality works. If you're talking about the iGPU affecting the rest of the system, then sure, it's not a factor. And yes, excluding the iGPU, single-channel RAM doesn't make much of a difference.

    As for the power savings, yes, I'd like to not need that, but at least it works fine with that changed (though if they can't get it right to begin with, why bother trying?). The issue is rather reproducible though, both on my personal x120e and on the school's x120e, x130e, and x131e carts/labs, both under 7 and 8.x.
     
  5. JNavas

    JNavas Notebook Geek

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    Do you have any hard data to back that up? How "much faster"?
     
  6. livebriand

    livebriand Notebook Consultant

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    I thought I read that on the T440s, but at any rate, here's some benchmarks with the 4000 and 4400. (Obviously, I excluded AMD iGPUs since those are another thing entirely - though the APUs are known to be even more impacted with slow RAM.)

    Integrated GPU: Dual Channel vs Single Channel RAM - PC Message Board for PC - GameFAQs
    Benchmark: Single vs Dual Channel Ram with HD4000 Integrated Graphics (T430) - YouTube
    Performance and Scaling Overview of Intel HD Graphics 4000 - NotebookCheck.net Reviews
     
  7. JNavas

    JNavas Notebook Geek

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    In all three cases, 4GB single was compared to 8GB dual, making the results invalid.
    To be valid, the same RAM size needs to be compared in single and dual modes;
    e.g., 1x4GB vs 2x2GB.
    This is why relying on Internet data, even from supposedly reliable sources, is a risky proposition.
     
  8. optomechanical

    optomechanical Notebook Enthusiast

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    I measured 10-20% increase in crusader kings ii and diablo III by adding an 8gb stick. Cpu-z shows the memory running in dual channel mode. My fps in ck2 went from 25fps to 30fps which makes it totally playable without jitter (1600*900). I was skeptical at first but found someone who did a detailed analysis in spreadsheets of the increase on his HD 3000. Took the plunge and it paid off. I'll see if I can find it and link it.

    Edit:

    It was the hd4k here http://www.itsjustwhatever.com/2012...l-memory-for-your-hd4000-integrated-graphics/


    Sent from my SAMSUNG-SGH-I747 using Tapatalk
     
  9. JNavas

    JNavas Notebook Geek

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    As I've noted previously, changing the size of installed RAM means you cannot draw meaningful conclusions on single versus dual channel operation. To do that, you have to compare the same RAM size.
     
  10. Mr.Koala

    Mr.Koala Notebook Virtuoso

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    Are you implying that going from 4G RAM to 8G would automagically make your app run faster, even if it's not suffering from low RAM and not doing swapping to begin with? (I can't prove they were not swapping, but I have no reason to believe those benchmarks would full the RAM.)

    Edit: Looks like I can, at least for the itsjustwhatever.com article, as optomechanical has pointed out.

    Comparing 4G singe vs 8G dual means then can use identical RAM module(s), which is more consistent and eliminates potential differences between 4G and 8G modules. I understand that you prefer 4x1 vs 2*2 because in some real life situations as you might decide on the total RAM size first due to budget, and choose between single and dual later. But as long as the RAM space is enough for the test the comparison is valid.
     
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