GTX 970 VRAM (update: 900M GPUs not affected by 'ramgate')

Discussion in 'Gaming (Software and Graphics Cards)' started by Cakefish, Jan 23, 2015.

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  1. Zero989

    Zero989 Notebook Virtuoso

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    Well

    Gigabyte
    Amazon
    eVGA
    OC.uk
    Newegg

    Are all refunding some users.

    Waiting on MSI/ASUS

    The damage is done.
     
    Last edited: Feb 2, 2015
  2. tollingalong

    tollingalong Notebook Enthusiast

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    The part that doesn't make sense is the dGPU is being tested. Windoze writes it's graphics data to the iGPU (unless otherwise configured). The CUDA tests are hitting the gGPU hence the 500MB should have nothing on it unless Nvidia caches the iGPU data as well. For sake of argument let's say there is 500MB of data in gGPU cache. Why would everyone's benchmark hit a snag at 500MB (even headless ones which don't write cache to the 500MB block). On clean machines with low amount of eye candy people should be hitting the problem post 3.5GB mark or a 4GB card.

    Your explanation makes sense using exclusively the dGPU as a main card. Either way I won't be able to verify this until my 980M comes to my house.

    BTW
    I think most people don't seem to realize at the end of the day the problem is minor for most gaming.
     
  3. Cloudfire

    Cloudfire (Really odd person)

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    GTX 980M have the exact same setup on the DRAM/MC as GTX 980. The only thing thats disabled there is SMM :)
     
  4. James D

    James D Notebook Prophet

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    Man, can you just trust me that You Are Wrong? Or I have to post some video explaining that in details?
    Before doing that I will try to write shortly in words and pictures: that L2 cache can't work simultaneously with 2 Memory Controllers It just stripes between them hence why all this problem appeared! There is no "L2 section has more stress on that, but the GPU is still a 256bit card" there is "... hence why GPU is 224 bit card".

    Just look at the comparison after all!
    Watch that GTX 980 has 178+GB/sec while GTX 970 has 150+GB/sec which is exactly 7/8th of speed . That's because it is BS that 970 can use all 8 MC at once filling GPU vRAM. Because only 980 is 256 bit card where 32bit*8MC with 224GB/sec theoretical bandwidth.
    [​IMG]

    So after you finaly found that in Maxwell you need to count not just MC but MC-L2 lines will you ask forgiveness for "lot of clueless people saying you have 192GB/s if you use the 3.5GB memory bank and you get a lot lower speed when using the last 0.5GB"?
     
  5. R3d

    R3d Notebook Virtuoso

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    From PC Perspective:
    "UPDATE 1/27/15 @ 5:36pm ET: I wanted to clarify a point on the GTX 970's ability to access both the 3.5GB and 0.5GB pools of data at the same. Despite some other outlets reporting that the GPU cannot do that, Alben confirmed to me that because the L2 has multiple request busses, the 7th L2 can indeed access both memories that are attached to it at the same time."

    Though given Nvidia's recent spotty record, they could be mistaken again. IMO there needs to be more testing done to confirm/deny this.
     
  6. James D

    James D Notebook Prophet

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    Sure 7-th LC2 can act with 2 MCs at once... but presumably with the same overall bandwidth as other LC2 act with their one MC.
     
  7. HTWingNut

    HTWingNut Potato

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  8. Mr.Koala

    Mr.Koala Notebook Virtuoso

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  9. Cloudfire

    Cloudfire (Really odd person)

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    OMG, I give up. People can`t read.
    Nvidia is lying. Its a cover up.

    The benchmark read 7/8th of the 980 speed because it accessed only the 3.5GB portion. That is the total bandwidth they gave. Then it got 1/8th of that on the 0.5GB when it read that.
    Nvidia specified that programs and games can access both SIMULTANEOUSLY. Through the 7th L2 cache. Which is why VRAM usage can go up to 4GB and which is why it is a 256bit card (32*8) and have 224GB/s bandwidth (all 8 memory controllers together).

    Why is this so hard to understand?
    The change from the original specifications from Nvidia is 1.75MB L2 cache instead of 2MB since one is disabled. And it have 56ROPs instead of 64ROPs you find on GTX 980.
    So you have less ROPs than 980, more strain on the 7th L2 cache that needs to access 2 DRAM pools including 2 Memory Controllers, which can cause some issues in cases when you compare against GTX 980. ROPs is especially important on memory intensive tasks such as high resolution and VRAM usage over 3.5GB which have been exclusively what this mess have been about.
     
    Last edited: Feb 3, 2015
  10. Mr.Koala

    Mr.Koala Notebook Virtuoso

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    Is there any explanation why one was disabled?
     
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