Test for someone with m295x, need to compare my m290x

Discussion in 'iMac' started by rick987611, Oct 22, 2014.

  1. rick987611, Oct 22, 2014
    Last edited: Oct 22, 2014

    rick987611 macrumors member

    Oct 28, 2008
    So I picked up a base model iMac Retina. Everything was silky smooth until I hooked my other 1440p monitor up. Now mission control is pretty laggy. Remove the extra 1440p and everything is perfect again.

    I would like to see someone test it out on the upgraded video card. I use mission control a bunch so I would be willing to return the computer and order an upgraded one if it is going to be laggy.

    uploaded a video of it with and without the extra monitor plugged in:


    Wasn't as laggy as it sometimes gets in this video, but it shows what I mean.

    Edit: Another way to test if you have an m295x, but no 1440p monitor, is to open up a bunch of windows and crank the scaling all the way to the top. If I do that on the 290x without the external display hooked up it can get laggy as well.
  2. WilliamG macrumors G3

    Mar 29, 2008
    I can't imagine any upgrade would fix that kind of lag. That looks more to be like a software issue (nothing you can fix, but hopefully something Apple can fix).
  3. jji7skyline macrumors 6502


    Aug 10, 2011
    A 5K monitor with a 4K monitor is a LOT of pixels. Over 18 million. In comparison a Full HD 1080p monitor only has 2 million.

    If you're serious about using both monitors, it may pay off to get the upgraded GPU.
  4. rick987611 thread starter macrumors member

    Oct 28, 2008
    I've always had it on my rMBP, but I just chalked it up to the integrated GPU not being strong enough. I figured the discrete GPU would be able to handle it fine regardless of which one I decided on.


    That is why I made this post, to see if the GPU is the bottle neck or not. I am just not sure because everything else is silky smooth. Also, I'm not running another 4k monitor, just a 1440p monitor.
  5. jji7skyline macrumors 6502


    Aug 10, 2011
    That's crazy :eek:
  6. Georgio macrumors 6502


    Apr 30, 2008
    Essex, UK
    Anyone who would need to hook up an extra screen to the RMac would definately need the 295 GPU as the 290 can barely cover the 5k screen let alone another screen.

    People should realise that the minimum GPU for the 5k screen isn't the 290 GPU, well not unless all you're going to do is some browsing and mail...:rolleyes:
  7. macmee Suspended


    Dec 13, 2008
    well I got the upgraded gfx and plan on hooking up another 4k monitor

  8. acantril macrumors member

    Apr 2, 2011
    your issue is the scaling... anything thats not native is using software and takes a large performance hit. Try gaming on a rMBP anything thats not the pixel double native res cries.
  9. WilliamG macrumors G3

    Mar 29, 2008
    Funny! I'd be surprised if the 295 makes that lag any smoother, but I'll wait for someone else to test that with the upgraded iMac.
  10. princered macrumors member


    Jul 31, 2014
    I too am waiting before making that purchase. I actually don't plan on buying the riMac for a few more months. Yet I'm glued to MacRumors trying to see how well these graphic cards hold up.
  11. hyune83 macrumors member

    Sep 19, 2008
    Have you tried anything video intensive by chance? Was wondering as I'm deciding between the 290x vs 295x
  12. rick987611 thread starter macrumors member

    Oct 28, 2008
    I'm using the default scaling and running the extra monitor at native. Nothing fancy.
  13. theSeb macrumors 604


    Aug 10, 2010
    Poole, England
    This could be Yosemite causing the problem (a software problem). Plenty of people are reporting similar issues over in the Yosemite section of this site with different hardware. Is WindowServer taking up lots of CPU in Activity Monitor when the second monitor is connected?
  14. steve23094 macrumors 68020


    Apr 23, 2013
    So you normally game at 2880*1800, or an even ration like 1440*800?
  15. kendrickhphoto macrumors member

    Jan 20, 2011
    My order has been in Processing Items for almost a week now and it says the delivery estimate is 10/28-10/30.

    Once I do get it, I will be hooking up my 27" Cinema display and Thunderbolt display to it. I can do tests with either of those by themselves or together for you.

    I got the i7 and the m295x so if no one else helps you before then let me know what exactly you'd like me to do.
  16. CausticPuppy macrumors 65816

    May 1, 2012
    It's most likely due to video memory and not GPU performance.

    18 million pixels is roughly half a gigabyte just for the frame buffer, assuming you're running in "best for retina" resolution. Even more if you're using a scaled resolution.

    I'm not an expert in this kind of thing, but it seems reasonable to assume that it's double-buffered for smooth animations, so that's 1GB total for onscreen and offscreen buffers. Then add in all the texture memory required for the GPU-accelerated ui rendering; the desktop backgrounds themselves are a texture, and will use up the same amount of memory as a frame buffer just for the backgrounds, and then add the textures for all the windows and it's hitting the 2GB limit very quickly.

    The stuttering is due to textures being swapped in/out of system memory.

    That's why 4GB is a BTO option. If you plan on running a secondary 4K display, you need the 4GB if you want smooth UI animation. You should be able to run a secondary 1440p panel OK, though it might still be cutting it close.
  17. rick987611 thread starter macrumors member

    Oct 28, 2008
    This is kind of what I'm thinking at this point too. Just wanted someone with the upgraded graphics to try it out and see if it really matters. If it does I will be swapping out units for sure.
  18. dlewis23 macrumors 6502a

    Oct 23, 2007
    4GB should have been the standard. I purchased the base and I have the same UI lag with mission control and in other areas of the UI with no external monitor connected.

    I love the display and the rest of the computer so far except for the UI lag. I'm thinking about ordering with the m295 if it doesn't happen there.
  19. rick987611 thread starter macrumors member

    Oct 28, 2008
    I agree. I think I'm going to go return and order with the upgrade. That UI lag is going to drive me nuts if I think I could have fixed it for a measly $200.
  20. CausticPuppy macrumors 65816

    May 1, 2012
    Not necessarily, 2GB would be plenty for the typical user who doesn't need a second display. But they should say on the CTO page that 4GB is recommended if you use external monitors (especially 4K).
  21. iSee macrumors 68040


    Oct 25, 2004
    Wait a sec: It's more like 15 million pixels (well, 14,745,600). A 32-bit frame buffer would be less than 60 MB... 2 GB is enough RAM for 36 full screen 32-bit buffers.

    Either your math is way off, or mine is. (Hope it's not me!)
  22. dlewis23 macrumors 6502a

    Oct 23, 2007
    I have the base config and no second display and there is still UI lag and sluggishness. There is a lot of it with mission control and even opening a new tab in Safari the animation is extremely sluggish.

    it shouldn't be like that with either GPU option but pushing that many pixels to me it seems the m290x is not enough of a GPU for even the OS X UI.
  23. ElectronGuru macrumors 65816

    Sep 5, 2013
    Oregon, USA
    Is there an app that shows vram utilization in real time?
  24. Roman2K~ macrumors 6502a

    Mar 11, 2011
    There's iStat Menus and atMonitor (abandoned).
  25. CausticPuppy macrumors 65816

    May 1, 2012
    I messed with one in the Apple Store and noticed the same thing. Base model running in best-for-retina resolution. Seemed to choke more when the pro apps were open. It was pretty jerky scrolling around an image in Aperture.

    Most users would be fine but photo/video folks should definitely spring for the GPU upgrade, though who knows how well that one performs.

    Also it could be a matter of additional software optimization like it was for the retina macbook pros-- those improved over time with software updates.

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