Intel iMac: 128mb v. 258mb Graphics

Discussion in 'Buying Tips and Advice' started by Spartacus, Mar 21, 2006.

  1. Spartacus macrumors member

    Joined:
    Nov 28, 2004
    #1
    Hey folks,

    I'm going to be purchasing a 20" iMac soon, but am unsure about how much video ram I should get with it. Does anyone know what the benefits of having 256mb of video ram over the standard 128mb are? If it matters, I plan to screen span with a 19" CRT and play a moderate amount of windows (hopefully) and mac games. How exactly will more video ram benefit my user experience? Thanks folks!
     
  2. Lord Blackadder macrumors G5

    Lord Blackadder

    Joined:
    May 7, 2004
    Location:
    Sod off
    #2
    If the word "games" enters into your thoughts, buy the very best video hardware you can get - especially considering that the iMac's video hardware is non-upgradeable. In this sitation it's a no-bainer: 256MB all the way.
     
  3. mmmcheese macrumors 6502a

    mmmcheese

    Joined:
    Feb 17, 2006
    #3
    When you span a desktop over two screens, half the video ram is allocated to each screen. The question you have to answer is, is 64MB per screen enough for your purposes (the higher resolution the screens, the more memory they need). If it is, then 128MB will be fine, if not, then go the 256MB route.
     
  4. rickvanr macrumors 68040

    rickvanr

    Joined:
    Apr 10, 2002
    Location:
    Brockville
    #4
    If you have the cash, get the 256MB model. It will last a bit longer with 256MB VRAM. Who knows, in a couple years 256MB VRAM may be a requirement for a piece of software you'd like to use, while 128MB wouldn't cut it.
     
  5. Josh396 macrumors 65816

    Josh396

    Joined:
    Oct 16, 2004
    Location:
    Peoria/Chicago, IL
    #5
    I agree. As someone else pointed out, you have to think about the Dual Screen set up. OS X splits the VRAM to each screen so you'll end up with 64 MB of VRAM for each screen. While that should be enough, if you're running one at a high resolution and doing video intensive tasks, you may want to have the 128 MB per screen. Personally I got the 256 MB upgrade because I knew it was something I couldn't upgrade later. RAM and HD can always be upgraded, but on the iMacs you're stuck with the Video card for the life of the machine so I wanted to make sure I got the best at the time.
     
  6. budugu macrumors 6502

    Joined:
    Sep 8, 2004
    Location:
    Boston, MA
    #6
    The eternal myth of RAM on a graphics chip. It is totally not possible to use 256MB ram by a card like x1600. Unless you are really using some n number (where n is a large number) of textures (complex at that). So choose the models, size of the monitor, HD and other stuff and then go with them it really does not make any huge difference as to the RAM on the graphics card. basic idea is that x1400 (w 512MB) is worse than x1600 (256mb) is worse than x1800 (with 128MB). THe RAM on the graphics card is least of your concerns here. but if it is a 50$ ugrade ... ya you might as well get it just for the peace of mind and for your ego boost!
     
  7. Lord Blackadder macrumors G5

    Lord Blackadder

    Joined:
    May 7, 2004
    Location:
    Sod off
    #7
    This is partially true, but a video card with 256MB RAM is still better than the same card with only 128. Not to mention that newer games like Doom 3 do indeed benefit from having the extra VRAM. If you are screen spanning the extra memory doesn't hurt either. Its worth the relatively modest price difference.
     
  8. Spartacus thread starter macrumors member

    Joined:
    Nov 28, 2004
    #8
    So does having 256 VRAM over 128 not make much of a difference for gaming? My original question revolved around real world benefit. I would like to play games with my iMac, so will having 256mb help in that regards? How does having more VRAM help? What does it actually do?
     
  9. BornAgainMac macrumors 603

    BornAgainMac

    Joined:
    Feb 4, 2004
    Location:
    Florida Resident
    #9
    I have seen this debate. Before it was 128 vs 64, 64 vs 32. Someday someone will ask if it is better to have 1 GB of video memory or go for the 2 GB model for $200 more. Someone will answer that unless you are doing just light gaming then you are better off going for the 2 GB upgrade.
     
  10. budugu macrumors 6502

    Joined:
    Sep 8, 2004
    Location:
    Boston, MA
    #10
    See there are lots of things before you can estimate the "actual" use of VRAM. the power of the processor, how many lanes has it got ... the bottle neck can be any where, when moving data. A large RAM simply stores complex textures (the only thing that takes up memory and needs to stay as moving them arround is expensive). yes a 256MB >= 128MB card. But by how much depends on lots of things ... as i said if it is a relatively cheap 50$ upgrade get it. otherwise you are not loosing much. For >100 bucks get a gig of system RAM that atleast helps you for sure.

    Ex. Stuff like x300, 9200 almost practically cannot use more than 64MB ... so 128 on them is just plain stupid. And on the same note 512 is equally pointless on any graphics card (yes inc 1800)
     
  11. Airforce macrumors 6502a

    Airforce

    Joined:
    Jan 12, 2006
    #11
    This depends on the type of memory the 256 uses compared to the 128. Sometimes, the higher mem is slower.

    In that case, 256 would perform worse than the 128.
     
  12. Lord Blackadder macrumors G5

    Lord Blackadder

    Joined:
    May 7, 2004
    Location:
    Sod off
    #12
    This is true, but I'm assuming the same memory speed - usually the slow RAM gets put on older cards to increase their saleability without increasing the cost too much.

    I disagree that 512MB VRAM cards are a waste - but you need a powerful computer to take full advantage. The 256MB card in my G4 is overkill, but it would aid performance in a G5 over an identical card with 1/2 the RAM. Similarly, very high end PCs with 7800GTX/7900GTX 512MB video cards do see a benefit from the extra memory at high resolutions and detail settings.

    The VRAM in the GeForce 7800GTX is very fast, and can really boost performance. By comparison, an el-cheapo GeForceMX4000 with 128MB has slow VRAM and a 5 year old GPU, so it doesn't really gain a big advantage with it's extra memory.
     

Share This Page