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  • Dual CPU & G400

    This is actually a reply to an earlier thread, but I kept getting errors about a lack of disk space.

    Just some notes on SMP machines. The 50 / 50 split that you see when running a single threaded application is not good, it is far better to assign the process to a single CPU to avoid cache invalidation and time wasted by context switches. Windows 2000 fixes this to some extent, threads tend to stick to one CPU wherever possible.

    Secondly Q2 on my Voodoo running under NT on a dual 400 machine was noticeable faster than Windows 98 on the same machine (where obviously only one processor was used), so even single threaded apps will benefit, especially if they spend a lot of time in system code or drivers.

    Lastly, video drivers can be written to take advantage of SMP machines. To my knowledge Matrox has never attempted this, and given their current track record with NT support I wouldn't be holding my breath. Windows 2000 may turn out to be the best gaming platform yet, so I hope Matrox re-think their strategy here.

    ATI apparently have SMP optimized drivers for the Rage 128 line, it would interesting to find out how great a difference this makes.

    Paul

  • #2
    PaulS,

    It may not necessary to be your Voodoo2 card, but the software. Have a full screen directDraw game (Diablo, as an example) running, use Alt-Tab to switch to a background application, the background application is VERY slow. That is what happened in Win95. What about NT with dual processors? You can still do whatever you want, when your character is sieged by a dozen monsters in the background, as fast as they can... oops, I forgot to pause the game.

    Maybe a single processor NT will be as good? I haven't tried...

    Nick

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    • #3
      I have tried running 2 copies of Q2 (software rendered 640 X 480) side by side on my NT machine, both windows are quite smooth - though only one has sound. Assigning both to the same processor slows things down to a crawl, much less than half the speed. Also, having only one copy running is a bit faster than 2, so the video driver is probably the bottleneck here. This might be an indication of how a well written multithreaded video driver could help a graphics intensive multithreaded app.

      I am on my 3rd SMP machine. A lot of people are pretty disappointed when they first try a SMP system, they expect everthing to be twice as fast, and it isn't - at least not in an obvious way. But there are a lot of subtle differences, I wouldn't consider going back to a single CPU system.

      I am curious about these dual Celeron systems though. The small level 2 cache defeats a lot of what SMP is trying to do - that is avoid the delays in switching threads.

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