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Upgrading my graphics cards

  1. Sep 27, 2012 #1
    I was thinking about upgrading my graphics cards from two HD 5870's to either two HD 7970's or two GTX 670's.

    Right now I have an 850W power supply, which probably isn't enough for those two cards.

    What PSU might you recommend for the cards I listed?

    I heard the GTX 670 and 680 are very close in performance and both are very energy-efficient. Is this true?

    OR I could just buy an HD 7990 or GTX 690.
  2. jcsd
  3. Sep 27, 2012 #2
    The newer graphics cards all require less power and an 850w psu is enough to power anything but the biggest monster rigs on the planet.
  4. Sep 27, 2012 #3
    Is there any real big performance gap between the GTX 670/7950 and the 690/7970?

    Will my Core i7 930 Nehalem cause a HUGE bottleneck crippling performance?

    For 1920x1080 two 670/7950's will be just as good as their flagship counterparts?

    The 3rd generation of DX11 cards are great at tesselation, and having 2GB of frame buffer gives a huge advantage over the 1GB cards, even at 1080p resolution. Some games require at least 2GB of frame buffer in order to run smoothly. The PC port of GTA4 is testament to this. 3GB or 4GB only comes in handy if you're using multiple monitors and/or running games at 2560x1600 resolution.

    The GTX 670 is probably the best bang for the buck as it is about 15% faster than the HD 7950. Plus the Nvidia cards offer PhysX and CUDA processing.

    Overall, how much faster is the dual CF 7950 or SLI 670 over my two HD 5870's?
  5. Sep 27, 2012 #4
    Your Nehalem will do just fine.

    Personally if I were to invest that kind of money into graphics cards I'd want at least 3gb of vram on each card and 8gb system ram. The way it works is the games will attempt to predict what you are going to do next like turn a corner and preload the next scene to prevent stuttering. The higher the resolution of the textures the more vram you need and the latest games are pushing the limits of 1gb vram @ 1080p in that respect.

    Textures are about 80% of the data so they need a lot of memory. In addition, ultra high resolution monitors are rapidly coming down in price and about to flood the market and, again, they require more vram. In fact, the radeon 7970 has the latest hardware acceleration for partially resident textures that allows it to use system ram if necessary for some games and even at 1080p such textures are outrageously large. Raw bandwidth issues are starting to replace shere number crunching capacity as the new limitation and Crytek has been insisting they need at least 8gb ram in the next generation consoles.

    Prices just came down on the AMD cards so I don't know which is the best bang-for-your-buck right now, but obviously the 670 and 7950 are the cutoff point where you start to pay through the nose for minor improvements in performance.
  6. Sep 27, 2012 #5
    So 2GB+ on my GPU will offer a noticeable improvement in performance for games even on 1080p resolution?

    Off-topic, but how much faster (clock for clock) is the X79 chipset and latest Sandy Bridge and Ivy Bridge processors over the old Nehalems? Someone told me about 15-20% which really isn't a significant improvement. The 3rd generation of DX11 cards are also very good at tesselation.

    The Nehalems are still quite capable chips, aren't they?
  7. Sep 28, 2012 #6
    Yes, more vram means higher texture resolutions with less stuttering even at 1080p.

    An improvement of 15-20% is considered good for a cpu or gpu, but the fact is cpu processors haven't made nearly as big a difference for gaming in recent years as the gpu does. Your nehalem is an extremely fast chip, sandy bridge i5 2500k overclocked is ridiculously fast for gaming, and how much faster ivy bridge is just doesn't matter. The only advantage with ivy bridge is energy savings and a few modern tweeks that don't really matter.

    The newer video cards are faster at tessellation, but it is it Nvidia's new FXAA and AMD's hardware acceleration for partially resident textures that are most notable. Since you can't have both on the same video card you'll have to decide for yourself which one you prefer. The real test for a gaming rig is whether you are satisfied or not and that's just not something I can give you advice on.
  8. Sep 28, 2012 #7
    If I upgrade my CF HD 5870's for two GTX 670's or HD 7950's, do I need to upgrade my power supply as well? I have a corsair TX850 850W PSU.

    At 1080p resolution, two 670's/7950's will be just as good as their flagship counterparts?

    Someone told me that I should go with the Nvidia GTX 670's as their are about 10% faster than the AMD cards, and offer physics processing and Nvidia CUDA. My local electronics store has the 4GB versions of the GTX 670.
  9. Sep 28, 2012 #8
    I already said an 850w psu is enough for anything but the biggest monster rigs on the planet. A simple crossfire/sli setup is nothing in comparison and Corsair is among the best available. If it already runs your two 5870s there is no doubt it is enough for the newer generation video cards.

    Which video card you should buy is always debatable. The prices change all the time and the question of how much bang-for-your-buck is always the issue. I'd suggest checking out the Steam hardware forums if you want the latest information on what's the best buy.
  10. Sep 28, 2012 #9
    Clock for clock, how much faster is the GTX 680 over the old HD 5870?
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