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Is 2x XFX 7990's in (effectively quad) crossfire for gaming a good idea now?

Discussion in 'AMD / ATI' started by Inky1977, Jul 24, 2014.

  1. Inky1977

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    Hi,
    I have an Xpredator with 1x 200mm Top case fan ehaust, 2x 120mm coolmaster side case exhaust, 1x 120mm coolmaster rear exhaust and 1x 200mm front intake.
    MSI GD65 Z8Z
    i7 477k not over clocked
    XFX 750 gold Pro series PSU
    16Gb @2133Mhz (2x8Gb)
    XFX HD 7990

    I want to know, now drivers have stabilized and 99% of issues seam to be fixed with a single 7990, is it a good idea to ad another XFX HD 7990 with a 1250watt PSU into the mix for gaming?
    I've recently been offered the two and I intend to buy tomorrow!
    Any idea's or thoughts would be greatly appreciated.
    Thanks in advance.
     
  2. GhostRyder

    GhostRyder

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    Well its all relative to what you mean by that. I have run 3 - 4 GPU setups from Nvidia and AMD for quite some time now with my current setup being 3 R9 290X's and my last being a pair of HD 6990's. As far as bugs and things with CFX, normally you will see the same bugs with 2 CFX you would 3-4 and vice versa I have noticed when there are issues. So the question comes down to is it worth it to buy the extra video card in the end.

    My opinion is that 4 GPU scaling is very poor and just ends up letting people down. The scaling drops from upper 90% range in 2 card setups down to about 60 percent for the third card and 25-40 percent on the fourth.

    My advice to you, is that if you can pick one up at a good price, then yes you will be happy and get alot of performance (Though I hope you play at a higher resolution or FPS than a normal 1080p 60hz). Just be warned that its not going to be a hyper scaling adventure where you go from an average of 75FPS with 1 7990 to 150 FPS with 2 7990, it would probably be more like 75fps to 100average.
     
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  3. Law-II

    Law-II

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    Hi

    Welcome to TPU

    No not really; not sure AMD ever got their act together to support QuadfireX unless benchmarks count.

    AvP supported QuadfireX after a patch but was not an outstanding game; due to the HUD press "E" to activate this and that, there maybe a handfull of other games.

    atb

    Law-II
     
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  4. erocker

    erocker Super Moderator Staff Member

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    If you're using a 1080p monitor, the extra card would just be a waste of space and power.

    Your power supply won't be able to handle both cards.
     
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  5. Inky1977

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    Thank you for your quick and insightful thoughts. I was hoping to use my 3x 55" in eyefinity at quite a reasonable (I mean the highest possible) fps with everything (I do mean everything @Ultra/max/x16 etc) maxed @ a minimum of 1080p. Games like Crysis 3, BF4 and most of all, driving/racing sims. I was initially concerned with crash/stability issues. I am aware to a certain degree they won't run like you'd hope/expect a pair of 7990's to run. Am I right in thinking I'd be using the bottom x16 slot which will then be x8 or x4? And with what I've read, there's heat build up issues too, especially the top card? My 7990 has only ever achieved 78c on core 0 and 75c on core 2. Idle, core 0 sits @41c and core 1@38c. This is at a fairly warm room temp too this time ofyear. Will over heating be an issan? I plan on swapping the cards round after x amount if time in an attempt to share/spread the load.









    .






    eyefinity
     
  6. Law-II

    Law-II

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    Hi

    OP is going to add a 1250W PSU if getting other card; should be good to go ;)

    "1000W (or greater) power supply with four 150W 8-pin PCI Express power connectors recommended for AMD CrossFire™ technology in dual mode."
    Source here

    atb

    Law-II
     
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  7. Inky1977

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    Hi, the card will be in a deal that includes a 1250watt
     
  8. the54thvoid

    the54thvoid

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    Buying 2 dual gpu's is about as sensible as buying a Titan Z.

    Stick with crossfire and perhaps a 3rd 7970.
     
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  9. erocker

    erocker Super Moderator Staff Member

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    Missed that part. Well, you can give it a try, like I said, if you're just running a single monitor it's overkill and you may find the random issues with quadfire to make it all not worth it. Or, things could work fine for what you do.

    If it's a good deal, just do it.
     
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  10. EarthDog

    EarthDog

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    What's the point? How many monitors are you gaming on? If it is just single 1080p, no way in hell I would do that. Waste of power, too much heat and noise. Scaling is terrible compared to 1->2 cards or 2->3 even. Not worth it at all.

    If 3x 1080p... your 7990 should still be fine... perhaps grab another 7970 or 280x for tri fire is the best I have for you.
     
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  11. Inky1977

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    Please excuse any obvious spelling and grammar issues of mine. I'm using my phone and I have very limited visibility of what I'm writing. Basically, after the first line I can't see anymore of what I've written. In essence, I'm writing blind!
     
  12. GhostRyder

    GhostRyder

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    Well for eyefinity, I do that as well (Though I recently swapped to just a single 4k display) on multi-GPU's and it does work very well on 3 cards and on 4 GPU's for me (At least it did on the 6990's, but those ran out of power hence why I swapped). You should be able to max things out on most games guaranteed at 1080p with a single 7990, let alone two so I would not worry on that area because in eyefinity on 3 R9 290X's I have only come across Crysis 3 that does not keep a pretty constant 60 in eyefinity at ultra settings.

    As far as heat goes, depends on what variant of the 7990 your speaking of. All versions ran fine temp wise but you had to make sure when running 2 next to eachother to have some ventilation pushing air otherwise the top card sucked up heat. If your getting the XFX DDD edition then you have nothing to worry about, only the reference had the chance to suck in hot air when put exactly next to eachother.

    As for the motherboard, you can run it on an 8x slot but unless you are running at 16X for 2 lanes together you will lose some performance on the 7990 thats running on an 8x slot from what ive read (Though I have never personally tried it).

    If its a good deal, go for it. Otherwise I normally say 3GPU's now is the king for performance and price (Meaning your wanting to max performance without losing to much) because the 4th GPU just scales off.
     
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  13. Inky1977

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    The deal is £300 for the card and PSU. I was thinking, maybe build another system if the extra performance is minimal (overkill). In maybe 6 months I will be upgrading to 4k 55" and maybe then 2 7990's will pay dividend?
     
  14. GhostRyder

    GhostRyder

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    That is not a bad deal overall since I see the cards by themselves still running at around the 400+ dollar mark.
     
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  15. Inky1977

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  16. EarthDog

    EarthDog

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    Really, I would do the minimum amount of cards for what you need to comfortably play games at that 4K res. 3GB of vram isn't going to play nice on 4K res without some IQ sacrifices (lowering AA - which you can likely get away with... but more so on a monitor than a 55" TV due to pixel density).

    Personally, I would buy a card when you buy your 4K TV.
     
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  17. Inky1977

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    [QUOTEI think that settles it, I will skip the card. I will ask a price on just the PSU though. I think such a beast will come in handy in 6-12 months"EarthDog, post: 3140806, member: 79836"]Really, I would do the minimum amount of cards for what you need to comfortably play games at that 4K res. 3GB of vram isn't going to play nice on 4K res without some IQ sacrifices (lowering AA - which you can likely get away with... but more so on a monitor than a 55" TV due to pixel density).

    Personally, I would buy a card when you buy your 4K TV.[/QUOTE]
    Well, i
     
  18. Relayer

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    ^^^ THIS.

    If the OP's getting a good deal and he wants to mess around with quad fire, why not?
     
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  19. XFXSupport

    XFXSupport New Member

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    If its any consolation... The amount of 7990 quad fire tech support issues we get here at xfx US is so low, i cant recall the last time (if ever) i've seen one. Good luck
     
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  20. Inky1977

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    Hi again, I went ahead and bought the PSU and xfx 7990. I do have issues now I have 'quadfure'! The main issues, games from Origin do not use any of the GPUs and run @ literally zero fps. Crysis 3 (apart from a hard copy v1.0, that works a treat @130+fps 1080p with with everything on ultra and AA ETC), Bf4, titanfall etc do not. Whereas all steam games run a treat! Could this be a fluke or simply an issue with origins installers?
     
  21. Inky1977

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    They are both xfx 7990 DDD. Pretty dam good I've found.
     
  22. XFXSupport

    XFXSupport New Member

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    Hey Inky, Did you get this FPS issue resolved? id say if you already did a driver uninstall/re-install, it may be worth rein-stalling the games as well, or running the repair function. Admittedly, not my expertise.
     
  23. Inky1977

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    Hi, The games were fresh and the drivers were uninstalled then reinstalled. What repair function?
     
  24. XFXSupport

    XFXSupport New Member

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    Some games have a repair console in their settings or pre-launch. If the games were new-installs after the new drivers were installed, it wouldn't matter. Have you opened a ticket at xfxsupport.com yet? It wouldn't hurt to have a team of technicians directly working on a case for you.
     
  25. Inky1977

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    That's a good idea, I'll give that a try. Thank you.
     

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