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My first CF succesful but very poor performance

Discussion in 'AMD / ATI' started by Noci, Feb 15, 2012.

  1. Noci

    Noci New Member

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    Hi to all,

    I've recently purchased my second VTX3D HD6950 1GB and installed my first CF configuration, without to many problems.

    After my first euphoric state of mind in the clouds, I landed hard back on earth. Graphic performance was/is really bad in all GPU power hungry applications:eek:

    So back to the drawing board, where did I go wrong (presuming 'the human factor' would be the culprit here!).

    After endless testing with various driver versions and mostly 3Dmark11, the rig spontaneously shuts down under heavy load. So my first assumption was that my PSU didn't cope with it. Researching several sites, forums and especially the Corsair support section, I realized this 'A-brand' PSU is capable of running this configuration (that's why I choose it in the first place, when building my rig).
    But still all evidence pointed out that way. After some more testing and detailed inspection I discovered that the PSU fan did not work. Back to my dealer and got an identical replacement.
    After reinstatement i was full of hope, but it did not last too long. No improvement whats however:banghead:

    So again, time for research on the internet. After plenty of info filtering I found the main reason for the lack of performance: my mainboard MSI 870A-G46:cry:. The problem is the dividing of the PCI-e lanes over the two slots. The cards run @ 16x/4x instead of 8x/8x.

    So now I'll go for a new MB and my choice is the Gigabyte GA-990FXA-UD3. (I'll fight my wife over the extra costs later:slap:)

    My question to the TPU community is: will my current CPU Phenom II x4 690T be powerfull enough when the GPU's have their full bandwidth available? as this is also a well known bottleneck.
    Atm I've got it running @ 3.6GHz with some minor tweaks, with some research I must be able to get it higher clocked.

    I'm not switching to Intel, despite their better performance, so please no plea for that. Most likely I'll upgrade to a FX CPU later on when model range is extended and hopefully prices drop. Also the bank account has to be positive again:ohwell:. With the surplus parts, I'll upgrade my son's PC.
    I just want to have a well balanced configuration that will last for the next three years. (gaming is nice, but not to any costs, for me it is not a necessity of life!)

    Thanx for your replies in advance
     
  2. St.Alia-Of-The-Knife New Member

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    of course it will, i have my phenom ii at 3.9ghz and 6850 CF runs fine (except for damn skyrim)
     
  3. erocker

    erocker Super Moderator Staff Member

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    Increase the CPU/NB (IMC) frequency and turn off ULPS. AMD processors do limit CrossFire performance. Also, having a x16 + x4 configuration is very limiting.
     
  4. Dent1

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    No. It will not bottleneck. With your OC I see no reason why it would bottleneck.

    As far as your system shutting itself down, it does point to your PSU on the surface, but my feeling is your CPU OC isnt 100% stable and restarting could be due to that! Although you really need a decent PSU if you are considering CF'ing high end cards, one capable of atleast 25-30A per 12v rail or 60A+ since you are CF. The last thing you want is for the PSU to blow both GPUs.

    P.S. Take 3D mark scores with a pinch of salt, its good for A and B comparison, but ultimately if games run fine thats all that matters.
     
    Last edited: Feb 15, 2012
  5. BlackOmega

    BlackOmega

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    I run my unlocked 6950's (basically 6970's) without any issues using my x6 1090T at stock 3,2GHz. I know the scaling will increase linearly as the clock speed increases. Not sure how well a quad would handle them. I know my x3 720 didn't handle them nearly as well even at a higher clock speed (3.6).
    I bet an 8120/50 would scale even better.
     
  6. Noci

    Noci New Member

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    @ St.Alia-Of-The-Knife.

    Thanx for your quick response. But do the 6950's not use much more data traphic then the 6850's? Also at your MB your using 8x/8x PCI-e lanes.
    When I have the new MB the 6950's will have 16x/16x PCI-e lanes available.

    @ Erocker,

    Thanks also. I'll dig into it when I've purchased & installed the Gigabyte board. Sounds promising.
     
  7. Dent1

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    Which PSU brand/model you using. My feeling is the constant shutdowns is a combination of that and a unstable OC.

    The difference between 8x/8x and 16x/16x has been proven to not be a limitation. Your issue goes beyond mere bus limitation. Your hardware is unstable.
     
  8. Noci

    Noci New Member

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    Hi Dent1,

    it's in the system specs, a Corsair TX750M. Now with the new one I've no restarts anymore and all looks stable. From the old PSU the temperature controlled fan did not work.

    The PSU has got a single +12V rail, delivering 62A (740W) and according to Corsair capable of running 2 x 6950's
     
  9. Noci

    Noci New Member

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    @BlackOmega,

    I'll go for a FX-8xxx later this year.
     
    Dent1 says thanks.
  10. Dent1

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    your new PSU is plenty.

    If you want to get a FX Bulldozer fine, but it wont solve your issue. 3D Mark is a law under its own, try not to be a slave to it's scoring system!

    What games are you playing? What exactly about the performance are you unhappy with?

    It's late, 1am here. Night.
     
  11. erocker

    erocker Super Moderator Staff Member

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    Bottom line is yes. However, the bottleneck and the issues you are having seem to be two different things. Basically with the bottlenecking, your dual gpu scaling just won't be as good as with a CPU that can handle it better. A FX chip will not solve this. Check reviews.
     
  12. Noci

    Noci New Member

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    Hi Dent1,

    the 6950 in CF is because of my future wish to have an Eyefinity set-up and I wanted exactly the same card (unlockable shaders), that's why I've bought it now.

    The games played on my rig are: GTA, Crysis, FarCry2, Dirt3, Hard reset, Skyrim, BF3 and so on.
    The real problem is that playing them with a single card (which is supurb @ all settings high) is faster than with a CF setup. In CF there is so much lag that the games become unplayable.

    For 3Dmark11, I've used it only for benchmarking my rig with different tweaks to check for improvements on my own scores. I've got no urge to compeed with other people. That's where I've also discovered that it was the graphics that had a problem and not the Physics (CPU).

    This PCI-e lane 16x/4x is defenitely a bottleneck (and a good excuse to buy a new MB:cool:)
     
  13. erocker

    erocker Super Moderator Staff Member

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    Have you installed the latest Catalyst Application Profile?
     
  14. Noci

    Noci New Member

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    @ Erocker,

    Yep, CAP12.2 and running on Catalyst 12.3 beta & driver 8.95 without luck:banghead:.
    Tested at least 4 previous driver versions (with driver sweep, ATIman causes BSOD's). Just haven't tried a fresh Win7 installation yet. It is definitely some hardware problem as the cards preform perfectly in a single configuration (with or without shaders unlocked).

    I can still disable Crossfire in AMD Vision Engine control center and see what happens then. I knew in advance that setting up a balanced CF configuration would not be as easy as stated in commercials. All forums are full of recent and past issues, I just want to learn and understand and get it right.
    I see it as a hobby, I already have plenty of stress at work (reminds me I've get up in about 3 hours:eek:)

    And for the scaling, well with a FX-8xxx CPU the future is ahead and all is relative. If I was a milionaire I've probably owned a super computer. I can still remember when I was working in the aircraft and aerospace industries a rocket scientist told me that I had more computing power in my desktop (a Intel 386 DX 40MHz at that time:cool:) than the whole NASA team who put a man at the moon.
     
  15. BlackOmega

    BlackOmega

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    I think an FX CPU will be able to solve it --to an extent. While sure the scaling wont be better than any core i5/7, even the first gen's, however, since AMD's scale linearly it'll still be a whole helluva lot better than a Phenom II; simply for the reason that the FX CPUs' can attain much higher 24/7 overclocks.

    However, I have to agree, the best solution is to go with a core i5/7. Waiting for my tax returns and I'm getting either a 2600k or 2700k depending on the deal I can get. :rockout: Man the rest of my parts have been sitting in their boxes since almost Christmas. :shadedshu
     
  16. erocker

    erocker Super Moderator Staff Member

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    Best solution right now is to go withh at least a x8 + x8 PCI-E board.
     
  17. Noci

    Noci New Member

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    Also I've read more reviews that I can remember. It is also very hard to value them as there are a lot of peeps talking nonsens and my knowledge of software/hardware relations is limited.:ohwell: One thing is for sure: all items in a PC are related and every change has impact on several other things. Back at school it sounded so simple; bit and bytes.....:rolleyes:
     
  18. Dent1

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    I have to agree with the others. If you are changing motherboards you are better off opting for an i5 or i7. Sorry.

    I would only advise the FX if you were keeping your existing board or was doing encoding 24-7 but you are not. Either wait for Piledriver reviews or go Intel.
     
  19. Outback Bronze

    Outback Bronze

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    Agree. I had a mate running a 1055t x6 and he only used to run a single 6870. His 3dmark 11 score(metaphorically speaking) was about 4000. That was fine. He then went and got another 6870 and the score went to 6000. He gained about 50%. He thought hed get more when i said to him u need an i7 because their the best for dual card setups. So he did. He went and got a i7 2600k with mobo and sum ram and his score shot up to 8000. He gained roughly 100%. If your gona get a new board u might aswell spend another $200 and get the 2500k. It will do your cards justice. But if u find your happy with the performance then dont bother. Each to their own. :)
     
  20. Noci

    Noci New Member

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    Thanx to all of you for your replies, remarks and comments.

    Hardheaded as I am, I'll still jump in the deep and go for the FX990 chip set option to fully benefit the 32 PCI-e lanes in CF and future wise be able to 'upgrade' the CPU for the ability to use the 3.1 Hyper Transport @ 2,2GHz. (financially the CPU is not an option atm :(, the MB will serve as a foundation for future upgrades)

    Even despite the 'disappointing' performance levels of the FX CPU's which imo are purely relative and mainly a hype based on historic trends and the urge for more and more and more......
    I'm not out to create a rocking ultimate machine and am fully aware of more powerfully and/or suitable configuration options to choose from. With a platform of my present specs. I'll have plenty of computing power to fulfill my needs, as long as it is stable and everything works in real life situations. Benchmarking is merely a comparing tool for checking pro's/con's of my system tweaks, not to show off or to compete with anyone (I'm too old for that sh*t :D).


    I really enjoy putting a system together from scratch and working out all the problems I encounter. Forums like this with shared knowledge and experiences are more valuable then owning the fastest ass kicking system ever :rockout:.

    From your feedbacks, I'm confident for now that once I've installed my new MB, my current CPU will deal with it for a while. Hopefully it will resolve the CF performance issues (if not I can still make my son very happy with replacing his 4850 by one of my 6950's :cool:).

    In a while when I've implemented the desired MB upgrade, I'll post the result. Again, thanx to all of you :respect:
     
    Last edited: Feb 15, 2012
  21. Dent1

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    If that is the case keep your existing hardware. It's more than enough.



    But you can overclock the HyperTransport past 2.2GHz on your current board. No?


    Dont try to justify a bad purchase decision.

    A foundation to upgrade might not be the case. Looks like AMD might be abandoning AM3+ in favour of FM2 for future releases. So you might end up being "stuck" if you want something significantly faster than Bulldozer in the future. Which will mean 3 motherboard + CPU changes within 1 year. Expensive.

    Dont try to justify a bad purchase decision.
     
  22. Noci

    Noci New Member

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    This I didn't know yet, but this platform will serve me for the upcoming time, providing the CF issue is solved.
    Abandoning the AM3+ platform also can end up in FX CPU's on sale.
    Also take in consideration they still have to improve their chip manufactering with these 32nm chips, to coope with demand. Once they have a surplus, they can lower the prices and put some pressure on the Intel i5 2500K sales with doing with what AMD is (imo) good at: value for money!
    Still AMD will continue to use the BD architecture, followed by the PD architecture for their server activities, so it's hard to tell what the future brings as they are very media shy on this.
    Maybe there is some consumer desktop spin-off :confused:???
    I know the tendency is to create CPU's with integrated GPU's, but that will be for the profitable low-end up to main-stream market. The high-end segment is commercially only marginal and mainly for prestige (this is where they are way behind Intel). Creating real high-end versions will mean a tremendous investment in R&D, which considering the present world economy, is not a likely strategy. I think they'll focus R&D on multi-threading combinded with efficiency to catch up a little.
    Prestige=marketing and good marketing sells, just like any other testosteron influenced decisions ;). But it can also back-fire, as it did with with the high performance expectations hype of the Bulldozer

    My present MB & CPU will upgrade my son's rig (LGA775 Q6600 @ stock because of a factory locked BIOS, 4Gb DDR2 800 and he'll gain SATA 6GB/s, USB3 & DDR3), which I've planned anyway. So nothing's wasted atm. I still have a new Antec HC Gamer 620W PSU at the shelf for him, to fire it up.
    This will be my second (& last) MB then this year (the last one lasted 5 years) and as I said before, I'll settle for the present performance level. Maybe I had the wrong choice of words with calling it 'a foundation to upgrade' and should have called it a budget upgrade for better CF implementation.
    As you know keeping up with technology is expensive anyway:roll:, even budget systems.

    Thanx for your feedback
     
    Last edited: Feb 15, 2012
  23. claylomax

    claylomax

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    It depends on the game. My 1090t has no problem with my two GTX 480's; before this I had a x4 965 and only had problems running GTA IV.
     
  24. Noci

    Noci New Member

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    Update;

    I have my new Gigabyte GA-990FXA-UD3 rev 1.0 @ home :rockout:. Unfortunately I'm abroad for work this and upcoming week, so the rig rebuilding has to wait a little :shadedshu.

    I'll post again when I've installed it and tested the CF setup.
     
  25. Noci

    Noci New Member

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    Update:

    I've got the new mainboard installed and both cards are running @ PCI-e 2.0 x 16.

    In 3Dmark11 they now even exceed the hardware target score a little:nutkick:. For me this proves the PCI-e 2.0 16x/4x slots where indeed a bottleneck. CPU wise, I'll just wait for the Bulldozer updates and will see in time.

    So now I'll have to tweak the system to get the best out of it.

    Note:
    During the rebuild process I've also tried to unlock the shaders from my second HD 6950 as I did on my first one, but without any luck. Yes, were talking about identical cards with the same BIOS'ses and almost the same manufactering date.
    Flashing went fine, just no shaders unlocked
    :(.

    So for all out there who've heard it before but still don't believe it:
    SOME CARDS WILL AND SOME CARDS WON'T UNLOCK THE SHADERS :ohwell:(whatever you try)

    If you follow W1zzards instructions carefully and it won't succeed, don't waist more time on it. Try your luck with OC'ing.

    Thanx to everybody for their replies in the previous posts :respect:.
     

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