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DFI owners: Performance hit running GFX card in lower slot? Lets clear this one up

Discussion in 'Motherboards' started by sniper007, 18 Jan 2006.

  1. sniper007

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    Joined: 18 Jan 2005

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    For those that are not quite aware, with DFI Nforce4 mobos such as the Ultra-D, SLI-D, SLI-DR, they have 2 x PCI-e slots. Lets be clear that for this discussion we ARE NOT TALKING ABOUT SLI.
    Such owners of these MOBOs, have the ability to run a single GFX card in the normal x16 PCI-e slot, of they can run it in the lower slot (PCIe slot 4) which by default will have a bandwidth PCI-e lane of x2.
    Now, one can set the jumpers on the MOBO for each of these slots from "normal" to "sli" (regardless of if you plan to or even can run SLi) so that the normal x16 higher slot goes from x16 to 8x, and the lower slot goes from x2 to x8 as well.
    This is really for the use of SLi. However, as explained above, a lot of people use this method to set the lower slot at x8 so that they can run their card in this slot with no performance hit from x16, in order to free up the chipset area for passive sinks.

    Why would there not be a performance hit I hear some of you possibly ask? Well, the idea is, that a lot of todays generation of GFX cards as they currently stand, are not powerful enough to warrant the full use of the PCI-e x16 bandwidth and hence would not see a hit running at 8x. In fact, Toms Hardware did a test about a year ago, and they found that cards then only really required a PCI-e slot at 4x.

    I would like to hear of others findings to see if you experienced a performance hit. I have read on other forums misleading info. Some say there is NO performance hit. Some say there is. Some say that it is very very minimal at like 1% max.

    Personally, I had to test this for myself. On my system currently I set it to a conservative clock (in that the CPU can do much more at 11x) of:
    10x285 HTT 2.85ghz Opteron with ram @ 285mhz @ 1:1

    The GFX card is an x800 GTO2 unlocked to 16pipes clocked to 520/600.

    I get:

    EDIT!!!

    See my post further down as I have rebenched everything now PROPERLY and the results are all below.
     
    Last edited: 20 Jan 2006
  2. Arcane

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    Have you tried any real world tests? Synthetic benchmarks can be misleading, I've also heard there's minimal difference in games, though admittedly have never needed to test it as I run SLI.
     
  3. easyrider

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    I was wondering about this too.I have just bought the dfi expert but I was tempted to buy the Asus A8N32-SLi Deluxe nForce4 SLi X16

    Is this 2 x 16 pci-e nesscessary?
     
  4. sniper007

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    Potentially yes for the future. Why would you worry about this with the DFI expert though? One of the main revisions worth buying the board for is that the chipset has more space for different cooling solutions since the two main pci-e slots have double spacing.
     
  5. easyrider

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    If moving from another Nforce 4 mobo do I need to reinstall windows when installing the new mobo?

    Or will the nvidia drivers be ok.I wont be using the onboard sound
     
  6. Jimbo Mahoney

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    In this situation (testing throughput of the PCI-E bus), I completely disagree.

    3DMark will be excellent for testing the upper and lower slots, especially since you are using '01, '03 and '05.

    '01 is largely CPU-limited, '03 is a blend and '05 is massively GPU-limited. The reason, I suspect, for '03 showing the biggest hit is because it is GPU-limited enough to be bandwidth-limited, but not GPU-limited enough for your GPU to struggle to produce the data (unlike '05 where the actually GPU processing is the limiting factor).

    Also, if you run any 3DMark a few times, you will find the score vary VERY little, like 1%.

    Thanks for doing these tests - very interesting. I hadn't realised the lower slot was THAT much of a sloth.
     
  7. sniper007

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    Ok update...

    Ive decided to void all of my above tests because something funny is going on with my benching. The scores I used to be able to get in my x16 slot I now cant, and Im trying to work out what it is that is affecting it. Now when I run 3dmark 2001 in the pci-e slot 4 @ x2 its scoring MORE than @ 16x slot. Something odd is going on and tonight im going to blitz through a load of benching to test this properly once and for all.

    I shall test the 3dmarks @ x2 x8 and x16 and will make sure I lock the system down to constant BIOS settings for no variations. I will even take averages for arguments sake. What a fun evening I will have.
     
  8. PinkFloyd

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    Joined: 21 Sep 2005

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    Location: Bradley Stoke, Bristol

    I'm going to have to try some of this out myself. Since fitting a Zalmon Passive chipset cooler I moved my gf card down to the lower slot, (I couldnt be bothered with cutting off pins and the like)
    I noticed about 200 point decrease in speed from going to the bottom slot and didn't change the jumpers at all.

    Are you sure the drivers arent acting differently on the different slots, because when I changed slots I had to completely reinstall the drivers
     
  9. sniper007

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    Yeah Im thinking it could be driver related this. This is getting frustrating now. Random things are happening to my PC now. 3dmark2001 just locked up for first time ever. I think this must be driver related.
     
  10. sniper007

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    OK update. Started from scratch and this time everytime I changed jumper settings I blitzed all drivers and reinstalled them using the latest Omega 6.1 Catalyst drivers. Driver cleaner pro was used to get rid of any old driver traces and everything was defnitely kept constant with all fans @ 100%. Also got rid of TRIXX and ATI Tool and had just the Omega 6.1 Catalyst package on there.

    All benchmarks were ran three times and an average was taken (mean value).

    PCI-e Normal x16slot

    3dmark 2001: 27684
    3dmark 2003: 11838
    3dmark 2005: 5423

    PCI-e Slot 4 (lower slot) x8

    3dmark 2001: 27656 = (- 0.101%)
    3dmark 2003: 11791 = (- 0.397%)
    3dmark 2005: 5417 = (- 0.111%)

    PCI-e Slot 4 (lower slot) x2

    3dmark 2001: 25350 = (- 8.431%)
    3dmark 2003: 10739 = (- 9.283%)
    3dmark 2005: 5066 = (- 6.583%)


    So it would appear that my original benches were going wrong somewhere. I think maybe the slot was still running at 2x. Anyway...these benches clearly show that people are right when they say that the difference is minimal. I mean I wouldnt have said 5-10% would have been noticeable in any game, let alone 0.3 % !!!

    Bare in mind, this was with the GFX card clocked at stock settings. Had the gfx card been overclocked, I dont know if the difference would have been greater slightly. But theoretically, it should be pretty much the same difference as both slots would still be running the same clocked card. I guess I could test this to be sure, but frankly, Im happy already with using my lower slot, until cards really need x16. Saved me chopping up my passive zalman anyway.


    If anyone else could test to be sure that would be great.
     
    Last edited: 20 Jan 2006
  11. Jimbo Mahoney

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    Ahhhh.

    Good work fella!

    I think a lot of people running in the lower slot and complaining were leaving the jumpers at default, which is 2x, right?
     
  12. sniper007

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    Correct.

    TBH, if 8x was a bottleneck then SLi would surely have suffered which would have been silly, since the whole point is to up performance. Cards of the future such as the next gen ones, may however require these new upcoming boards with 2 x PCI-e slots @ 16x. But, I have seen results somewhere where a guy used even a 7800gt and actually claimed he GAINED 3dmark points in the lower slot on some benches.

    So the moral seems to be, use the lower slot if it suits you, but make sure you set the jumpers correctly and you might have to / want to, reinstall drivers from scratch to make sure there are no issues.
     
  13. Arcane

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    Nice sniper007! :)
     
  14. Chaos_Darklight

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    Joined: 9 Jan 2006

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    Location: Chester, Cheshire

    SLI-DR Expert

    I'm having a problem here... I just got this board yesterday from overclockers, set the thing up an got to the part on where i was to install the second 7800 GT i have for the SLI Setup...

    Now when i installed the card, Bridge and power cables and booted up I went to the desplay pannal and the it told me in the section where you normally select if u want SLI Enabled or Disabeled it told me i have to remove any none SLI Compliant cards before i can enable SLI...

    So i remove both cards....but the second card in to slot one and boot up...that card works, just has the first card did when i booted that up on its own...then i thought it could be the second SLI slot, so i removed the card from slot one and placed it in slot two...the graphics card worked, so both cards are running fine, they were running fine in my last system with the Asus A8n SLI Premium board i had.

    Any ideas people, i've tired both cards on their own, and they work...the control panel says when i have just the one card, to insert a SLI compatable card and bridge the connection to enable SLI, when i do so, the message about removing the card as mentioned above appears.

    "HELP"

    Is there a jumper on this to enable set up SLI that i have missed???

    The manual doesn't point one out, an i cant see one...how do you set it SLI up then.
     
  15. PinkFloyd

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    Hmmm I havent changed the jumpers at all.
    Was going to do it last night, but couldnt reach to swap them over without taking the gfx card out. But will give it a go tonight.


    I'm going to have to use the top slot soon, I am upgrading to an X1800XT (maybe 1900 we'll see) so I need space for the huge cooler on it, so that counts the bottom slot out if I want to use any PCI cards..... Its tight enough with my current gfx card.
    I'm not looking forward to butchering the cooler..... and they are a pain in the ass because of the pushpins. Had to resort to cutting them off last time I had to remove some..... (any hints here?)
     
  16. sniper007

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    Some geezer on here has done a nice job butchering it. But I emailed him and he didnt reply. About half way (?) through the official DFI Ultra/SLI-SLI-DR thread theres a puc of it.
     
  17. PinkFloyd

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    Joined: 21 Sep 2005

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    Yeh thats What I'l be doing soonish ;)
    should be funny :p

    Did my own tests on this. Overclocked my rig, (you'll see in the screenshots how far)
    I overcloked to a quik level, couldnt be bothered to push further, ran the gfx card as fast as I can and ran 3dmark03. (thinking that its less likely to be held back by raw gpu power than 05)

    The first screen is before, with the 2x (this is what mine has always been on)
    below it is with the jumpers set to have it running at 8x.

    http://img.photobucket.com/albums/v607/The_Head/11688-3d03-before.jpg
    http://img.photobucket.com/albums/v607/The_Head/12117-3d03-after.jpg

    I got a small performance increase, but I doubt it will be noticable in games, I'l report back if it is.

    Its just strange that the max you can have the secong slot running is 8x, yet it claims to have two 16x PCIe slots - or 2x 8x if you are running SLI.....