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I have the opportunity to purchase a second 980 (EVGA 980 SC) for my system and I was wondering if SLI improves the performance of P3D. I am not looking for high frames but rather want reduce choppiness and blurry textures and improve the smoothness of my flying, especially when in heavy clouds. I believe my supporting hardware is reasonable (4790K @ 4.8GHz, 16GB of 2400MHz RAM, and Windows 7 with P3D on a stand-along SSD). I should also mention that my monitor is 1900X1200 so not very demanding resolution-wise.

 

I'm curious as to what I can expect in performance as well as any potential problems I may have getting SLI to work with P3D. 

 

I know this is a hardware question but I posted in here as my question is specific to P3D.

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Vic

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I'm running P3Dv2.5 with GTX 970's in SLI, 3840 x 2160 @ 60hz. The second card is definitely an improvement in smoothness.

 

I don't change any particular settings, I just enable SLI in NVIDIA Control Panel.

 

Cheers

Steve

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I don't change any particular settings, I just enable SLI in NVIDIA Control Panel.

 

Steve - are you sure you are using SLI within P3D though? Enable the SLI indicator in the Nvidia control panel (Tools) and run P3D. If you see a green bar along the left side of the screen that fluctuates vertically as you move, SLI is enabled. If you don't - P3D is *NOT* in SLI mode.

 

Vic

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I see no improvement in sli unfortunately. Using 2 gtx970 to drive my 4k screen. I'm actually seeing a few fps less in prepar3d. To run in sli I'm using either the afr friendly exe method or ni to enable. I know sli is running as I can get the sli overlay displaying on the left. I turned everything up to max in orbx uk and when I'm sat in the ngx at Manchester I get about 20fps. With sli it is a few frames less and hardly any green bar shows on the overlay.

Only had sli for a couple of days and haven't had chance to play around more and see if I can get more. By contrast I get full usage and 75fps with ultra settings in 4k when running Elite dangerous.

It is a shame but I guess we will just have to wait a bit longer for proper sli in prepar3d.

Chris

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Steve - are you sure you are using SLI within P3D though? Enable the SLI indicator in the Nvidia control panel (Tools) and run P3D. If you see a green bar along the left side of the screen that fluctuates vertically as you move, SLI is enabled. If you don't - P3D is *NOT* in SLI mode.

 

Vic

When I enable the SLI indicator I do see the green bar in P3D.  I also see that I indeed did change a couple SLI settings in NCP and NI. 

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ok - that makes sense. I've been running my two 97's for several months and I o notice a difference from single card.

 

Vic

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" If you see a green bar along the left side of the screen that fluctuates vertically as you move, SLI is enabled. If you don't - P3D is *NOT* in SLI mode."

 

No green bar at 3D2.5 screen.

Will you please give me step by step direction how to enable the SLI'

Thanks

 

http://imageshack.com/a/img540/4350/Jm0jg1.jpg

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Is it that complicated to write this damend SLI-Profil?

Maybe someone could setup a Kickstarter Project and collect some money for a talented programer to do the Job.

Just thinking loud...

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Excellent idea, I hope some one takes the lead for this project.

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I've ordered the second 980 and should have it by the end of the week. Good or bad, I'll post my experiences here. 

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Vic,

 

Will you please check my post #9,

Thx :yahoo:

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Vic,

 

Will you please check my post #9,

Thx :yahoo:

This may help -

 

http://www.flightsim.com/vbfs/showthread.php?286443-Prepar3D-settings&p=1900022#post1900022

 

First - go into Nvidia control panel and enable SLI in "Configure SLI...."

 

Then in Program settings - Manage 3D - SLI Rendering mode - select Nvidia recommended

 

Then open NVidia Inspector - select the P3D profile - click the icon to reset to default -

 

The AA settings I show are high - I have since dropped them to 8x from 32 BUT this is configurable to YOUR liking - some will produce artifacts and shimmers - depends on the system - start with my settings and adjust.

 

the IMPORTANT NVI settings are the SLI -

 

Antialiasing SLI AA - AA_MODE_SELECTOR_SLIAA_ENABLED

 

and

Number of GPU's - SLI_GPU_COUNT_TWO

 

I've found that if this is NOT set to two - it doesn't work - on my system.

 

AS I said earlier - enable the SLI indicator - if it's showing and moving when P3D is running - it's working.

 

I did NOT see any FPS increase - but I lock at 20 - what I DID see was that it took longer for my system to get to 100%GPU usage in extreme situations than before. When that happens, the FPS can drop as the CPU gets slammed more - so in SLI that "break" happens less frequently, if at all. Again, I'm talking about a high res a/c with really bad weather and rain in complex scenery. Normal situations just cruise along smoothly.

 

Whether or not the gain is worth the cost of the card is up to the individual.

 

HTH,

 

Vic

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Right, so second 980 was installed and tested with multiple games and bench-marking applications ( Unigine Valley and 3D Mark Firestrike) to confirm the SLI is correctly configured and is stable.

 

Loaded up P3D and found a strange problem. The GPU load is pretty even across both cards but if I switch aircraft, only one card is loaded. 

 

I should mention that the SLI indicator shows activity when panning or changing views in the first image but freezes in that position when I changed to the Duke. This happens with any aircraft I switch to btw.

 

See below:

 

Initial Scenario Load:

 

P3D-SLI-Initial_Load_zps1k2vwdsa.png

 

 

Change Aircraft:

 

P3D-SLI-Switch_Aircraft_zpsq0tfdfdp.png

 

Any ideas would be greatly appreciated.

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Not being a smartass, but have you tried a different monitoring program? MSI Afterburner or EVGA PrecisionX and see if the results are the same?

 

Do you have the GPU count set to TWO in NVidia inspector?

 

Vic

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Not being a smartass, but have you tried a different monitoring program? MSI Afterburner or EVGA PrecisionX and see if the results are the same?

 

Do you have the GPU count set to TWO in NVidia inspector?

 

Vic

 

Yes, Precision X and Yes, set to SLI_GPU_COUNT_TWO

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Right, so second 980 was installed and tested with multiple games and bench-marking applications ( Unigine Valley and 3D Mark Firestrike) to confirm the SLI is correctly configured and is stable.

 

Ignoring the switching aircraft problem for the moment can you see any improvement in P3D with SLI verses one card?

 

gb.

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Ignoring the switching aircraft problem for the moment can you see any improvement in P3D with SLI verses one card?

 

gb.

 

After figuring out how to load P3D and have both cards active, my total increase in FPS was exactly....zero.

 

What I did get is no real loss of FPS and the smoothness and performance remained pretty stable in conditions with heavy clouds and scenery texture loads would have a negative effect on my single card.

 

At this stage in my little journey, this is not a solution I would recommend unless you're going SLI for other reasons, which I am.

 

I did notice that overclocking the cards did help a little with FPS but again, nothing to write home about.

 

I am also not using the latest drivers (I am at 347.88) as I don't want to lose my runway lights so I could be losing out there.

 

Its interesting to note that opening any menu option in P3D also breaks SLI and reverts to using the primary card. I figure I must be missing a setting somewhere but I'll be damned if I can find it or figure out what causes this.

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Vic,

 

 

Thanks for your info. SLI finally enabled but I didn't see any performance changes. I came to conclusion, we will not get any joy from P3D until they change the code to 64 bit from 32.

 

I remember once I was speaking an expert regarding PC software. He told me don't invest any more money to P3D, their code base from FSX is old, will not match 64Bit, therefore you will loose half of your performance and cannot be gain until P3D recoded 64bit.  :Confused:

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How can I close  SLI green bar from screen during flight?

 

Thanks

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