Prepar3D V3 and SLI

[flying_w 58]

Before I go off and make a regretful purchase, anyone experience with Prepar3D V3 and SLI?  In particular, is there any benefit in SLI for:

a) The prepar3d graphics workload in general

b) Running a 4K monitor

c) Running a 2K monitor, but with DSR processing the image at 4K?

 

I would like to go to 2x GTX970.  The one I have is currently doing a fine job, but I can find scenarios where is run out of capacity.

 

Thanks
Simon

[Slayer 190]

In my experience it will not yield a performance increase over a single GPU. Where it does help is with 4K and surround setups where a single GPU becomes overloaded. It can help minimize your framerate loss at these resolutions.  

 

At any rate in situations where the CPU is overloaded you will not see any difference at all in terms of sustainable FPS.

[Bob Scott 7,743]

Running dual water-cooled 6GB 980Ti cards here with a 55" 4K TV.  On a single card, I get (got) microstuttering in some situations. most notably in heavy weather.  Dual cards keep the GPU loads low enough to stay smooth.

 

I haven't regretted going this way, but as in most things in the world of flight simming, wringing out the last 20% of your performance issues is never cheap.

 

Regards

[flying_w 58]

In my experience it will not yield a performance increase over a single GPU. Where it does help is with 4K and surround setups where a single GPU becomes overloaded. It can help minimize your framerate loss at these resolutions.  

 

At any rate in situations where the CPU is overloaded you will not see any difference at all in terms of sustainable FPS.

 

I agree about the CPU.  However as I run with unlocked frames and vsync to a 30Hz screen, the CPU is often well under 100% on the main core. Indeed this gives me scenario and scenery tuning options to get more (or less if it does bottleneck) as the demand is not hidden in the way it is for simulator locked frame rates.

 

If I have read correctly, P3D V2 was optimised for SLI (by Nvidia?).  Is the same true for V3, or perhaps way too soon?

 

Thanks

Simon

[vgbaron 3,714]

Simon - I run twin 970's and have the same experience as Bob (w6kd) posted above although my system doesn't out as much a load as his. Both LM and Nvidia are working to improve the SLI performance.

 

I am very happy with SLI as it stands but there's always room for improvement in simming.

 

 

Vic

[Slayer 190]

I was working on my friends PC last night and he has an Alienware with 2 970's in SLI, did a few tests @ FSDT KLAX((P3DV3)).  It ran at about 25 FPS unlocked with the PMDG 737 - but he had added 2 additional screens.

 

With SLI off and the other 2 screens removed it runs in the range of 18-25 FPS. I believe his CPU was an non OC 4790.

 

Take from it what you will.

[tutmeister 712]

I5 at 4.7 and 2 970s in sli on a 4K screen. I run ftx global, lc, vector and all the usual add ons (ezdok, asn, precipitfx, Rex) plus airports and can turn everything up so it ooms in minutes. Generally I back things off so I can fly without worrying and get 30 fps with the pmdg ng.

As soon as I undock a screen it drops to 12-15 fps which is causing real problems for airliner flying. Asked on the lm forums but no reply yet.

If you don't undock anything then sli is good as you don't take the hit when you turn everything up.

It's just a shame we can't have it all just yet. We have the power to run all these add ons but can't due to ooms.

 

Chris

[flying_w 58]

Thanks all for contributing, sounds like SLI and 4K are worthy investments.  I won't expect FPS miracles!

 

Simon

[RedSpinnaker 35]

Running dual water-cooled 6GB 980Ti cards here with a 55" 4K TV.  On a single card, I get (got) microstuttering in some situations. most notably in heavy weather.  Dual cards keep the GPU loads low enough to stay smooth.

 

I haven't regretted going this way, but as in most things in the world of flight simming, wringing out the last 20% of your performance issues is never cheap.

 

 

Recently moved to a 50" 4K display (don't think I'll ever go back). Started experiencing some microstuttering (running single 6GB 980Ti). Do you think going with a single TITAN Z would result in similar performance as twin 980Ti's (SLI)? The reason for the question is my current rig is an mITX build. So, if I have to go the SLI route, it's a whole new build (and I'll likely jump down the dual loop liquid cooling rabbit hole again).

 

So, spending $$ either way. Just curious if the TITAN Z would be worth it, or I should just pull the trigger for a new build.

[Michael Moe 496]

I am getting hang off using my 2 GTX970SC. from EVGA anytime i fly the Dash8 or GA. It gives my room for shadows but as i am still only using 1920x1200 it is only in real bad weather i see them peak from time to time at 75%.So a nice compromise here and glad i bought them now.

 

Michael Moe

[Bob Scott 7,743]

So, spending $$ either way. Just curious if the TITAN Z would be worth it, or I should just pull the trigger for a new build.

 

I'm not a fan of the dual-GPU boards based on experiences with a few earlier generations, but that said, I don't know enough about the Titan-Z specifically to know.  I know that I can disable SLI in my setup to run FSX on a single GPU and it works well...not sure about how that'd work in the dual-GPU board.

 

Regards

[Gordon Hutchison 76]

I'm running a 4K monitor with GTX 980Ti SLI.

 

My experience is that it doesn't make much difference to maximum FPS, but it will help maintain steady FPS in situations like heavy cloud and it will also make using SGSS AA less of an FPS killer.

[RedSpinnaker 35]

I'm not a fan of the dual-GPU boards based on experiences with a few earlier generations, but that said, I don't know enough about the Titan-Z specifically to know.  I know that I can disable SLI in my setup to run FSX on a single GPU and it works well...not sure about how that'd work in the dual-GPU board.

 

I've decided to go the second 980Ti route and run in SLI (along with the costs of a new mobo and case) as it'll allow for more flexibility long term.

 

You mention FSX.. however earlier you mentioned the second 980Ti resolved your microstuttering in heavy wx with your 4K display. Was that P3D?

 

Thanks!

[Bob Scott 7,743]

You mention FSX.. however earlier you mentioned the second 980Ti resolved your microstuttering in heavy wx with your 4K display. Was that P3D?

 

 

Yes, P3D.  FSX is a DX9 application that can't make use of SLI, and generally multiple GPUs and FSX are problematic.  P3DV3, on the other hand, puts both GPUs to beneficial use quite well.  So when I run FSX, I take the GPUs out of SLI in the NCP and let one of them idle.

 

Regards

[RedSpinnaker 35]

Gotcha... That's what I thought you were saying..

 

Thanks!