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Rob Ainscough

2-Way and 3-Way SLI support in P3D V2.3

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Hey All,

 

I know SLI is a "big" deal for many and it's a VERY common questions (and/or complaint) I get.  I can sympathize with some of the frustration around SLI, especially for those that have purchase multiple GPUs for this very product. 

 

First off, let me assure you that how I'm about to proceed may not be "user friendly" and is not officially supported.  We'll still need nVidia driver support ... that will not change.  

 

However I'm going to press forward with trying to get 2-way or 3-way SLI to work even if no official driver support from nVidia yet. I've seen other's report success.  My current plan of attack on a base (no add-on) 2.3 Pro Plus install:

 

1. Start with the AFR-FriendlyD3D.EXE approach first on 337.88 drivers and will most likely have to use nVidia Inspector to try various SLI settings.

 

2. Move onto 340.52 drivers and disable Tess to test that.

 

3. Use some Quadro performance drivers 340.66 that I understand will install and work with my Titans.

 

I'll use both AFR-FriendlyD3D.EXE and Prepar3D.EXE when tring 2-Way and 3-Way SLI.

 

I would appreciate any information/tips anyone has in regards to getting SLI to work with P3D V2.x. Toss me a bone!   I've posted the same request with LM.

 

631eba5606e1b5eb12a6be73c5f8087a.jpg

 

This weekends 3-way Titan project (waiting for someone to spot something).

 

Cheers, Rob.

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Ok, aside from the fact that apparently someone hasn't done the dishes, it would appear that the picture isn't quite as "Black" as it could be.....

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Looks like a fire sale. An odd ball line up to be sure. 3 different brand SSD's. ;o)  That and the lone Titan sitting beneath the pile of Titan Black.

Can't wait to see the video from this project. Just don't burn the house down! ;o)

Jazz

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An odd ball line up to be sure. 3 different brand SSD's

 

Haha, yeah ... I've consolidated to larger 1TB SSDs, these are baby ones (256GB) I plan to sell cheap.

 

I figured someone would find the Titan difference ... it's actually my old GTX SuperClock not the Black I currently have in my PC ... I couldn't find my original Black box (no pun intended) to use in the picture ... so I guess technically I have 4 Titans but only 3 that will work together ... I will be selling the GTX also (cheap, not those crazy eBay prices).

 

 

 


Wow. What kind of motherboard are you using?

 

It's a ASUS Rampage IV Black Edition LGA 2011 Intel X79 -- it supports 4-Way SLI, but from what I've read there is currently no benefit to going beyond 3-Way SLI.

 

 

 

 


This is going to be a very interesting thread - bring it on Rob - thank you

 

Thanks for putting me onto some good SLI info, Rich ... appreciate it.

 

Lucky for me our house is Solar panel supplemented.

 

Cheers, Rob.


I think what Beau is talking about here: 

 

 

You may want to clear out the device and window placement cfg items any time you rewire things....

 

are these entries in Prepar3d.cfg

 

[Main]

Location=783,386,1823,1164,\\.\DISPLAY1
LocationFullScreen=0,0,2560,1600,\\.\DISPLAY1
 
HDR needs to be turned OFF which is a bummer, but I'll experiment
 
Cheers, Rob.

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Haha, yeah ... I've consolidated to larger 1TB SSDs, these are baby ones (256GB) I plan to sell cheap.

 

Glad it helped out Rob :) should be great to see what you come up with 

Edited by n4gix
Rich, please do not quote the entire post when replying!

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Rob - These settings have been working for me. I'm not really up on SLI but after setting it up like this, I get 50/50 load distribution across the two 780's. I notice NO increase in fps but I don't really bother with fps. Mainly I noticed the sim was smoother and under heavy load ( clouds, rain, TStorms all at once) the degradation of fps didn't occur as fast as before.

 

I'm using these same settings in 2.3 but I'm using the default cfg set up by P3D with  no changes. Flew into LAX at night in the Twotter with medium cloud cover - fps capped at 20 - stayed at 20 all the way. FTX Global and Vector.

 

In NVidia Control panel - enable SLI - in manage3d - set Texture Filtering Quality to HIGH QUIALITY - that's all

in NVI - first RESET Prepar3d profile to defaults then

Texture filtering Quality - HighQuality

Antialiasing-SLIAA AA_MODE_SELECTOR_SLIAA_ENABLED

# of GPU's SLI_GPU_COUNT_TWO

SLI Rendering SLI_RENDERING_MODE_FORCE_AFR2

In P3d - fxaa off msaa 4 anisotropic 16x - 2048x2048

All other in sim settings as you like them. I have most maxed with cloud shadows on.

 

Vic

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Vic a quick question

 

you say you run capped fps at 20.

 

Is that thru NI and leave unlimited in P3d or capped at 20 in P3d.

 

Just used these settings and yes, 50% load share across my 2x780s as well. 

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Rob, bear in mind that many addons need P3D.exe to run,

If you can solve that it would be great.

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Well Rob, with your seemingly unlimited funds, I hope you find a solution to this problem. :smile:

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Rob - These settings have been working for me.

 

Thank you Vic ... I will try that out.

 

So far only been able to get 2-way working, I think my PSU maybe issue and/or CPU overclock is very sensitive to 3 GPUs under load.

 

AFRFriendly approach has some issues and for some strange reason with HDR on it's VERY dark ... going back to the standard Prepar3d.exe and the darkness goes away.  But so far I'm only testing in SLI 3D Performance mode (single monitor).

 

 

 


Rob, bear in mind that many addons need P3D.exe to run,

 

Yes, that's going to be a problem.

 

Lots of variants I can try out here, including SLI AA modes but those don't work in SLI 3D Performance mode.

 

On the plus side I'm seeing about almost double fps even with just two GPUs when using the Prepar3D.exe ... but I need to do more testing, so many variables.

 

Cheers, Rob.

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I notice NO increase in fps but I don't really bother with fps.

 

 

I think we are going to see more and more of this in the future with P3d, even with working SLI and faster single video cards. My bottleneck (and probably yours also) is now the one CPU core that pegs at 100% under load. It's not even clear to me yet how much of an improvement the soon to be introduced Haswell E processors will provide :

 

http://wccftech.com/intel-haswelle-core-i7-5960x-core-i7-5930k-core-i7-5820k-specifications-unveiled-flagship-8-core-boost-33-ghz/

 

http://wccftech.com/intel-haswell-e-processors-feature-upto-8-cores-20-mb-l3-cache-feature-ddr4-memory-support-x99-wellsburgx-pch/

 

unless LM can figure out how to balance the CPU load better among all the cores. And the Haswell E CPUs will require a new mobo and RAM. The flagship octacore Core i7-5960X will set you back $1000 US or thereabouts. At least one doesn't have to buy either a new PSU, case or SSDs, but that will be a small consolation.

 

The next tick (or is it tock, I can't remember) are the Broadwell CPUs in late 2015.

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try to enable your sli in your nvidia pilot.

then enable sli in NVI and active mode AFRFRindly, but only in NVI.

Then, look at yours titan's activities and look at your fps.

Second, do the same thing but disengage the sli in Nvidia pilot.

Tell me what you get  :mellow:

So I  found  an improvment, even it is'snt doubled ! 

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More testing, no difference with SLI so far using Prepar3D.exe.  The SLI AA modes didn't seem to make any difference to me - disappointing ... and there is no SGSS AA SLI mode.

 

AFR-Friendly does show an improvement of about 19% (about the same as what Beau was seeing 20%)  ... interestingly it also creates it's own AFR-FriendlyD3D.cfg in the same location as Prepar3d.cfg.  

 

Anyway, a few more things to try with the 337.88 before I move on to 340.52 with tess (can't imagine that will be better, but will try it).

 

It was good to see there is at least some benefit to SLI with the AFR-Friendly ... base on performance improvements for other SLI products that nVidia supports with a profile, I think if we ever do get a profile from nVidia it will probably realize at least 30% improvement minimum.

 

BUT AFR-FriendlyD3D still produced stutters regardless of frame rate or synch or triple buffer ... I need to do some time between frames analysis.

 

Cheers, Rob.

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I know SLI is a "big" deal for many and it's a VERY common questions (and/or complaint) I get.  I can sympathize with some of the frustration around SLI, especially for those that have purchase multiple GPUs for this very product. 

 

Hi Rob,

 

man you killing me how many Titns do you drive now in your rig. Damn i just bought a ´68 Mustang i cant keep up with your pace :D Im thinking of buying a second 780ti for v2.3

 

Many thanks again for your effort to keep us informend and up to date with your tests.

Edited by n4gix
Removed excessive quote!

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More testing, no difference with SLI so far using Prepar3D.exe.  The SLI AA modes didn't seem to make any difference to me - disappointing ... and there is no SGSS AA SLI mode.
 
 

Sorry to come back about this but did you put SLI_RENDERING_MODE_FORCE_AFR2 in sli rendering mode in NVI ?

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Rob, a side note...

 

How are those Vector drives?  I recently had to replace mine with a Samsung as I was getting SEVERE data loss and crashes.  I did a search online and it seems this is a common problem.  OCZ doesn't seem to wan to admit that there are issues with their Vector drives.  I tried to warranty mine as well but they told me flat out, nope...

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Rob,

 

try to start with a copy of the BIOSHOCK 2 profile as the base.  I have tried several different profiles and also with a default profile but the Bioshock profiles gives me the best results.

 

My problem is that with SLI enabled I cannot overclock my graphic cards, I always get an G3D.dll error. With the default settings everything is fine and I can push them to 99% without any problem.  Maybe that we need a more optimzed code from LM so that this could also be improved.

 

I only have 2 GTX580 but with v2.3 I always get my 40-50 FPS (no clouds) at 5760x1080.


nvidia_20140814_170952.png

 

nvidia_20140814_171144.png

 

Cheers,

Michael

 

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