pcie 3.0 x8 vs x16 1080ti sli

corndog1836

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The title says it all.. I believe that 2x 1080ti's in SLI finally saturate the bandwidth at pcie 3.0. 8x + 8x for sli...how much is the question....doea anybody have data...
 
Solution
1. There is always an "overhead" associated with SLI, some of that due to the drop to x8 x8. This small impact is for the most part offset and then some by the additional scaling as is clear;y shown in the provided link.

2. On the flip side however, w/ OP at 1440p, SLI isn't looking too good right now. TPUs scaling across their 16+ game test suite showed just 18% at 1080p and 33% at 1440p. Only 2160p showed an increase that just passed 50%. So while there are significant gains to be had at 4k, ... more at 4k 144 hz w/ next months monitors as they enable the user to use ULMB, it's hard to justify the cost investment for 33%.


Why the sudden drop off in SLI performance after stellar performance with 6xx thru 9xx series ? Could...

corndog1836

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I am going to add a custom water cooled system to my rig in sig ,with two 1080ti Asus Poseidons or two MSI Seahawk X EK blocks.
I read this article and got a little scared of doing this.
https://www.pugetsystems.com/labs/articles/Titan-X-Performance-PCI-E-3-0-x8-vs-x16-851/
 

corndog1836

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I am in 1440p 144mhz.... z97 asus maximus vii formula. 4.8ghz 4790k . I want 2x 1080ti in sli to replace my 780ti sli setup.(every couple years I treat myself) I am doing my first custom water loop and expect to get MSI seahawk EK X 1080tis but am worried about bandwidth , I can run them at pcie 8x +8x . I know I am nuts but this is my only hobby!!!!! what do you think ... will there be a noticeable bandwidth bottleneck. opinions????
 

maxalge

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look around for titan XP benchmarks in sli


they are basically the same as a 1080 ti



from me just looking around a bit seems performance loss in 8x/8x mobos on titan xp sli results in 10 - 30 % loss when compared to 16x/16x solutions
 

corndog1836

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yea that's what I was afraid of... don't know if its worth it to get 2 1080ti"s..... I still is a good bit of improvement to buy SLI 1080ti's for RISE OF THE TOMB RAIDER and MASS EFEECT ANDROMEDA, and hopefully PREY.. I would be somewhat bottlenecked by PCIE BANDWITH THOUGH.... I want to play these games at 100+ FPS at 1440p with all EYE CANDY (((((ULTRA)))) and will probably replay the Metro Redux series and some Fallout 4 DLCs .... all of these games seem to do Very well with SLI with less bandwidth loss. this video shows that is different with each game. WHAT TO DO????

https://youtu.be/HchSu5peIoc

2-3 years from now I will upgrade cpu and mobo anyways!!!!!!
 

corndog1836

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https://www.pugetsystems.com/labs/articles/Titan-X-Performance-PCI-E-3-0-x8-vs-x16-851/
THIS LOOKS PROMISSING(I am glad I read it over a second time)... the results are better as you stress the cards with ultra settings or higher resolution..

MAYBE 1080TI'S IN SLI ISNT SO BAD FOR ME AFTER ALL.....more mature drivers for 1080ti may help allitlle as well

 
1. There is always an "overhead" associated with SLI, some of that due to the drop to x8 x8. This small impact is for the most part offset and then some by the additional scaling as is clear;y shown in the provided link.

2. On the flip side however, w/ OP at 1440p, SLI isn't looking too good right now. TPUs scaling across their 16+ game test suite showed just 18% at 1080p and 33% at 1440p. Only 2160p showed an increase that just passed 50%. So while there are significant gains to be had at 4k, ... more at 4k 144 hz w/ next months monitors as they enable the user to use ULMB, it's hard to justify the cost investment for 33%.


Why the sudden drop off in SLI performance after stellar performance with 6xx thru 9xx series ? Could be many things.

a) Generation to generation, we saw a 50% improvement in GFX card performance this time.... we haven't really seen a tenth of that with RAM or CPUs since Sandy Bridge in 2011.

b) Driver developers are saddled with tweaking drivers for new APIs (DX12, Vulcan), new games, and SLI, which is now only supported on 3 cards, reduces the3 % of cards out there with option to use the technology.

c) Improving SLI performance is against nVidia's financial interests. They make more money from selling a top tier card than they do from selling a pair of 1070s. With the x70s showing 70% average and > 95% scaling in the tough games, twp x70s was a less expensive option for consumers and was casting nVidia cash. However such was necessary as they had to deal with 2 AMD cards in CF being a netter option than the top 1080 / 1080 Ti so they had to do well here. With no competition from AMD at this point in time, putting time and money into improved SLI performance was doubly counterproductive as the only cards subject to suffer decreased sales was the 1080 and 10890 Ti. So it's not unreasonable to speculate that until AMD releases the next gen cards, and assuming they do provide competition in this space, nVidia has little incentive to improve things here.
 
Solution

corndog1836

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corndog1836

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I wanted to reply directly to you but instead quoted you...sorry... THANK YOU FOR HELPING ME!!!!!!