TITAN X or 1080 SLI - disscused in depth

[CrazySajan]

Ok. I know most of the people here will say that SLI sucks but listen to me first

I mostly play AAA titles, but not right after the release date but later on - around 3-6 months. I like to wait for the developers to really fix the game and some extra DLC. Lets face it. All new games are bugged. So after a while the release SLI profile and even if they don't I can use NVidia inspector. And how many new released games don't support SLI? Deus Ex, Gears of war 4...for now? The only games that really sucks ass with SLI is Batman AK (which is so sad) and Just Cause 3 I believe. So by getting 1080 SLI I am beating the sh** out of Titan X.

And I don't want to wait for Ti because even if they show it in January, by the time it will available for normal prize in the store it will be march already.

Don't get me wrong, I love Titan X. But having 770 SLi for the last 2 or 3 years I only played 2 games using single GPU - The Evil Within and Wolfenstein series.

The new GPU that I will get will be used for 3440-1440 monitor with g-sync. My Cpu is 3930k and my PSU is 1200W. So what do you think???

 

[Mr Kagouris]

1080 SLI is the way to go. Titan X is just not worth it for the performance it offers.

 

[photonboy]

First off, SLI AFR can:

1) add latency
2) add stutter, or other glitches

The current trend in gaming engines is that AFR (Alternate Frame Rendering is how most multi-GPU works) is disappearing. The REASON is that they are finding ways to benefit from frames being so SIMILAR (which is similar to how video compression works).

Due to these similarities you need the same GPU to work on consecutive frames thus you can't separate them. Several people including Raja from AMD have been discussing this and it's going to become more COMMON.

Now SFR multi-GPU which involves multiple GPU's working on the same frame is the best way, but it's going to take about two years or so for that to start catching on since it's got to be built in to the gaming engine properly to really benefit.

*Since you have a GSYNC monitor then great. That makes things a lot easier as you don't have to aim for a specific FPS (i.e. if using VSYNC ON and trying not to drop below which adds stuttering).

Frankly, I'd just stick with a single GPU, then drop a couple settings if your FPS is dipping.

How good is 2xSLI (AFR)?
Even when it works the improvement varies a lot. Some are only about 20%, some as much as 90% but that's rare. Even when it's working, many of the tests show that the frame time issues actually LOWER the effective FPS.

It's difficult to properly SPACE out the frame times from each GPU which is one of the things the NVidia driver team attempts to do. When it doesn't work (which is more common if there's no support and you create an NVINSPECTOR profile) the first GPU may create a frame, then the second fairly soon after, then a longer GAP and a repeat of the process which then creates a JUDDERY experience.

TITAN X (P):
https://www.techpowerup.com/reviews/NVIDIA/Titan_X_Pascal/24.html

about 26% vs stock GTX1080

GTX1080 2xSLI AFR:
https://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080_SLI/20.html

a) 33% scaling with all the games; closer to 40% though at 3440x1440 (factoring in games that don't scale at all)
b) about 60% at 3440x1440 if using only the scalable games listed

So that's a hot mess, but let's again mention:

1) many games have no support so will run 26% faster on the Titan X (P)

2) *EFFECTIVE (or perceived) FPS is lower than what is reported for SLI unless it can perfectly spread out the frames.

3) Some of the reported frames can be RUNTS or late frames which are dropped (recorded but not shown)

4) best case AVERAGE of several games (ignoring "effective FPS) is about 1.7/1.25 = 36%

*So very roughly speaking, your getting about 36% boost for supported games on average (comparing 2x1080 vs 1xTitan X(P)).

If we factor in the unsupported games (which do about 26% better on the single Titan X(P), effective FPS, tweaking hassles and other issues then a 2xGTX1080 setup isn't nearly as good as it might appear looking at certain numbers.

And again, all indications are that AFR support is disappearing and that SFR is a ways off.

Summary:
I absolutely recommend avoiding multi-GPU. More specifically for you, I repeat I'd just use GSYNC and drop a few settings in a game if your FPS gets slightly low.

The settings that tend to kill the frame rate often add little visually to the experience anyway. Generally they are newer methods that will later be dropped or improved but otherwise are not very efficient.

(I've got a GTX1080 BTW so I've done a lot of tests and know what to expect)

Update:
The fact that a good GTX1080 is going to clock slightly higher than a blower-style will slightly skew the results but wouldn't change my opinion on multi-GPU. I'd get a single GTX1080, or wait for a GTX1080Ti.

Update:
On a 100Hz, GSYNC monitor I'd also consider CAPPING the FPS to the highest amount below 100FPS (95FPS?) that stays in asynchronous mode. Otherwise you're likely switching back to VSYNC which will add some slightly obvious latency in faster titles. In general though, VSYNC ON is fine for slower titles.

 

[photonboy]

Sorry for the above tome... but I wanted to be thorough and logical.

 

[CrazySajan]

Thanks for the great answer. Now I am even more confused. I thought I like Titan x even more but now I found some issues about keeping this card cool. I hate to spend another 200$ for good water block and few hundred more for custom water cooling system. But on the other hand my CPU is water cooled and I have Cooler Master HAF X Big Tower with fans all over. Do you think I may have overheating issues? I hate to have GPU fan running at 100% but 60%-70% may be reasonable. What do you think?