SLI and 1440p problems, help please

wyattschiffer

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Nov 14, 2017
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I recently got a second GTX 1070 8g OC edition and SLI'd it with another identical card.

I had set up the SLI and, on my 23" 1080p 60hz monitor, I was getting anywhere from 58 to 144 hz playing PUBG (which I know is pre-release and has minor SLI issues in menus, but bear with me). Although the 144 was rare, it was enough for me to want to go ahead and get a new monitor. I also was suffering some screen tearing and stutter, and after messing with v-sync, adaptive sync, and a number of other settings, I decided going to 144hz monitor was a jump I was ready to make.

While I was spending the money, I also decided to get a 1440p monitor. I ended up with an ASUS MG278 monitor ( https://www.asus.com/us/Monitors/MG278Q/ ) Which yes I know has freesync, not g-sync, but I wasn't concerned with that function I just wanted the 144hz, 1440p.

I take it home, set it up, kick it on, set it up in Nvidia control panel, make sure everything is correct and running how it should, it all looks good and smooth, no problems (watched a few 1440p youtube vids etc.)

Then I decide to try that good good PUBG.

Set it to 1440p in in-game settings.

Get into game, and bam: 30 fps, choppy, dropping down to 9 fps, then in some cases up to 70, then hard back down to 30, 12, 26... Very erratic, very unplayable.

I already play with all my settings down to as low as possible so after a while of frustration, I change my rez in game back to 1080p. Nothing changes... I try 720 even... slightly better by 5fps or so...

I turn on MSI Afterburner and jump in another round. I start seeing that my two cards are only running between 15% and 40% each, jumping around about as erratically as the framerate was. I don't understand, I never had this problem before I hooked up the new monitor and started running it at 1440p, even when on SLI.


My comp is
CPU: i7 7700 clocked at 4.5
MOBO: Gigabyte z270x
RAM: 32 gigs ddr4 4200mhz (it was a gift)
GPUs: 2x GTX 1070 8g OC edition (in sli)
PSU: Thermaltake 1200w


My big questions are:
1. Is 1440p REALLY too big a jump for my SLI 1070s, and should I just expect this? If the fps is lower than usual then sure I get it, but the crazy erraticness makes it so crazily unplayable
2. What on earth is making them throttle so hard now that they're trying 1440p when they were both fine with 1080p (going up to 95% load each and being totally fine performance/heat wise)?
3. When I run Furmark at the 1440p setting while in SLI I get between 115 and 150 fps, what is suddenly tripping out my cards with PUBG?
4. My GPUs are daisy chained with their pci cables - 1 card, to the 2nd card, then into the PSU. Could this be a problem of the cables not handling the load? Wouldn't that show up during the furmark?

Please help me, Really dunno what to try next :/
 
Solution
No idea, but honestly chances are a game wont use SLI well, that's why most people are just buying beefier cards then messing with it. Nvidia seems to use it more for a marketing plow then anything now and game developers don't want to spend the time or money to implement it well since most their customers don't have it. Plus it doesn't help many games are now ports of console development.

I would run the benchmark I linked to make sure you are getting SLI performance correctly since games are so hit or miss.

If it is SLI causing bad performance just do like I said and disable it in the Nvidia Control Panel for the games its causing problems with.


So I opened up the case, popped out my second card, made sure the first one was plugged in snug. and closed it back up.

Turned it back on, turned on fine, jumped into pubg to test again, I got consistent 50 fps, some jumps to 40 some jumps to 60.

The card was running at an even 1.05volts, an even temp of 55c or so, and an even clock speed, although I think my voltage tanked a bit when I got into a firefight.

Again, I had the cord from the psu daisy chained from one card to the second due to a lack of cables. This was before I took the second card out just now, now it's just the cable connected to one card.
 
Two causes:
1) Not enough power is being fed to the cards
2) SLI is not working good for this game

let's eliminate point 2. Put your graphics card back and run any other game that you have and you know runs well in SLI and check (you will have to google a bit for this). If it works, PUBG is the issue. If it doesn't, point 1 is the issue.

PUBG is still in early access and is still not properly optimized and thus, is a very poor choice to classify an issue as a hardware issue.
 


I ran Furmark again on the 1 card, 1440p still, and the Voltage is going anywhere from 1.05 down to .825, is this fluctuation normal? Do you think the daisy chain cords are the reason they're not getting power? Is this the case even when I'm using that cord on just this one card?
 


You playing on just the one card?
 
1060 doesn't support SLI, so yes he is playing on one card. :)

That voltage fluctuation looks normal as the graphics card would only consume as much power it needs. However, please double check with MSI afterburner if there is any thermal throttling. You can also use GPU-z for this. There is a sensor called "perfcap reason", that you can take a look at. its highly unlikely but worth a check.

And, to be honest, I still don't understand daisy chaining of PSU cables. Your PSU is 1200 W and it should have at least 2 x (6+2) pin connector, maybe even 4. My 520W PSU has 2x (6+2) pin connectors. So, if I were to SLI a 1070 on my PSU hypothetically, I would connect one cable in one card and the second cable in the second card.
 


I haven't a clue where my spare psu cables went, so after getting my 2nd 1070 I realized my cord connected to the first one had an attached 6+2 that I could use. Up until tonight everything was working fine so I didn't see it as a problem. But I'll probably have to order one secondhand online to be sure.
 


Put the card back in, loaded up fine, jumped into Overwatch and got consistent framerate, anywhere from 52 to 88, this was with SLI enabled. Unfortunately once again, the cards were only going to 55% of their usage max, most of the time it was 45% and sometimes as low as 23%. Is Overwatch really not SLI optimized too?
 
No idea, but honestly chances are a game wont use SLI well, that's why most people are just buying beefier cards then messing with it. Nvidia seems to use it more for a marketing plow then anything now and game developers don't want to spend the time or money to implement it well since most their customers don't have it. Plus it doesn't help many games are now ports of console development.

I would run the benchmark I linked to make sure you are getting SLI performance correctly since games are so hit or miss.

If it is SLI causing bad performance just do like I said and disable it in the Nvidia Control Panel for the games its causing problems with.
 
Solution


Hey man, good news, your setup is fine. Overwatch is not a particularly demanding game and the behavior is completely normal. I would go so far as to say that if you disable SLI in ontrol panel for Overwatch, you will notice much more frame rates.

Going SLI just enables performance boost in like 5% of the games. More often than not, it brings more issues than it brings the advantages.

TLDR: Your setup is fine and is performing as expected. happy gaming!
 


Either SLI doesn’t work well in those games or something is screwed up. I have a single 1070 paired with an i5 4690k on a 1440p 144Hz gsync monitor. With ultra settings and a 100% render scale I get 130+ FPS in Overwatch. 52 to 88 FPS in Overwatch is pretty terrible for your hardware.