AC in 4k@60hz - Problem

[Craig Turner]

I am pulling my hair out here why my system won't run AC in 4k smoothly?

Spec:

1. Win 10 Pro 64 bit
2. I7 3960x @ 3.3GHZ
3. RAM – 16GB DDR3 @ 666 MHZ
4. NVIDIA Geforce GTX 1070 4095 MB (Edit: It is actually 16gb)
5. Samsung 850 EVO SSD – 1TB
6. Monitor - 40" JVC 4K Ultra HD TV

No matter how low the settings, it seems to run 'choppy' but still shows as 60FPS, and this is just in singlepayer ?
Is there something that may be causing this, as I am sure my specs should be able to manage it shouldn't they?
I can run everything at max in 2k with no issues, soon as I select 3840 x 2160 it turns choppy.

Any advice on this is most appreciated as I have spent most of the weekend trying to sort this out.

 

[Craig Turner]

VRAM is fine actually, and yep running in 64bit mode

 

[Case_]

Surely you jest? I had no idea that this would be a thing...

Nope, there was quite a fuss about it when the 970 was released, it's a well known issue. They did manage to work around it pretty well in the drivers as time went on, but it still absolutely exists to this day, because it's some kind of limitation of the card's design.

I believe this was also the reason why the 1060 was introduced as a 3GB card originally instead of a 4GB (because it would suffer from the same issue if it had 4GB of VRAM and they didn't want to go there again, so they simply used less memory to begin with), and why the 6GB cards now exist (as they basically just added an additional memory controller and another 3GB of VRAM), but don't quote me on that.

 

[Neilski]

Nope, there was quite a fuss about it when the 970 was released, it's a well known issue.

Fair enough. Still stunned but hey, it keeps life interesting(!). I would probably have known about it myself I guess if I had actually bought my 970, instead of being given it by a friend who had moved on to the 10 series...

 

[Craig Turner]

As mentioned above its 16gb

 

[RasmusP]

As mentioned above its 16gb

*8gb
The shared memory doesn't count as it's not part of the graphics part but only an available extension from the CPU system RAM.
It's only there to... basically instead of the application crashing it will just start to stutter.

But you are right that is absolutely doesn't matter for your case and problems since 8GB are plenty enough!

Still strange though were the problem lies then...
Are you sure that you're not just hitting the GPU load limit and see fps drops? Maybe it's so on the edge that the fps counter shows 60 but actually fluctuates a little. Even when I put everything to low my 1070 wasn't really "enjoying" 4k.

One thing I can think of: How is your monitor connected to your PC? What Monitor do you have btw? Is it running at different Hz for Assetto Corsa than it is in other games or on the Desktop?
Can you run other games in 4k without problems? Is your Desktop set to 4k?

I'm asking because there might be a connection problem. My 120 Hz 3440x1440 with the 'old' G-Sync module running through DisplayPort 1.2 is borderline stable!

Do you run multiple monitors? And if so, how are they "aligned" with the rest. Next to each other, up and down.. And what's the resolution of them?

Feel free to say "screw this I just won't play in 4k". Just wanted to get back on topic and push for a solution

 

[Craig Turner]

Lots to answer there:

Ok so,

Today I ran PC2 and Dirt Rally - no issues in full 4k with high settings

I run a TV - JVC 40", HDMI 2 direct to PC.

I do have 3 other desktop monitors, but I use 'Monitor Switch' to switch from desktop mode to Sim Pod mode, so it turns those 3 off totally, I then check the desktop is in 4k also on the JVC monitor, sometimes needs a manual change.

So it seems as though the bottleneck is with AC in my view (Even though with a 60fps cap - I get a constant 59fps, even when it stutters in game, it still says 59fps), and I really don't want to have to do a fresh install, with all the mods, configs etc I have built up.

 

[Case_]

Have you tried recording the stutters, if they show on video? Might give us a better idea, especially if you include the GPU and CPU stats with it (can easily be done with Afterburner).

Also, what are your in-game settings? Are you running fullscreen or windowed? AC has a nasty habit of switching to windowed mode, at least in my experience, and that might cause various stutters, also depending on how your vsync is set.

 

[RasmusP]

Lots to answer there:

Ok so,

Today I ran PC2 and Dirt Rally - no issues in full 4k with high settings

I run a TV - JVC 40", HDMI 2 direct to PC.

I do have 3 other desktop monitors, but I use 'Monitor Switch' to switch from desktop mode to Sim Pod mode, so it turns those 3 off totally, I then check the desktop is in 4k also on the JVC monitor, sometimes needs a manual change.

So it seems as though the bottleneck is with AC in my view (Even though with a 60fps cap - I get a constant 59fps, even when it stutters in game, it still says 59fps), and I really don't want to have to do a fresh install, with all the mods, configs etc I have built up.

Seems like it's all okay then..
Might be the windowed mode thing Martin mentions...

Fresh install won't help, don't spend a thought about that. I think it's time to do:
- Screenshots of every graphic setting
- monitor what's going on. Openhardwaremonitor can show a plot that records everything nicely and doesn't need to be installed, msi afterburner package with riva tuner would be even better as you can see the stats while in the game via overlay. We would need: GPU frequency, GPU load, fps and "frametime". FPS and frametime are only available with msi afterburner though.

 

[Deleted member 197115]

Did you try settings I suggested on first page
Set fps limit to unlimited and use VSync in Nvidia.

 

[budgetek]

I had a similar problem on my high end rig (i7 8700k, rtx 2080ti, 32 gb ram, Asus Z390-F gaming). I had heavy stutter in AC at 120+ fps (tripples, 3x1440p). AC was installed on nvme ssd Samsung 970 Pro while Windows 10 and other sims were installed on nvme ssd Samsung Evo. After some time I tired moving AC to Samsung Evo and AC started to run butter smooth. I believe there was a problem of second M2 slot sharing some bandwidth with gfx.

 

[Case_]

I believe there was a problem of second M2 slot sharing some bandwidth with gfx.

There shouldn't be, BTW. Your GPU should be using CPU PCIe lanes, while the M2 should be using chipset PCIe lanes.

 

[Craig Turner]

@ Andrew, yes I changed those settings

 

[Craig Turner]

Settings:

 

[RasmusP]

Settings:
View attachment 304886

Do you have vsync put to adaptive in the nvidia settings?
If so uncheck "limit framerate".

Adaptive vsync doesn't like locked fps at the Hz value. For me that always results in tearing and stuttering.
Normal vsync sometimes runs better, sometimes worse with a fps limit.

 

[Craig Turner]

ok will try that now also

 

[Craig Turner]

Ok so using these settings and MSI Afterburner, this is the best I can get so far in 4k:

 

[Craig Turner]

Video of Replay

 

[RasmusP]

So what did you change regarding vsync? I still see the frame rate limit being checked and at 60 fps. Did you change vsync to normal in the nvidia settings or is it still at "adaptive"?
Your gpu is totally fine at 59 percent load so there's definitely something inducing the stuttering not performance related.

I wonder about the cpu temperature a little bit though. 78 degrees at only 17% load? Do you run such a flat fan curve that it goes up that far?

Please report back about your nvidia settings, about the cpu cooling situation and additionally: check the gpu Frequency. I see the cpu is running at 4.4 GHz, what's the 1070 at? With only around 60% load it might be throttling. Please check if its above 1500 MHz while running assetto

Also: do you run a lot in the background? 8.4gb ram used seems a bit much for just assetto corsa. Might be totally fine though!

And a last thing: did you try to hit alt+enter while on the track? Nvidia vsync (all of them) will only kick in if the game runs in fullscreen. Ac likes to jump into windowed mode as mentioned, which would also deactivate vsync and therefore stutter.

 

[Case_]

Yeah, good catch, that CPU temperature really does seem quite suspicious.

And yes, the stutter looks a lot like what I experience in windowed mode.

 

[Deleted member 197115]

- Remove framelimit
- NVidia Adaptive Vsync
- Max prerendered frames = 1

Try with that and report back.
And one more, set refection frequency to static, it can hog CPU quite a bit.