mugurumakensei
Member
is ambient occlusion enabled?
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GeForce GTX 970s seem to have an issue using all 4GB of VRAM, Nvidia looking into it
- Thread starter Naked Snake
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is ambient occlusion enabled?
Well at 4k yes I would expect stuttering but I'd be saying that even if I had no idea about this whole issue
With a single 970?
mugurumakensei
Member
Psyrgery ES
Member
Yeah, I hope it can be fixed somehow. Got this card last month and it would be very annoying if it ends up being gimped
FunkyMunkey
Banned
In those threads some people have linked on here to various forums, people have actually been showing this in games with very high vram usage (skyrim heavily modded, etc). The bandwidth in the 970 tanks 90% or more when 3.5GB vram is hit while the 980 stays consistent until 4GB. That is a huge problem (unless I'm misreading which is completely possible
).Most people didn't buy the 970 to play older games at 120fps (well I'm sure some did, especially at insane resolutions) but to be relatively future-proof for the next few years. Losing out on 12% of the vram in the card is false-advertising. There are a ton of games coming out that will absolutely push these cards to that limit and beyond, not even counting VR and such.
I've got Unity up and running on those settings with a 30 FPS cap on my SLI 970s and am seeing VRAM usage fluctuate between 3800-4000 MBs. It is not consistent at all, moving around and fighting is revealing frequent mini freezes/hitching very briefly seen as a dip to ~27 FPS. GPU usage is below 99% on both cards like this and the stuttering is very characteristic of VRAM limitations. I see a brief frametime spike according to MSI Afterburner at the same time as those FPS dips up to around 37 ms and that might not be accurate enough still given how quickly the stuttering comes and goes.
I'm very clearly getting VRAM-related stuttering here; most of the time at my usual resolution of 2560x1440 using FXAA my VRAM usage doesn't exceed ~3600 MBs and I don't get these types of stutters nearly as frequently, even though my GPU usage is often higher and my FPS as well (I don't cap to 30). I'm on the last drivers before the 960 update ones were released yesterday and on the latest patch with Unity. Does Uplay have a screenshot function that'll record overlays?
Edit: seeing 50-65 ms occasionally running around rooftops.
mugurumakensei
Member
I typically use fraps for the purpose of screenshotting overlays.
Dictator93
Member
Why would ambient occlusion cause stuttering?
Stuttering is GPU stalls either from a bad SLI implementation, going above and beyond VRAM limits, or the engine being shit. Stuttering does NOT occur at 4k with a 980 or a 290 series card in Ryse (the framerate is just low), yet it does occur, at least on my brothers rig, with 2x 970s (which have waaaaaay more shading power) in Ryse. I am inclined to imagine that that problem described in the OP is affecting him.
dr_rus
Member
In those threads some people have linked on here to various forums, people have actually been showing this in games with very high vram usage (skyrim heavily modded, etc). The bandwidth in the 970 tanks 90% or more when 3.5GB vram is hit while the 980 stays consistent until 4GB. That is a huge problem (unless I'm misreading which is completely possible
Most people didn't buy the 970 to play older games at 120fps (well I'm sure some did, especially at insane resolutions) but to be relatively future-proof for the next few years. Losing out on 12% of the vram in the card is false-advertising. There are a ton of games coming out that will absolutely push these cards to that limit and beyond, not even counting VR and such.
What are they showing? How can they show that a "bandwidth tanks"? Bandwidth is a peak achievable number, it can't "tank" in very much the same way as a gas tank of a car can't "tank". We need to see the comparison of performance of 970 and 980 in these cases, not some anecdotal evidence of a CryEngine3 game stuttering on 970 at 4K resolution.
I haven't seen any benchmarks suggesting that 970 has a problem with high memory utilization. People bought their cards because they saw benchmarks and decided that it was worth the money. These benchmarks are real and that test is fishy, not the other way around. That's why I'm saying that we need a proof of this in real world games or at least compute apps. It shouldn't be difficult to get such proof if all 970 are affected and all 980 aren't. Up until now all I see are screenshots from a benchmark which doesn't even benchmark fps or frametimes - just some chip bandwidth.
Again - a game which is showing to be using all 4 GBs of VRAM SHOULD stutter as this means that it is actually went above the card's VRAM pool and is trashing data through PCIE bus. What we need is a game which will stutter on 970 and won't on 980 while using 3.9 GB of VRAM.
Can't you turn off SLI and check again?
mugurumakensei
Member
?
970 maintains a much more consistent albeit higher frametime than a 290 in ryse at 4k.
JimmyRustler
Gold Member
So, am I right to think that this is pretty much a non issue if you only play your games with FullHD?
Dictator93
Member
I am not by my brothers PC any longer (I am an entire continent and ocean away in distance). But I did test to see if it was an SLI problem when I was there (that is what I immediately tried out actually) and it was just as juttery (albeit it at a lower avg framerate when it wasnt stuttering).
Naked Snake
Member
It can be in certain games if you use like 8x MSAA, or likely even without that in future games.
I've monitored and logged both of my GPUs' usages, VRAM usage per card, FPS, and frametimes and made graphs of them with excel while briefly running and looking around Paris in AC: Unity. Here are the results. Note that GPU usage on both cards remained below 99%, VRAM usage remained below 4096 MBs (though it did get close), and frametimes are all over the place once in the game (30 FPS is 33.3 ms, clearly going way above that). FPS is also capped to 30 FPS as you can see:
This doesn't necessarily demonstrate the 970s' issue because of how high VRAM usage got here, but Unity doesn't seem to be doing so hot as evidence against the issue. This is at 1920x1080, max settings, and 8xMSAA and looks like one of those extreme situations that force my 970s to use over ~3600MBs/3.5 GBs. Most of the time I get this kind of stuttering without exceeding 3.5 GBs.
iN1njaCPFC
Member
From that picture it looks like you're getting stuttering but not the issue of not being able to utilise the full VRAM?
Dictator93
Member
The issue is that when it is above 3.5 gigs or so, it stutters.
It's not that the 970s can't ever use more than 3.5 GBs, it's just that most of the time even when it could benefit from it, it doesn't. Extreme situations such as 8xMSAA with Ultra textures on AC Unity is enough to force it to use more, but it's not performing smoothly in that case either and most of the time my 970s try to avoid overfilling 3.5 whereas a 980 would just use more and have less/no stuttering.
Every time I've ever exceeded ~3600 MBs in any game or just pushed up against that limit, I get similar stuttering regardless of by how much.
iN1njaCPFC
Member
Ah right, seems I misunderstood the issue. If the issue is that the memory is there but seems to stutter, surely that's a driver issue?
You did not run it headless or windows basic theme, hence crash.
No, the bench shows the last 500Mb can only be accessed at degraded bandwidth, hence the 970 driver is choosing to only use it as a last minute resort. And when it does the whole game stutters badly.
The reason why the driver is probably setup like this is because nVidia knew the hardware was gimped.
This is why in Watchdogs the 980 allocated 4Gb, the 970 3.5Gb at the same settings.
Users also note that as you pass 3.5Gb usage the GPU usage drops too. Indicating the 500Mb that is at really low bandwidth is bottlenecking the GPU core.
Femmeworth
Banned
Good thing I haven't bought a 970 yet. :x
Yeah, I just read that.
But I did the testing in AC:U now:
You clearly see the fps drops while the memory usage remains about the same.
Everything's maxed out afaik.
The ingame resolution was 1440p DSR by Nvidia and when you look at the FPS graph you can see the frames going crazy low as i turn in the AA. Its from FXAA --> 2 MSAA and as I approach 4 MSAA and TXAA it drops to at about 5 frames and below... unplayable.
Now my question is if simply the card is at it's limit or if I'm affected by that bug?
Damn, I was actually planning on saving up for one of these in the coming months. I really hope it gets sorted out because I can't really afford going higher and I can't really justify buying a 970 if there are known issues with it either. :/
I need to replace my case first so it's not like I was in a hurry to order but I really hope this gets resolved quickly. Otherwise I might have to look into whether a 960 would be a reasonable enough upgrade from my current card.
I need to replace my case first so it's not like I was in a hurry to order but I really hope this gets resolved quickly. Otherwise I might have to look into whether a 960 would be a reasonable enough upgrade from my current card.
Hey sorry if this is a bit off-topic but what program(s) do you use to monitor and graph your performance info like that? Right now I use RTSS with HWINFO64 which works well as a real-time overlay, but idk how I'd get it to log info like that. I'm a GTX 970 owner as well, so I'd be really interested to run some tests if I can get a workable setup.
MSI Afterburner. It has RTSS bundled in with it for the OSD and MSI AB will display the graphs in real time in the background.
You should be able to log it to a file, then he has made tables in Excel and created a graph.
cheezcake
Member
The cut SMM theory makes no sense to me. If it really is only a 208 bit effective bus there must be some NVIDIA voodoo going on coz we know all 4GB is addressable and that's not the issue, and the performance cutoff seems to be consistently above 3.5GB VRAM in gaming scenarios not 3.3GB VRAM.
wanderingprostheyltite
Member
Well this is a bummer especially after seeing Serandur and LilJoka's posts, was really hoping it was something that could be fixed with a firmware/driver update
Really hope Nvidia steps up to the plate and does the right thing here, offering at minimum some sort of discount program for future gpu purchase or game(s). Not expecting much though unless this issue really gains traction at the bigger sites.
Really hope Nvidia steps up to the plate and does the right thing here, offering at minimum some sort of discount program for future gpu purchase or game(s). Not expecting much though unless this issue really gains traction at the bigger sites.
Ok I tried to followed your guide and this is what I got on my Palit Jetstream 970.
First line is 1440p with 2x msaa and barely hitting 4000, was around 3900 - 4000 depending on the situarion.
second line is 1080p with several AA settings. It was about 3500-3700 RAM usage.
last part is parity-resolution of 900p with no AA enabled.
Can you make anything out of this?
Also tried Titanfall for a longer period but it did not go above 3500 Ram
Thanks
The 970 is so fast, it gets 1 Jillion gigabytes / sec
themadcowtipper
Smells faintly of rancid stilton.
Great Scott
ussjtrunks
Member
At least we know why nvidia locked it to 3.5gb its to save it from tearing a whole in time & space D:
It just has to fill up Memory. And it was successfull
It needs to fill up memory and then show a noticable, reproducable behavior like stuttering. How do you measure performance in a game with constant performance issues. Makes no sense.
Naked Snake
Member
It doesn't have constant performance issues. I'm sure the game has areas that are normally stable and can be tested in.
themadcowtipper
Smells faintly of rancid stilton.
The title screen?
Of course it has. And even if it doesn't how would you tell them apart if there are issues. Its just not reliable. If you want to test that issue, yyou need a game which runs at rock solid 60fps normally even at 4k and you still need to be able to get above 3,5gig vram...good luck.
Hip Hop
Member
where?
themadcowtipper
Smells faintly of rancid stilton.
People really believe they are going to get a upgrade to a 980 out of this???
That is Drug addict Andy Dick Crazy...
That is Drug addict Andy Dick Crazy...
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