WCCftech: Memory allocation problem with GTX 970 [UPDATE] PCPer: NVidia response

[skipsneeky2]

Been trying hard not to comment in this one,tractor beam sucked me right in.I'm to casual to catch all the technical details but the prime beef is a apparent disabling of some of the 970s memory giving it really less then 4gb usable?

Never really seen so much bs on Anandtech in the gpu section before,there's Kepler gimping to make the 970/980 look better off then you get the 970s which aren't true 4gb cards?The Kepler gimping could be true as its all about the mothertrucking money but this memory debate is out of this world.

Scotty,beam me out of here!

 

[el etro]

Have that site ever been anything but a joke?

No.
Never was other thing.

 

[cmdrdredd]

Been trying hard not to comment in this one,tractor beam sucked me right in.I'm to casual to catch all the technical details but the prime beef is a apparent disabling of some of the 970s memory giving it really less then 4gb usable?

Never really seen so much bs on Anandtech in the gpu section before,there's Kepler gimping to make the 970/980 look better off then you get the 970s which aren't true 4gb cards?The Kepler gimping could be true as its all about the mothertrucking money but this memory debate is out of this world.

Scotty,beam me out of here!

The prime argument is the GTX 970 is advertised as having a 256bit memory interface but the 970 can't load up all of it's memory because it is not using a 256bit interface and Nvidia is lying.

 

[skipsneeky2]

The prime argument is the GTX 970 is advertised as having a 256bit memory interface but the 970 can't load up all of it's memory because it is not using a 256bit interface and Nvidia is lying.

Those are huge claims.Interesting enough to me as a 970 buyer coming up soon.

 

[cmdrdredd]

Those are huge claims.Interesting enough to me as a 970 buyer coming up soon.

Well, if I go above 1440p I can use close to 4GB in many games. At 4k and high levels of AA I can go above 4GB and lock up the game. I don't see a problem. I expect if I had a 290x or GTX 980 or even a older 4GB card I could do the same.

 

[el etro]

Wccf don't even know what are they talking, guys...

 

[skipsneeky2]

Well, if I go above 1440p I can use close to 4GB in many games. At 4k and high levels of AA I can go above 4GB and lock up the game. I don't see a problem. I expect if I had a 290x or GTX 980 or even a older 4GB card I could do the same.

That is funny,sounds like you were really trying to debunk this one with 4k and high levels of AA.Performance has to be piss poor with recent games at 4k with AA wouldn't it even in sli on your 970s?Where does the memory usage land typically with settings you would use?

I guess the conspiracy needs more tin foil,i can safely assume your running OSD more times then not,unless #illuminati decided to tamper with OSD like rivatuner then this whole freaking thing is hot air.Confirmed 4gb usage by OSD should mean just that?

 

[cmdrdredd]

That is funny,sounds like you were really trying to debunk this one with 4k and high levels of AA.Performance has to be piss poor with recent games at 4k with AA wouldn't it even in sli on your 970s?Where does the memory usage land typically with settings you would use?



I guess the conspiracy needs more tin foil,i can safely assume your running OSD more times then not,unless #illuminati decided to tamper with OSD like rivatuner then this whole freaking thing is hot air.Confirmed 4gb usage by OSD should mean just that?

The claim was at 1080p maxed settings it should use 4GB because the 980 does but the 970 can only load up to 3.6GB. I tried that and it was well below 4GB and actually only went up to around 3.5GB. Another user with a 980 noted that they didn't see 4GB usage with the same settings. In order to get to 4GB I need way higher than 1080p resolution. My conclusion is that someone is not being truthful about the settings in use.

Performance wasn't the concern. The concern was that the Gtx 970 can't use all 4GB of memory which I disproved while at the same time we proved that at 1080p in FarCry 4, the memory usage does not approach 4GB at all. Yeah at 4k it's not playable with AA but that's how I max out the vram just for this. I wouldn't play at 4k even without AA. It is a little too demanding yet.

I don't use the OSD a lot but I did turn it on to see if there was any truth to this. The problem is two members here found memory usage to be far lower than claimed at 1080p and to get the usage the OP claimed at 1080p with a 980, requires much higher resolution.

 

[skipsneeky2]

Good and plenty convincing conclusion there Cmd Another clickbait link that got just one more click from me.

I know i have left my browsers open when i game,especially Battlelog in Chrome when i play BF4 and i notice a good 200mb vram can be used up often times just by Chrome.Maybe open browsers and tabs are accounting for the wildly varying vram numbers?

I know my theory is way to easy but i found this out myself not to long ago,i was often leaving my browsers open when i game.

 

[RussianSensation]

Unless 970 shows adverse performance (stuttering or reduced FPS), this sounds like an unsubstantiated claim that it can't use the full 4GB of VRAM. More interesting is that AMD and NV cards respond differently to VRAM overloading. In WTNO for example, NV's 1.25-1.5GB cards completely tank while HD5870 1GB can still play the game. In some games NV uses VRAM more efficiently and in others it's AMD.

I don't think GTX970 owners have much to worry about unless we see reputable sites/reviewers showing some major differences in real world gaming performance in cases where a game actually requires 4GB of VRAM.

 

[cmdrdredd]

Well I would say that at some settings, far cry 4 and dragon age inquisition both require 4GB as they go over 3GB. At lower AA settings or different resolutions it changes obviously. I don't think there are many games that really need that much vram at 1080p.

 

[ShintaiDK]

You have to select crazy stuff in FC4 to get that high. Without, even a 2GB card is more than plenty.

 

[Rvenger]

First I have ever heard of this issue. My cards seem to be working fine.

 

[flexy]

All I read on the net about this issue (whether it be just a major troll or based on reality) is long flaming threads AND NO SUBSTANCE.

Whether a game in a certain resolution "can not even get to almost 4GB Vram usage with 8xMSAA" shall be irrelevant.

What stands is a claim, and this claim I would like to see either proven wrong or right.

The claim is that GTX 970, once allocating over 3.5Gb is suffering a severe, "unnatural" performance hit...which would have the same effect as if the the card had only 3.5VMem ( and then would require to use system memory/pagefile for this remaining chunk of memory )

Don't tell me that with DSR and downsampling from crazy resolutions and then some MSAA settings it's impossible to reach close to 4GB VMem usage, say, 3.8 or 3.9

The claim could be proven wrong or right by selecting such resolutions (use DSR!) and then observe a possible PERFORMANCE DROP comparing GTX 980 and GTX 970 under this condition with settings where Vmem usage is still BELOW this alleged 3.5GB treshold. Of course this performance drop must be significant and should (if the claims are true) only happen on the GTX 970 and must be a much bigger performance drop than seen on the GTX 680.

**

I have seen some people arguing the alleged issue is a non-issue, but I beg to differ, especially if we're talking about DSR which is ONE main reason I would actually want a 970/980...even on a "small" monitor. And I think it WOULD matter if indeed 500MB would just not be available (as is claimed) if we're talking about downsampling. It might be exactly those 500MB "missing" (or inaccessible, whatever) that could make all the difference in performance from 4K downsampling.

 

[Head1985]

Well it turns out GTX970 isnt 256bit its actually 208bit card
http://www.overclock.net/t/1535502/gtx-970s-can-only-use-3-5gb-of-4gb-vram-issue/170

From the Nai's Benchmark, assuming if the allocation is caused by disabled of SMM units, and different bandwidth for each different gpus once Nai's Benchmark memory allocation reaches 2816MiBytes to 3500MiBytes range, I can only assume this is caused by the way SMM units being disabled.

Allow me to elaborate my assumption. As we know, there are four raster engines for GTX 970 and GTX 980.
Each raster engine has four SMM units. GTX 980 has full SMM units for each raster engine, so there are 16 SMM units.

GTX970 is made by disabling 3 of SMM units. What nvidia refused to told us is which one of the raster engine has its SMM unit being disabled.
I found most reviewers simply modified the high level architecture overview of GTX 980 diagram by removing one SMM unit for each three raster engine with one raster engine has four SMM unit intact.

First scenario
What if the first (or the second, third, fourth) raster engine has its 3 SMM units disabled instead of evenly spread across four raster engine?

Second scenario
Or, first raster engine has two SMM units disabled and second raster engine has one SMM unit disabled?

Oh, please do notice the memory controller diagram for each of the raster engine too. >.< If we follow the first scenario, definitely, the raster engine will not be able to make fully use of the memory controller bandwidth

64bit memory controller, total 4 memory controllers = 256 bit memory controller.
Assuming if there are 3 raster engines with each three has one SMM disabled leaving 1 raster engine with 4 SMM intact.
Mathematically ;
16 SMM = 256 bit = 4096 Mb
13 SMM = 208 bit = 3328 Mb

208 bit = effective width after disabling SMM with 256 bit being actual memory controller width

 

[Ranulf]

So yeah..

https://forums.geforce.com/default/topic/803518/geforce-900-series/gtx-970-3-5gb-vram-issue/1/

 

[RampantAndroid]

I'll be interested to see NV's response...

 

[iiiankiii]

Wth. This is not looking good. I feel a lawsuit coming.

 

[Erenhardt]

Wth. This is not looking good. I feel a lawsuit coming.

You still get full 4GB of VRAM, just part of it is un-usable.

 

[Head1985]

it looks like i was right from the start

 

[Carfax83]

So if I'm reading those benches right, the GTX 970's L2 cache and memory bandwidth both start falling off when 3200 MB of VRAM has been accessed?

But I play games all the time that go over 3200 MB without any performance issues

So either that benchmark is lying, or my GTX 970s are "special" :sneaky:

Also, here's the GTX 980 manifesting the same issue:

 

[Flapdrol1337]

from a neogaf thread
http://www.neogaf.com/forum/showthread.php?p=148763930#post148763930

Maybe try running it with windows aero (or the win8 equivalent) turned off.

edit: too late

 

[Head1985]

They run test wrong

Only GTX 970 is affected, over 3.5GB slower. I have seen GTX 770, Titan, 980 etc results. All are fine. Safest thing is you test it while iGPU is in use. GTX 970 VRAM usage should be 0MB before you run the benchmark. Win 7, 8 10 doesn't matter.

 

[Gloomy]

The last 300 or so MBs is Windows hardware acceleration. You need to run the test headless or with Windows running on the iGP for it to be accurate; Windows uses about 300MB of VRAM.

Which is why that 980 starts screwing up early.

 

[guskline]

My GTX970 works fine!