Monday, January 26th 2015
NVIDIA Responds to GTX 970 Memory Allocation 'Bug' Controversy
The GeForce GTX 970 memory allocation bug discovery, made towards last Friday, wrecked some NVIDIA engineers' weekends, who composed a response to what they tell is a non-issue. A bug was discovered in the way GeForce GTX 970 was allocating its 4 GB of video memory, giving some power-users the impression that the GPU isn't addressing the last 700-500 MB of its memory. NVIDIA, in its response, explained that the GPU is fully capable of addressing its 4 GB, but does so in an unusual way. Without further ado, the statement.
Source:
The TechReport
The GeForce GTX 970 is equipped with 4GB of dedicated graphics memory. However the 970 has a different configuration of SMs than the 980, and fewer crossbar resources to the memory system. To optimally manage memory traffic in this configuration, we segment graphics memory into a 3.5GB section and a 0.5GB section. The GPU has higher priority access to the 3.5GB section. When a game needs less than 3.5GB of video memory per draw command then it will only access the first partition, and 3rd party applications that measure memory usage will report 3.5GB of memory in use on GTX 970, but may report more for GTX 980 if there is more memory used by other commands. When a game requires more than 3.5GB of memory then we use both segments.Continued
We understand there have been some questions about how the GTX 970 will perform when it accesses the 0.5GB memory segment. The best way to test that is to look at game performance. Compare a GTX 980 to a 970 on a game that uses less than 3.5GB. Then turn up the settings so the game needs more than 3.5GB and compare 980 and 970 performance again.<div class="table-wrapper"><table class="tputbl hilight" cellspacing="0" cellpadding="3"><caption>GTX 970 vs. GTX 980 Memory-Intensive Performance Data </caption><tr><th scope="col"> </th><th scope="col">GeForce <br /> GTX 980</th><th scope="col">GeForce <br /> GTX 970</th></tr><tr><th scope="row">Shadow of Mordor</th><td align="right"></td><td align="right"></td></tr><tr class="alt"><th scope="row"><3.5GB setting = 2688x1512 Very High</th><td align="right">72 fps</td><td align="right">60 fps</td></tr><tr><th scope="row">>3.5GB setting = 3456x1944</th><td align="right">55fps (-24%)</td><td align="right">45fps (-25%)</td></tr><tr class="alt"><th scope="row">Battlefield 4</th><td align="right"></td><td align="right"></td></tr><tr><th scope="row"><3.5GB setting = 3840x2160 2xMSAA</th><td align="right">36 fps</td><td align="right">30 fps</td></tr><tr class="alt"><th scope="row">>3.5GB setting = 3840x2160 135% res</th><td align="right">19fps (-47%)</td><td align="right">15fps (-50%)</td></tr><tr><th scope="row">Call of Duty: Advanced Warfare</th><td align="right"></td><td align="right"></td></tr><tr class="alt"><th scope="row"><3.5GB setting = 3840x2160 FSMAA T2x, Supersampling off</th><td align="right">82 fps</td><td align="right">71 fps</td></tr><tr class="alt"><th scope="row"><3.5GB setting = >3.5GB setting = 3840x2160 FSMAA T2x, Supersampling on</th><td align="right">48fps (-41%)</td><td align="right">40fps (-44%)</td></tr></table></div>
Here's an example of some performance data:
On GTX 980, Shadows of Mordor drops about 24% on GTX 980 and 25% on GTX 970, a 1% difference. On Battlefield 4, the drop is 47% on GTX 980 and 50% on GTX 970, a 3% difference. On CoD: AW, the drop is 41% on GTX 980 and 44% on GTX 970, a 3% difference. As you can see, there is very little change in the performance of the GTX 970 relative to GTX 980 on these games when it is using the 0.5GB segment.
92 Comments on NVIDIA Responds to GTX 970 Memory Allocation 'Bug' Controversy
They could have just „leaked” how to enable the last 0.5GB and enthusiast would all try it and argue and debate about it on every tech forums if it’s worth it or not because of the performance hit (which is about 2-3fps?)
There would be no drama now then.
The likelihood of any game needing more than 3.5GB for a single frame is pretty low for where most people game. Nvidia has to make some tradeoffs in their architecture to achieve their massive efficiency gains over Kepler, tying the processors addressing capabilities to SMs is one of those tradeoffs. If anything, I think it was a smart tradeoff, it's taken this long for people to even notice there was a compromise made at all.
I think at the end of the day people are going to say, well this is one hell of a card still for 95% of gamers out there, and the other 5% that want to squeeze every single performance percentage out of 4k and multimonitor setups are just gonna throw down cash on a GTX 980(s) or 290X(s).
its not fair to people that have bought 2 or more for high res and multiple monitors. what would really make everyone happy again is if they could magically make vram stack in sli.
CoD:AW can allocate 3.2GB of memory usage on a 980 at 1080p VHQ according to GameGPU. Testing at 1440p would have been more convincing provide they show a detail rundown. Not that they need to convince me but not being forth coming is whats got them here.
To think that I was actually waiting on a double framebuffer variant of the 970 to upgrade my 2gb 770 . The only reason I whant to upgrade is that I made the mistake of getting a 2gb card instead of 4gb one . The performance is enough for my needs , but the stuttering is not something I can live with . Some more in-depth tests would be nice , I know stuttering can be subjective , but there must be a way to test that aspect of the performance .
If this is indeed the result of this card's problem, then no amount of price cuts or rebates can make up for it and a recall SHOULD be made for cards showing this.
The card will already be 6+ months old by then too.
:D
Making this out to be no big deal is how you end up with this type of issue as a continued thing to deal with. Voicing issues and opinions is how you end up with better products that is great for everyone and drives things forward.
Just because you can Google doesn't mean you have any idea what you are talking about.
nvidia is probably laughing about it because it took them an hour to figure it out and forward a statement to tech sites that is so simple its hard for a 20 year professional to quickly figure out when they where expecting something much more complex.