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970's having performance issues using 4GB Vram - Nvidia investigating

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ALXAndy said:
http://www.pcper.com/news/Graphics-Cards/NVIDIA-Responds-GTX-970-35GB-Memory-Issue

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.

There. What they haven't said, however, is what happens when you actually go over 3.5gb and try and use the last 500mb.
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Thanks for that. Interesting.
 
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.
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My opinion:

So basically what that means is that the first 3.5GB probably has access to the full resources of the card and that the last 0.5GB which is segmented from the 3.5GB only has access to a limited amount of resources which would explain the performance drop > 3.5GB because the last 0.5GB has significantly less bandwidth than the rest of the RAM. Essentially what they are saying is that the 970 only really can handle 3.5GB at full performance because of the SM/Crossbar setup differences between the 970 and 980.
 
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So removing SMMs to make the GTX 970 a lower spec product over the GTX 980 is the main issue here, 500MB is 1/8t of the 4GB total memory capacity yeah, two SMMs is 1/8th of the total SMM count. So the answer really is, the primary usable memory for the GTX 970 is a 3.5 GB partition.
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From Guru3D, makes sense
 
Stas823 said:
Ofcourse why would they mislead us, its not like they are selling a hobbled product.
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They have told no lies have they.:)

Also when you say hobbled product from their point of view it could mean on the 9 series

256 bit bus
Using data compression
4gb of VRAM instead of more
Below par coolers on the reference cards
And the list goes on

The above sounds a lot worse than it really is but the bottom line is NVidia have built the 970 and 980 with a lot of compromises as these are not going to be the top of the range flagships. NVidia will see how the VRAM works on the 970 as yet another compromise.

Even despite this ongoing problem the GTX 970 is still a very good card with a lot of happy users, well worth recommending to everyone.:)
 
Andromeda1983 said:
From Guru3D, makes sense
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That's not the whole issue.

Both the GTX980 and 970 have 4 raster engines, each with 4 SMM units. On the 970 3 of the 16 SMM units are disabled, the issue arises if all 3 disabled SMM units are from the same raster engine rather than one from each of the first three; which people are speculating is the case.

Kaapstad said:
They have told no lies have they.:)

Also when you say hobbled product from their point of view it could mean on the 9 series

256 bit bus


The above sounds a lot worse than it really is but the bottom line is NVidia have built the 970 and 980 with a lot of compromises as these are not going to be the top of the range flagships. NVidia will see how the VRAM works on the 970 as yet another compromise.

Even despite this ongoing problem the GTX 970 is still a very good card with a lot of happy users, well worth recommending to everyone.:)
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The way the 970 is cut down appears to effectively lower the memory bus below the 256bit required for 4gb of vram, to around 208bit
 
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Swagger187 said:
Never been the most patient person in the world. What the hell are Nvidia going to do about this I wonder.
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They can't recall. They simply can't. It wouldn't bankrupt them by any means, they could certainly afford it... but it would a massive admission of guilt, their share price would tank and they'd send every potential new customer running in to the open arms of AMD. You'd be seeing it on the 10 o'clock news, and they won't let that happen. So... they'll either fix it via firmware update, or lock their team of overpaid lawyers in a room working overtime with their smartest tech minds until they come up with a way out that basically screws us all but protects them. The fact most of us won't ever buy Nvidia again won't matter much, as ultimately this is the best case scenario for them if there's no fix.
 
ReCoN1989 said:
That's not the whole issue.

Both the GTX980 and 970 have 4 raster engines, each with 4 SMM units. On the 970 3 of the 16 SMM units are disabled, the issue arises if all 3 disabled SMM units are from the same raster engine rather than one from each of the first three; which people are speculating is the case.
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This makes sense as the chips that don't get used on the 980s could have defective/disabled SMM units anywhere.
 
ReCoN1989 said:
That's not the whole issue.

Both the GTX980 and 970 have 4 raster engines, each with 4 SMM units. On the 970 3 of the 16 SMM units are disabled, the issue arises if all 3 disabled SMM units are from the same raster engine rather than one from each of the first three; which people are speculating is the case.



The way the 970 is cut down appears to effectively lower the memory bus below the 256bit required for 4gb of vram, to around 208bit
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As I said above NVidia would see this as another compromise for the 9 series.

The 256bit bus is there, it is just not working the way it should which is not good.
 
Legend said:
I am on the verge of calling 'Nvidia plant' to anyone who takes this line of rhetoric... it's such a ridiculous thing to say, and TOTALLY beside the point.
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No

It is totally the point as we need to stick to the facts.

I would also like to remind you that I have been the biggest critic of the NVidia 9 series on these forums right back to launch day when I was in a minority of one.:)
 
Kaapstad said:
As I said above NVidia would see this as another compromise for the 9 series.

The 256bit bus is there, it is just not working the way it should which is not good.
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The problem is that it's not there. That is what's causing the problems! once vram usage goes above 3.5GB there is insufficient bandwidth in the memory bus causing rapid loss of throughput and stuttering. Which wouldn't occur if the full 256bit bus width was available.
 
" NVIDIA’s focus is on the performance ramifications – mainly, that there generally aren’t any..."

Yet from users feedback in games that are accessing that 0.5GB of RAM, they are reporting clear and obvious performance issues, so if true would make this statement totally false and basically a lie.
 
Legend said:
" NVIDIA’s focus is on the performance ramifications – mainly, that there generally aren’t any..."

Yet from users feedback in games that are accessing that 0.5GB of RAM, they are reporting clear and obvious performance issues, so if true would make this statement totally false and basically a lie.
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Or users could be trying to run a game/settings that needs more than 4gb which would make a 980 perform badly as well.

More testing needs to be done in a more scientific way than it has been done so far.
 
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