NVIDIA Maxwell Speculation Thread

silent_guy

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It's not exactly static in the sense that the signal is either low or high, but as an approximation, I simply take VDDio and divide by half. So 0.7V. On the receiving side, you have 2 40 Ohm resistors in parallel (on to ground, one to lower), so you get 0.7^2/20 = 24mW per IO, or 9.5W for a 384 bit bus.

This is probably a terribly approximation, since it excludes series resistance etc, but it gives a ballpark number.

I think this is the most important reason why HBM saves power over conventional DRAMs.
 

silent_guy

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This is probably a terribly approximation, since it excludes series resistance etc, but it gives a ballpark number.

I think this is the most important reason why HBM saves power over conventional DRAMs.
I'm starting to think that I was very right about this being a terrible approximation, and that it's not anywhere close to being as high as I claimed it would be.
 

CarstenS

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Maybe this comes in handy?
hgvG3vq.png


Source: http://images.nvidia.com/events/sc15/SC5125-energy-efficient-architectures-exascale-systems.html
 

silent_guy

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silent_guy

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There is one strange behavior in that graph as well: compared to GDDR5, the column power consumption is actually higher even though the BW is lower.

That doesn't make a lot of sense...
 

3dilettante

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There is one strange behavior in that graph as well: compared to GDDR5, the column power consumption is actually higher even though the BW is lower.

Which ones have higher column power but have lower bandwidth?
The black line seems to be always increasing, and the green bar segment for column power seems to do so as well.

The on-die power costs seem to rise along with bandwidth, which one would expect since something needs to be read/written and higher bandwidth means more of it.
 

silent_guy

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Which ones have higher column power but have lower bandwidth?
The black line seems to be always increasing, and the green bar segment for column power seems to do so as well.

The on-die power costs seem to rise along with bandwidth, which one would expect since something needs to be read/written and higher bandwidth means more of it.
Oops, I misread the graph!

Still, while the HBM1 BW goes up marginally from the fastest GDDR5 number, the column power seems to increase higher than you'd expect given the lower core voltage.
 

3dilettante

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It's eyeballing a graph, but would the relative difference between the GDDR5 data point and the HBM one be in the range of 30-50%?
Perhaps the internal voltage isn't reduced as much?
The column power increase seems to be in that ballpark. There is a drop in row power between HBM and HBM2, which might be attributable to pseudo-channel mode cutting the page size per activation in half, given that the graph is assuming only 160 bytes per 1-2KB page activation gets used.
At least for graphics, this might be too conservative relative to what HPC might get.

Really changing the curve would require a significant change in the actual core arrays (or even the base storage tech?), which have been kept pretty consistent across all the interfaces in the comparison.
 
From Hardware Battle: "Nvidia preparing GTX980MX and GTX970MX" (original).

In terms of specifications, we are looking at the following inequalities:

GTX 970M (1280 CC, 192-bit) < GTX 970MX (1408 CC, 192-bit) < GTX 980M (1536 CC, 256-bit) < GTX 980MX (1664 CC, 256-bit) < GTX 980 [laptop] (2048 CC, 256-bit).

The report says that the 970MX and 980MX will arrive next quarter and replace the respective -M parts.
I revisited this rumor while looking for information related to a Pascal rumor, and Hardware Battle has issued an update sometime between the time of my quoted post and now.

The current situation is this rumor has been refuted. Haneungunyo japneundago the strands in the direction of Pascal quickly launch new products, not Maxwell.
 

Kaotik

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Is it possible to disable driver command lists support in Maxwell gen 2 cards somehow?
I'd just like proof on whether Hallock was full of it, or actually right, that DCLs help short benchmarks but actually hurt performance in the long run
 

Razor1

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Kaotik, not sure where you are going with that, command lists are done on the CPU, but even submitting a command list won't tell a GPU to start working, so I think in theory yeah there should be a way to disable it. But by doing so, you still need to have a completely new command list that will effectively visually look the same which I don't think would be easy to do, unless you know what the original command list is and this is pretty expensive on the CPU.

Ah yeah missed that statement in the AMA, damn Reddit lol.

Yeah what Hallock stated, doesn't sound likely, I don't know if nV has much control over the command lists to that degree, essentially what nV would have to do is know how the driver threading would predict the command lists and and what branches. I'm not sure if they have that much control over the application to do that. Any one else?
 
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NVIDIA Cuts Prices of GTX 980 Ti, GTX 980, and GTX 970

The price of the $620 GTX 980 Ti has been cut by $125, and is now down to $495~499. The GTX 980, on the other hand, sees its price cut by $75, bringing its price down from $399 to $324, less than the launch-price of the GTX 970. The smash-hit GTX 970, at the dusk of its market life, sees its price cut by $25, bringing it down from $289 to $265.
https://www.techpowerup.com/223432/nvidia-cuts-prices-of-gtx-980-ti-gtx-980-and-gtx-970
 

CSI PC

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June 15, 2016: Counterfeit "GeForce GTX 960" cards in USA & China surfaced
Before Geforce GTX 1060: Counterfeit GTX 960 at low prices in circulation

06.15.2016 at 16:45 some alleged Geforce GTX 960 offered at bargain sales prices on the sales platforms Ebay and Amazon Marketplace. before the introduction of the Geforce GTX 1060. Actually, however, it involves old Fermi models with a mod BIOS allowing GPU-Z reads the graphics card GTX 960. Bargain hunters should look carefully when buying
http://www.pcgameshardware.de/Nvidi...-960-zu-guenstigen-Preisen-im-Umlauf-1198678/
 

CSI PC

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From 320 to 150(390x to 480) Just wow...
Although the shock is how high the 390x is compared to the 290x, especially as it is was meant to have better dynamic power management.
The TBP for a 290x & 290 was 250W, and the Fury X 275W (so its real-world figure is pretty good in the measurements).

Cheers
 
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