1) Message boards : News : GPUGRID statistics graphs (Message 38760)
Posted 1 day ago by Profile skgiven
Key

Compute Capability (CC), GTX series-Scientist, GPU codename, [Maxwell models]

CC5.2 GTX900-Maxwell (GM204) [GTX980, GTX970]...
CC5.0 GTX700-Maxwell (GM107) [GTX750, GTX750Ti]
CC3.5 GTX700-Kepler (GK110)
CC3.0 GTX600&700-Kepler (GK104, GK106, GK107, GK208)
CC2.1 GTX400&500-Fermi (GF104, GF106, GF108, GF114, GF116, GF118)
CC2.0 GTX400&500-Fermi (GF100, GF110)
CC1.3 GTX200 (GT200)

I've not included non-GTX series cards or laptop GPU's because I'm lazy too.
2) Message boards : News : New publication: Our study of a disordered protein and its significance (Message 38758)
Posted 1 day ago by Profile skgiven
Substantive work. Your solid comparison to the NMR model is critical to further establishing and defining in Silico modelling as an acceptable if not superior alternative to the often more expensive, more invasive, more limited and less safe in vitro and in vivo research methodologies.
3) Message boards : News : GPUGRID statistics graphs (Message 38753)
Posted 1 day ago by Profile skgiven
The graphs show 7 generations of compute capability but the key shows 3.
Wishful thinking!
4) Message boards : Graphics cards (GPUs) : New Windows Nvidia driver released: 344.48 (Message 38707)
Posted 4 days ago by Profile skgiven
The changes are likely to only effect GTX 900 series GPU's.
5) Message boards : Graphics cards (GPUs) : Maxwell now (Message 38706)
Posted 4 days ago by Profile skgiven
I have not tried EVGA precision (yet) but I did eventually work out how to increase GDDR5 past 3505MHz using NV Inspector.

You have to set the P-states when they are not in use!
Presently working at 3605MHz...
6) Message boards : Graphics cards (GPUs) : Maxwell now (Message 38677)
Posted 5 days ago by Profile skgiven
The improvement was only 2 or 3% for me with the GPU at around 1406MHz.
There is a new compression algorithm which presumably runs on the GPU so any increase in GPU rate also increases compression rate. Anyway it appears there isn't a lot to be gained from increasing the GDDR frequency. That said, I just had a quick look at one GPU clock setting on one system and it's not like I actually overclocked the memory; just forced it to work at 3500MHz (as far as I can tell). It might be the case that at higher GPU clocks a memory frequency increase would result in greater performance, or that increasing the memory (as opposed to the GPU) allows you to run more efficiently (or not).
7) Message boards : Graphics cards (GPUs) : Maxwell now (Message 38629)
Posted 8 days ago by Profile skgiven
Thanks skgiven. Do you see an increase in performance on GPUGrid WUs when the memory clock is increased to 3500 MHz?

I think so but I don't have much to go on so far. I was really just looking for a MCL drop, which I found (~53% to ~45%).
To confirm actual runtime improvement (if any) that results solely from the memory freq. increase I would really need to run several long same type WU's at 3505MHz, then several at 3005MHz, all with the same GPU clock and Boinc settings. Ideally others would do the same to confirm findings.
That will take two or three days as there are a mixture of Long task types and each take 5 or 6h to run...
I think you would be less likely to spot a small performance change from running short WU's as those only have a MCL of around about 27%; it's not like we are overclocking here, just making sure the GDDR5 runs at the speed it's supposed to. Most of us run the Long WU's anyway, so that's what we should focus on.
8) Message boards : Graphics cards (GPUs) : Maxwell now (Message 38604)
Posted 9 days ago by Profile skgiven
Using NVIDIA Inspector you can make sure the Current GDDR5 clocks are high, but you have to match the P-State value on the Overclocking panel to the state shown on the left. For me the P-State is P2, so in order to ensure 3505MHz is used I have to set the overclocking Performance Level to P2. Then I can push the Memory CLock Offset to 3505MHz.
When I did this with the GPU clock at 1406MHz-ish, the MCU load dropped to 45%
While I can select to unlock the clocks I cannot increase past 3505MHz - it just reverts. Hopefully this will allow for better performance and tuning...

For those with this issue, you might want to create a batch file setting your required (command line) values, and getting it to run at startup or by create a clocks shortcut from NVIDIA Inspector and either just double-clicking on it every time you restart or get it to automatically run at startup.
9) Message boards : Graphics cards (GPUs) : Maxwell now (Message 38584)
Posted 10 days ago by Profile skgiven
Is 53% MCL really a bottleneck?

That's the question I started out trying to find the answer to - is the increased MCL really a bottleneck?
Our point of reference is that we know it was with some Kepler's. While that picture was complicated by cache variations the GTX650TiBoost allowed us to determine that cache wasn't the only bottleneck and the MCL was definitely a bottleneck in itself (for some other cards).

Shouldn't this bottleneck lower the GPU usage?

Depends on how GPU usage is being measured, but MCL should rise with GPU usage, as more bandwidth is required to support the GPU, and it appeared to do just that:
When I reduced CPU usage from 100% to 55% the GPU usage rose from 89% to 93% and the MCL increased from ~46% to 49%.
At 100% CPU usage both the GPU usage and MCL were also more erratic.

Also, when I increased the GPU clock the MCL increased:
1126MHz GPU - 45% MCL
1266MHz GPU - 49% MCL
1406MHz GPU - 53% MCL

So the signs are there.

Being able to OC or boost the GDDR5 should offset the increase in MCL (it did with Kepler's).

Did you try to lower the memory clock to measure the effect of this 'bottleneck'?

I tried but I cant change the memory clock - the Current Clock remains at 3005MHz (the default clock). It appears that NVidia Inspector, GPUZ (and previously MSI Afterburner) recognised that I've asked that the GDDR5 clocks are increased, but they don't actually rise.

I've tried Furmark, and it seems to be limited by memory bandwith, while GPUGrid seems to be limited by GPU speed:

I'm wondering if the measured MCL is actually measuring usage of the new compression system and if this actually reflects a bottleneck or not. Increasing the GDDR5 would be the simple test, but that's a non-starter, which is another question in itself.

The only way to confirm if the MCL increase is really a bottleneck is to run similar WU's at different GPU frequencies and plot the results looking for diminishing returns. You would still expect to gain plenty from a GPU OC, but should see less gain as a result of MCL increases at higher GPU frequencies. Even with a frequency difference of 1406 vs 1126 (280MHz) the MCL difference is just 18% (53% vs 45% load), but six or seven points down to around 1051MHz might be enough to spot the effect of a MCL bottleneck, if it exists.
10) Message boards : Graphics cards (GPUs) : Maxwell now (Message 38581)
Posted 10 days ago by Profile skgiven
It's a Palit NE5X970014G2-2041F (1569) GM204-A Rev A1 with a default core clock of 1051MHz.
It uses an exhaust fan (blower), so while it's a Palit shell it's basically of reference design. Don't know of any board alterations from reference designs.
My understanding is that Palit support GDDR5 from Elpida, Hynix and Samsung. This model has the Samsung GDDR5 and like other Palit models is supposed to operate at 3505MHz (7000MHz effectively). However it seems fixed at 3005MHz. While I can set the clock to 3555MHz the current clock remains at 3005MHz. Raising or lowering it does not change the MCL (so it appears that my settings are being ignored).
So while it can run at ~110% power @ 1.212V (1406MHz) @64C Fan@75% I cannot reduce the MCL bottleneck (53% @1406MHz) which I would prefer to do.

http://www.palit.biz/palit/vgapro.php?id=2406
PN : NE5X970014G2-2041F
Memory : 4096MB / 256bit
DRAM Type : GDDR5
Clock : 1051MHz (Base) / 1178MHz (Boost)
Memory Clock : 3500 MHz (DDR 7000 MHz)
mHDMI / DVI / DisplayPort

biodoc, thanks for letting us know you are experiencing the same GDDR5 issue. Anyone else seeing this (or not)?


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