A posting on another forum stated that some of the earlier Nvidia drivers are faster than later ones, though I don't have link to that post (probably on Einstein). So I tried it out on my GTX 970 on GPUGrid, going back from 361.43 (the first of the CUDA 8 drivers) to 359.06 (the last of the CUDA 7.5 drivers). I tried to find the most comparable work units, but the trend is clear whether you get an exact match or not (Win7 64-bit in all cases):

361.43 (CUDA 8) driver:
e7s29_e2s13p0f526-GERARD_CXCL12VOLK_12998741_2-0-1-RND3569_1
13.85 hours (44% CPU utilization)

359.06 (CUDA 7.5) driver:
e12s19_e7s8p0f14-GERARD_CXCL12VOLK_12998741_1-0-1-RND7922_0
12.59 hours (31% CPU utilization)

The conclusion is that the older drivers produce both faster results and lower CPU utilization. (This card is supported by a full core of an i5-3550, so the numbers will be somewhat different on virtual cores.)

While I was at it, I compared the efficiency (work units/day/watt) of the GTX 970 to a GTX 960. Somewhat to my surprise, they are virtually the same, with the GTX 960 squeaking out maybe a 2 or 3 percent gain, but almost too small to measure reliably.

Very interesting. What about the "CUDA 8" drivers that are newer, perhaps more mature?
How about even older drivers. Any ideas on those vs. 7.5?

Good questions, but my experience is that the CUDA drivers are pretty stable once they are released, and the later driver versions just optimize gaming performance. I don't do games, and this is on a dedicated machine anyway, so that does not matter.

You are more than welcome to try it also, and post back.

By the way, I measured power using the TDP% in GPU-Z, and the CPU% in BoincTasks.

Same here:

362.00
41203 s for 280,650 credit WUs (6 samples)

359.06
38818 s for 280,650 credit WUs (3 samples)

MrS

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This has been seen before here.
Drivers become bloated with patches and it slows some apps down. Operating systems get bloated in a similar way. Basically each fix introduces an additional subroutine or set of subroutines.
The difference observed by Jim1348 was 10% while the difference observed by ETA was 6%, so perhaps subsequent drivers (ETA's being slightly newer) or different setups change things.

The latest apps hear are CUDA 6.5 so any drivers that support 6.5 should suffice (unless there has been reported issues).
To test any differences you do need a steady supply of the same work type, and to stick to the same setup.

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Drivers become bloated with patches and it slows some apps down. Operating systems get bloated in a similar way.

But the point here is that going from the last CUDA 7.5 driver to the first CUDA 8 shows that the difference is due mainly to the difference in the CUDA versions. That may be called "bloat", as there may be some additional overhead in CUDA 8 that is not needed, but otherwise your statement is rather general and not supported by any data or references to this effect.

The measurements that ETA got I expect are mainly due to the fact that he averaged over a larger number of work unit types. It would be nice to do only direct comparisons, but that may not be practical for a large number of WU's. But again, if someone wants to compare later (or earlier) drivers, that would be helpful too, as long as they state their methodology.

Same here: 362.00
41203 s for 280,650 credit WUs (6 samples)

359.06
38818 s for 280,650 credit WUs (3 samples) MrS

The difference observed by Jim1348 was 10% while the difference observed by ETA was 2%, so perhaps subsequent drivers (ETA's being slightly newer) or different setups change things.

The latest apps hear are CUDA 6.5 so any drivers that support 6.5 should suffice (unless there has been reported issues).

Doesn't 41203/38818=1.06144 Or a bit over 6% ?

Yes, thanks, should have said 362 took 6% longer & it does look like CUDA 8 drivers are slower at running CUDA 6.5 apps than CUDA 7.5 drivers.
Maybe I'm wrong but I presumed CUDA 8 was developed for Pascal and then patched for backward compatibility with earlier CUDA versions? Whatever the route I don't see why NV would dev for older products, so I would not expect any performance gain from CUDA 8 for 28nm GTX cards, though they might improve upon their earliest CUDA 8 drivers somewhat. As usual I suggest people stick to the CUDA 7.5 drivers they have unless they need new drivers or want to test and report on them - which is useful if it confirms CUDA 7.5 drivers are faster than CUDA 8 for GTX 900 series GPU's or any changes to the 6% to 10% performance drop.

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Whatever the route I don't see why NV would dev for older products, so I would not expect any performance gain from CUDA 8 for 28nm GTX cards

It would amount to customer loyalty, which unfortunately does not seem to be the current business model for NVidia and many other corporations.

Jim, thanks for this heads up. Switching to the 359.06 drivers has allowed one of my machines to make the 24 hour deadline for 7 of the last 11 WUs (sometimes by as little as 2.5 minutes). Previously it was missing all the 50% bonus times after "upgrading" to 362 drivers. I'm currently not having warm fuzzy feelings about nvidia.

Switching to the 359.06 drivers has allowed one of my machines to make the 24 hour deadline for 7 of the last 11 WUs (sometimes by as little as 2.5 minutes). Previously it was missing all the 50% bonus times after "upgrading" to 362 drivers. I'm currently not having warm fuzzy feelings about nvidia.

could you please let us know which GPU and which OS you talk about in this case?

I am asking because I seem to be in a very similar situation with one my PCs.
Thanks in advance.

Jim, thanks for this heads up. Switching to the 359.06 drivers has allowed one of my machines to make the 24 hour deadline for 7 of the last 11 WUs (sometimes by as little as 2.5 minutes). Previously it was missing all the 50% bonus times after "upgrading" to 362 drivers. I'm currently not having warm fuzzy feelings about nvidia.

You are welcome, and it surprised me a bit too. It was all due to someone on another forum though who noticed it first. I don't recall a comparable case for CUDA, though it used to happen all the time for the AMD OpenCl drivers.

Switching to the 359.06 drivers has allowed one of my machines to make the 24 hour deadline for 7 of the last 11 WUs (sometimes by as little as 2.5 minutes). Previously it was missing all the 50% bonus times after "upgrading" to 362 drivers. I'm currently not having warm fuzzy feelings about nvidia.

could you please let us know which GPU and which OS you talk about in this case?

I am asking because I seem to be in a very similar situation with one my PCs.
Thanks in advance.

Windows 7 and NV 750Ti factory super-clocked. It's only really working on 1 of my machines, the others are crunching just a bit slower so they don't quite make the 50% bonus. I suspect this is going to be short lived as WU sizes keep increasing even though GPUs have remained the same for quite a while. In my case upload time is also a factor as file sizes have increased. I've been looking at skgiven's Linux thread, a switch to Linux should yield about an 11% boost AFAIK.

Maybe you should ALL think about contribution rather than speed and "beggar thy neighbour"

As luck would have it, my GTX 970 machine crashed yesterday for no good reason and would not boot at all. The SSD (a Samsung 850 EVO) even disappeared until I re-enabled it in the BIOS. But after completely wiping it out with a secure erase, it appeared to be OK. Rather than re-installing Win7 64-bit, I decided to go with Ubuntu 16.04; the second of my machines to be converted.

The first GPU work unit was a GERARD_CXCL12VOLKX. That may not be exactly comparable to the one I did on Windows with the CUDA 7.5 driver, but at 11.2 hours, a 12% difference, it shows that things are heading in the right direction. I would not bother with that except for the crash, but it was a nice incentive.

Maybe you should ALL think about contribution rather than speed and "beggar thy neighbour"

I know what you want to say - but on this particular PC, crunching time is some 24,5 hours, on the average :-(
Win10 64-bit; GTX 750Ti; driver 365.19

Jim, thanks for this heads up. Switching to the 359.06 drivers has allowed one of my machines to make the 24 hour deadline for 7 of the last 11 WUs (sometimes by as little as 2.5 minutes). Previously it was missing all the 50% bonus times after "upgrading" to 362 drivers. I'm currently not having warm fuzzy feelings about nvidia.

You are welcome, and it surprised me a bit too. It was all due to someone on another forum though who noticed it first. I don't recall a comparable case for CUDA, though it used to happen all the time for the AMD OpenCl drivers.

The 6.12 app upgrade from 6.05 was similar, 5 1/2 years ago, and I recall successive driver 'updates' also slowed my GT240's down bit by bit.

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The 6.12 app upgrade from 6.05 was similar, 5 1/2 years ago, and I recall successive driver 'updates' also slowed my GT240's down bit by bit.

I have lost track of the world before Fermis.

By the way, the newer drivers may be better at OpenCl, at least on Folding. It is hard to get a direct comparison on my two GTX 980s, since I don't keep records and have to depend on the two cards getting the same type of work unit at the same time, which doesn't happen all that often. And if it is true on Folding, it may not be true on other OpenCl projects such as POEM; there is not as much consistency between projects as there is on CUDA that I have found. I think everyone would have to do their own tests to be sure.