AVX512 hardware recommendations?

[ewmayer]

Originally Posted by preda

OpenCL is not initialized correctly. It hangs when doing some basic OpenCL like list all the devices of an opencl provider. There's not much to fix in gpuowl for this IMO, you should get clinfo to report a valid device first.

Been looking online for possibly useful info re. "No platform"|"No devices found in platform" errors for this family of GPUs, no luck so far. One thing that seemed possibly useful was to re-run clinfo with the -A flag:

-a, --all-props
try to retrieve all properties, even those not officially supported (e.g. because they require specific extensions), but
only show them if the property could be retrieved successfully; see also the LIMITATIONS section below; note that even
though this may reveal hidden properties, there is no guarantee that the returned values are meaningful, nor that the cor‐
responding feature is actually available at all;

-A, --always-all-props
like -a, but also show errors;

That gives one extra line of output vs just 'clinfo':

<gatherPlatformInfo:5: get CL_PLATFORM_MAX_KEYS_AMD : error -30>

But I don't know if that is useful except as another thing that indicates "your OpenCL install is borked on this system."

[kriesel]

Originally Posted by kriesel

It was so flaky in the early going I thought I would be returning it shortly.

Flakiness increased again, a lot Shortly arrived. So did the return ship label by email. So the NUC is
on the road again
https://www.youtube.com/watch?v=NCs8ufxnnYA

[ewmayer]

I realize we're talking about relative small potatoes here, but disappointingly, the new NUC8i3CYS is no more power-efficient than my older NUC5i3RYK unit, despite the newer chip, smaller process size, presence of avx-512, etc. The problem is not the CPU itself, but rather the voltage-converter brick - let's compare old (with its much-smaller V-converter) vs new. All wattages are at-wall-outlet:

Old: V-converter plugged in, NUC off, < 1W. NUC on, running 4-threaded Mlucas_v19_avx2, TPD = 18W.

New: V-converter plugged in, NUC off, 16W[!]. NUC on, running 4-threaded Mlucas_v19_avx512, TPD = 33W.

Thus each fully-loaded CPU (these are both 2-core, but I get best throughput running 2 threads per HT core) accounts for 17W, with the newer NUC's CPU getting ~1.8x the throughput for the same watts. But the V-converter parasitic load on the newer NUC sucks as many watts as the CPU itself. Annoying.

From the technical product specification for my older NUC (call it nuc1) I see this:

External Power Supply – the board can be powered through a 12-19 V DC connector on the back panel. The back panel DC connector is compatible with a 5.5 mm/OD (outer diameter) and 2.5 mm/ID (inner diameter) plug, where the inner contact is +12-19 (±10%) V DC and the shell is GND. The maximum current rating is 10 A.
NOTE
External power voltage, 12-19 V DC, is dependent on the type of power brick used.

And here for the newer NUC (call it nuc2):

External Power Supply – the board is powered through a 19 V DC connector on the back panel. The back panel DC connector is compatible with a 5.5 mm/OD (outer diameter) and 2.5 mm/ID (inner diameter) plug, where the inner contact is 19 (±10%) V DC and the shell is GND. The maximum current rating is 4.74 A.

Coax power plugs same, but nuc2 requires 19V, whereas nuc1 allows a range. Question is, what is the power supply for nuc1 rated at? The writing on its side is oh-so-tiny, but using a 20x magnifier I see: 19V / 3.43A / 65W max. That is enough to drive both NUCs, and with the 16W PSU-load from nuc2's stupid-design brick eliminated, should be enough to also do GIMPS works on nuc2's Radeon540 GPU, if I ever figure out why OpenCL under the Ubuntu 19.10 OS I installed on that NUC is borked (fails to see the GPU).

So a simple splitter like this hooked up to the older/smaller/more-efficient nuc1 brick should work, no?

[Xyzzy]

If you use the newer adapter it should work. It will stress the brick a bit more.

We just got a new NUC8i3BEK. Our older NUC from 2014 killed a memory stick and then the wifi card started acting up.

The new one is stupid fast compared to the old one.

https://ark.intel.com/content/www/us...s=83256,126149

[ewmayer]

Originally Posted by Xyzzy

If you use the newer adapter it should work. It will stress the brick a bit more.

By "newer adapter", you mean the splitter? Re. stress, that's why I checked the rating on the older, smaller brick - it would need me to also load up the GPU on nuc2 to get near the 65W rating, so hopefully the expected ~35W from the combined nuc1 and nuc2 CPU-only loads will be no problem.

We just got a new NUC8i3BEK. Our older NUC from 2014 killed a memory stick and then the wifi card started acting up.

The new one is stupid fast compared to the old one.

https://ark.intel.com/content/www/us...s=83256,126149

So you need to get an SSD memory stick and RAM on top of the basic unit? What amounts mem & ram did you get, and what was the total cost?

What OS are you using?
What SW are you running - on CPU, on GPU as well? - and how do timings compare to old-NUC?

[Xyzzy]

Originally Posted by ewmayer

By "newer adapter", you mean the splitter?

No, we mean the AC/DC adapter that has the higher watt rating.

Originally Posted by ewmayer

So you need to get an SSD memory stick and RAM on top of the basic unit? What amounts mem & ram did you get, and what was the total cost?

We had a spare 1TB NVME SSD and we bought ($150) 32GB of memory. It will (unofficially but very reliably) take up to 64GB but that was a bit more than we were willing to spend.

Originally Posted by ewmayer

What OS are you using?

Red Hat 8

Originally Posted by ewmayer

What SW are you running - on CPU, on GPU as well? - and how do timings compare to old-NUC?

This is an everyday computer so we aren't running any compute jobs on it. We think that maybe the reason our old NUC is dying is due to years of getting super hot. The new one has a much better cooling system but we don't feel like taking the chance given the CPU+iGPU output would be so small compared to a real GPU. (Fun fact: Our NUC has 128MB of dedicated graphics memory so in many benchmarks it is faster than the newest 10 series NUCs.)

[ewmayer]

Originally Posted by Xyzzy

No, we mean the AC/DC adapter that has the higher watt rating.

That would defeat the purpose, as the newer beefier PSU is the one that burns as much wattage just when plugged in as the CPU does fully loaded. That one will serve as a backup, in case the doubled load burns the old/small/nonparasitic PSU out.

Does your CPU model support avx-512? If so, seems a waste to let all that vector-math capability go unused.

Oh, under your flavor of Linux, does OpenCL see your GPU?

[Xyzzy]

Originally Posted by ewmayer

Does your CPU model support avx-512? If so, seems a waste to let all that vector-math capability go unused.

No. We think your model is the only one that has that.

[sdbardwick]

Ernst, I'd be more likely to believe that the new power adapter is spoofing the power meter rather than wasting 16W at idle. The quest for efficiency in wall-warts (and regular PSUs as well) leads to all sorts of weird input characteristics at low power outputs.

For example, at low loads some newer PSUs draw only near the +- peaks of the AC line; (less current for same power) and rely on capacitors to maintain output when not drawing from the AC line. This intermittent draw can fool power meters into misrepresenting the actual power consumption.

EDIT: Then again, maybe the seller replaced the Intel stock power adapter with a horribly inefficient generic replacement. Can you post a pic of the new power adapter's label?

[retina]

Originally Posted by sdbardwick

EDIT: Then again, maybe the seller replaced the Intel stock power adapter with a horribly inefficient generic replacement. Can you post a pic of the new power adapter's label?

Hold it in your hand. You can feel the watts from the heat. Warm == lots of watts. Cool == fewer watts. Compare to the older model.

Why are people always looking for a highly technical solution when a simple old school approach will be faster and easier?

[sdbardwick]

My power adapter from same model NUC bought new in 2019 (hi-res for easy reading)