mfaktc: a CUDA program for Mersenne prefactoring

[kriesel]

Originally Posted by James Heinrich

Buy It Now prices are useful, ongoing auction prices are mostly irrelevant. Most useful is the price of recently sold items, a version of which I use to update the price listing on my site.

As a possible shopper, I find ongoing auction prices and bid counts interesting, particularly on the nearly expired auctions, in the sense I might want to jump in on one that's appealingly priced below the lowest buy it now price of a reputable seller. Those that have 5 days to run yet, not so much.
Looking at the first page of of recently sold (thanks for the link), I saw a range $1309-1925, and auctions seemed to dominate the low end, buy it now the high end. (Note that $1309 was a preorder and wait, not actual product in hand.)

[kladner]

I am necessarily out of the TF business for a while. In the course of getting a cooler swap working, I realized that one fan on the GTX 1060 was stuttering and not running up to speed. After I pulled it, I found that the GTX 460 was running at about half of its previous outrageous output. Moving it to the primary PCIe slot did not help.

Consequently, I have a lot fewer power cables cluttering things up. Half speed on the 460 was not worth the power draw. I am now drawing just less than 200 W at the wall, with P95 LL at 4400 MHz. About 80 W idle. No pesky GPUs to fuss over. CPU Package power about 110-115 W.

The only way now is to see if I can get a 580 or the 570 running. Maybe there was something special about running the 460 in the secondary slot, with a card in the primary PCIe.

I have ditched all my TF work of any description. With cooler weather and no GPUs, at least I can look forward to a power bill drop.

[TheJudger]

Just uploaded a new set of binaries of mfaktc 0.21 for Windows using CUDA 10.0.

• mfaktc-0.21.win.cuda100.zip
• mfaktc-0.21.win.cuda100.extra-versions.zip

If you're already running mfaktc 0.21 using an older CUDA version there is no need to upgrade, the source of mfaktc are unmodified.
These CUDA 10.0 binaries are compiled for compute_30 (Kepler), compute_35 (Kepler Update), compute_50 (Maxwell), compute_60 (Pascal), compute_70 (Volta) and compute_75 (Turing).
No support for compute_20 (Fermi) or even older cards and only 64bit binaries - main purpose of these binaries are Volta and Turing GPUs. For the latter there are only 64bit drivers available so the decission was easy.

Happy factor hunting!
Oliver

P.S. I had no access to Volta and Turing running Windows - if someone has such a GPU running on Windows please run the full selftest (e.g. mfaktc*.exe -st) for all 4 binaries and report results. Thank you!

[petrw1]

I'll have such a beast in a few days.

In the meantime can I get a quick answer to:

"Is MFAKTC capable of stopping/pausing if my PC has to revert to a UPS during a power failure?"

I'll check the config parms when I get home.
I'm not sure it makes sense to have a UPS if the GPU will drain it in a couple minutes.

[James Heinrich]

Assuming your UPS has management software that can trigger events then it's trivial, even if your software of choice doesn't have power detection capabilities. In my case if the power it out for more than 5 seconds I get it to automatically run

taskkill /IM mfaktc.exe

[storm5510]

Originally Posted by petrw1

...I'm not sure it makes sense to have a UPS if the GPU will drain it in a couple minutes.

Or nothing, in my case. I have an APC. It's too small to handle this 1080 setup even when the AC is on. It sounds its alarm. No GPU usage, it is fine.

My solution was power taps plugged into the non-battery backed receptacles. It still provides the suppression, but no battery.

To reply to your comment: I do not think it is practical either.

[kriesel]

Originally Posted by storm5510

Or nothing, in my case. I have an APC. It's too small to handle this 1080 setup even when the AC is on. It sounds its alarm. No GPU usage, it is fine.

My solution was power taps plugged into the non-battery backed receptacles. It still provides the suppression, but no battery.

To reply to your comment: I do not think it is practical either.

A UPS sized to give even a few minutes of runtime on battery for a system with two ~240W GPUs and a couple of multicore cpus fully loaded is >1.5KVA in my experience. That is, 1.5KVA didn't do it; mains drop, UPS inverter overload-faults immediately. A total of 300W of GPU plus 12 cpu cores though, is ok. It will ride out the occasional lights-blinked or brief squirrel-short but not a sustained outage due to runtime limits. A 1.5KVA UPS is typically the top of the consumer/small office offerings readily available in local retail. A 2KVA UPS costs a LOT more than a 1.5.

[James Heinrich]

I have the CyberPower CP1500PFCLD, and I'm very pleased with it. Rated at 1500VA / 900W, which should be fine for most setups. Fully loaded you only have a few minutes of runtime, but as noted above if the outage lasts more than a few seconds I kill mfaktc and Prime95 and the runtime jumps to 15+ mins.

One gotcha that caught me when I was shopping for a UPS was that cheaper UPS's give a poor approximation of 120V sine wave, and that doesn't play nice with Active-PFC power supplies, as in the computer would shut down immediately upon switching to UPS battery. Switching to the slightly more expensive "pure sine wave" version solves the problem.

[kriesel]

Originally Posted by James Heinrich

I have the CyberPower CP1500PFCLD, and I'm very pleased with it. Rated at 1500VA / 900W, which should be fine for most setups. Fully loaded you only have a few minutes of runtime, but as noted above if the outage lasts more than a few seconds I kill mfaktc and Prime95 and the runtime jumps to 15+ mins.

One gotcha that caught me when I was shopping for a UPS was that cheaper UPS's give a poor approximation of 120V sine wave, and that doesn't play nice with Active-PFC power supplies, as in the computer would shut down immediately upon switching to UPS battery. Switching to the slightly more expensive "pure sine wave" version solves the problem.

That seems a very nice unit, but would probably not handle my Lenovo D20 load, which is directly connected to the AC outlet. I recently tried adding a lowly Quadro 2000 as third gpu. It was fine at idle, but caused the system to shut down promptly when a gpu app loaded the ~60W Quadro, so I conclude it was running near max PS load without the Quadro. It has a 1060W active PFC power supply. I assume that is rated output, so required input from the UPS would be higher than a KW. I vaguely recall checking it with a KillaWatt a while ago and concluding it exceeded the wattage rating of my largest UPS (1500/980). An HP Z600 has a 650W supply, which handles less gpu wattage but is ok on my UPSes.

[Mark Rose]

Originally Posted by kriesel

That seems a very nice unit, but would probably not handle my Lenovo D20 load, which is directly connected to the AC outlet. I recently tried adding a lowly Quadro 2000 as third gpu. It was fine at idle, but caused the system to shut down promptly when a gpu app loaded the ~60W Quadro, so I conclude it was running near max PS load without the Quadro. It has a 1060W active PFC power supply. I assume that is rated output, so required input from the UPS would be higher than a KW. I vaguely recall checking it with a KillaWatt a while ago and concluding it exceeded the wattage rating of my largest UPS (1500/980). An HP Z600 has a 650W supply, which handles less gpu wattage but is ok on my UPSes.

That's a bronze rated power supply, so you're looking around 82 to 85% efficient. Assuming 82%, and the 980 watt limit of the UPS, that means the internal draw can be no more than 800 watts without it tripping.

Unless your electricity is super cheap, a Gold or Platinum power supply would pay for itself quickly.

[kriesel]

Originally Posted by Mark Rose

That's a bronze rated power supply, so you're looking around 82 to 85% efficient. Assuming 82%, and the 980 watt limit of the UPS, that means the internal draw can be no more than 800 watts without it tripping.

Unless your electricity is super cheap, a Gold or Platinum power supply would pay for itself quickly.

What's up with the advertised Platinum 80+ power supplies? Others are indicated as 94%.

The HP Z600s are bronze 80+ also, but are oddly shaped so replacement with a more energy efficient type could be a challenge. https://www.ebay.com/itm/HP-z600-Workstation-650W-Power-Supply-508548-001/161652055904?hash=item25a3369f60:rk:1:pf:0
They're also limited by having only a single 6-pin gpu power cable.

For the Lenovo I'd be tempted to go for a slightly higher total output, to enable the third gpu.
Electricity is about to become effectively less costly, with the beginning of the heating season. Residential rates are around US$0.12/KW-HR here, so a KW base load is around $1050/year. Natural gas or cut-your-own wood is a much more economical heat source, but does no computing.