Folding@Home Flickering LED lights in my home...only with FAH

[Vester]

When I run my computer with the Nvidia RTX 3080 and the Titan X Pascal, it uses about 850 Watts and the output of the Back-UPS Pro 1500 droops to 117 Volts. The problem is that my home's LED lights flicker when running FAH. When I run Einstein@Home, it uses about 800 Watts, and the voltage droops to 117 Volts. The difference is that Einstein@Home does not cause the light bulbs to flicker. I can only presume that there are load fluctuations at about 60 Hertz which feed back to the house's electrical system. Thoughts or observations? I am using two power supplies, a 1000 Watt and a 1250 Watt.

 

[supdood]

I'm not an electrician or electrical engineer, but there are two things I can think of. Based on my experience with having the wrong dimmer switch when I changed over to LEDs, I know that they are more sensitive to voltage and current fluctuations/drops than other common electrical items in the house. So you may be pulling the house voltage down to 117 volts and the LEDs are simply what is showing an effect. The other cause is what you've suggested: rapid fluctuations in the GPU draw that are affecting the voltage and current throughout the house.

I don't know whether or how this would affect larger appliances, etc., but even if it doesn't, that sure is annoying to have all of your lights flicker. Hopefully someone with more expertise or experience can chime in!

 

[Nick Name]

I have LEDs throughout the house and have never seen this, although usually I only run 100% at night when the overall load is low and the lights are out anyway. I wouldn't be able to tolerate any flickering.

I would try something simple and plug directly into the wall, bypassing the UPS. That will tell you if it's actually the computer or the UPS is doing something weird.

Are you using 2 power supplies in the same machine? If so I would try to rule out one or the other and get one large enough to handle the total load.

 

[Vester]

Thanks. I will bypass the Back-UPS Pro 1500 when I run FAH this afternoon. I currently run two power supplies (1000W and 1250W), and I have another 1000W power supply that I can use to replace each of the power supplies currently in use.

 

[Nick Name]

Anything new to report?

 

[Vester]

First, the flickering occurs when running FAH under certain conditions. The problem is related to input voltage. There is no voltage drop through the Back-UPS 1500 Pro. Changing power supplies did not affect the situation. When the computer load gets to 840-850 Watts AND the input voltage gets to 115-116, the lights will flicker. My home is remote and the electrical load on my provider's system has increased due to more homes added along the two miles of wiring to my home. Voltage at the outlet varies from 121 to 114 volts at various times of the day (even if I turn off my HVAC system).

I have mentioned before that I would like to put my computer on 240 Volts. It is time to get my brother, the electrician, to wire it for me. I have plenty of capacity in my breaker box because we have changed to a gas dryer and a gas water heater. We will add whole house surge protection at the same time.

I am now running Einstein@Home which only uses ~750 Watts.

 

[Nick Name]

Interesting. Just out of curiosity, you mentioned the LED bulbs flicker. Did you recently change from incandescent and did they flicker? Or you've been using LEDs before the flickering started?

 

[Vester]

I haven't had any incandescent bulbs since curly fluorescent bulbs became available.

My solution will be an additional dedicated circuit for my computer. There are four LED lamps on outlets in the living room, two in the sun room, three in other bedrooms, and one in the computer room. Many times the bulbs flicker before complete failure. In my experience, LEDs do not last as long as advertised. Here's some info about flickering LED bulbs.

 

[Nick Name]

I've been pretty happy with my LEDs overall. I've had a few fail prematurely but not nearly as many as the old curly fluorescents you mentioned. They might have been ok if they were left on (or off ) most of the time, but they failed much quicker than advertised where they were frequently on and off during the day. The bathrooms were the worst. My only complaint is if the bulbs fail in certain fixtures, like the shop lights in my garage and the kitchen light, you have to replace the entire fixture. I think the kitchen light is 3 years old now or will be soon, I've already made my money back in savings over replacing the old circular fluorescents 2x a year. I have occasionally noticed a diode or two not coming on, but I haven't seen that for awhile.

 

[Vester]

I have made an interesting observation while running Einstein@Home on my ONE computer. I know that Microsoft wants to be a part of the green movement by suggesting that computers sleep, not use screensavers, etc. When I run E@H on Windows, I do not get as many PPD, and the computer uses about 650 Watts. When running E@H on Pop!_OS 22.04 LTS (GNOME 42.5), the computer uses ~850 Watts. The extra 200 Watts are worth the extra 25% (estimated) PPD.

 

[Nick Name]

Linux has been more productive than Windows since the release of Windows 7, or at least that's what I've read. XP was on par. 7 and later has a lot of overhead, I cannot recall the name right now but it was an effort to prevent systems locking up because of a video driver crash. Most of the time now if the driver crashes the computer will keep running without the BSOD. The downside of this for crunching is that processing is greatly slowed. The terms are escaping me right now but when 10 was released I believe there was some talk about a driver mode without this feature but to my knowledge nothing was ever released.

Just out of curiosity, do you know if some sort of power limit or clock speed limit is operating in Windows and not Linux? It wouldn't be surprising for Linux to use more but 200 watts seems like a lot.

 

[Nick Name]

The term I was failing at recalling is WDDM or Windows Display Driver Model. It was first introduced in Vista, not 7. Vista was a forgettable OS and that's why I thought it first appeared in 7...that's my story that I'm sticking to anyway.

 

[Vester]

Just out of curiosity, do you know if some sort of power limit or clock speed limit is operating in Windows and not Linux? It wouldn't be surprising for Linux to use more but 200 watts seems like a lot.

The answer is complex. After I quit using GreenWithEnvy to run the GPU cooler and to overclock 200MHz, (I now allow the VBIOS to control fans speed without overclocking), I saved about 40W on Linux. That means Linux is using about 160W more than Windows 11 Pro. Windows uses Visual Studio, and VS uses SSE computations whereas Linux uses FPU. FPU computations load the CPU more heavily resulting in more power consumption. From page 6 of the 13 page article How to Stress-Test CPUs and PCs (Like We Do):

Regardless of whether you're talking about CPUs or graphics cards, the general principle remains the same: however much energy is put in reemerges as waste heat.

To that end, we start by observing the CPU's power consumption via its package. Differences between various architectures and models can be massive. But our Core i7-8700 does a fairly good job of representing the upper-mid-range, given its 65W TDP.

Prime95 with AVX and Small FFTs takes first place in our comparison of stress tests, followed by powerMAX with AVX and AIDA64’s FPU test.

See the article's tables and note the power differences for Aida FPU and PowerMax SSE. Since power differences also exist for my two GPUs, the motherboard and the RAM, it is reasonable that my computer uses 160W more power when running Linux compared to running Windows.