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Question GPU's crunching vs central heating system

Assimilator1

Elite Member
Nov 4, 1999
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So I wondered at what point I'd be better off running my GPUs vs turning on my (gas) central heating for x hrs during the day when it's normally off (I'm furloughed atm, so at home during the day until the 30th).

I had my heating on for an hour (with it being about 9C outside) and it used 0.720 m3 of gas today, this site reckons that's 8.1811 kWh.
On my main rig, running 10T Rosetta and dual MW WUs on the GPU (@850 MHz) it's drawing ~227w, with 12T Rosetta only it's ~116w, so ~111w running the GPU. For 24 hrs running the GPU adds 2.664 kWh, quite a lot less energy than 1hrs heating! But even today just running my main rig's GPU wasn't quite enough to keep me warm, so I needed to find out what my 2nd rig draws too.

My electricity charges are 15.72p/kWh and 21p/day standing charge.
Gas is 3.25p/kWh, standing charge is also 21p/day (I need to shop around to see if that's still any good).
So for 24hrs GPU crunching on my main rig that's 41.5p, and 1hrs gas is 26.6p (+ standing charge for both).
If I've got that right, it would take just an extra 2hrs heating per day to exceed the cost of running 1 GPU all day! (at 9C outside anyway).

My 2nd rig uses ~110w idling! lol. Running MW on its GPU it's drawing ~228w (and CPU is otherwise mostly idle. When loaded IIRC it adds about 100w).
So running my 2nd rig 24hrs/day, GPU crunching only, would add 5.472 kWh a day x15.72 = 86p/day, costing slightly more than 3hrs of heating (79.8p, with 9C outdoors temp).
Going by that, if I ran my 2nd rig just 6hrs/day (21.5p) it would be cheaper than running my heating an extra hour (26.6p). Sounds like a good excuse to GPU crunch! :D (assuming 2 GPUs can keep me warm enough to prevent me from having to turn on the heating any extra).

Are my maths right?

Has anyone else worked it out (assuming your GPUs aren't producing more heat than you need! lol)
 
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Endgame124

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Feb 11, 2008
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Since I work from home (and have for the last 8 years), I found that in Nov and March I could turn the house heat down substantially and just let the computers in my office keep things warm enough in the office to be comfortable. Dec - Feb, though were too cold - I just didn't have enough computers to keep my office warm, so I had to supplement with additional heat.

I never worked out the actual costs, though - I just figured that heating one room with computers had to be more power efficient than heating the whole house that I wasn't using at the time.
 

Assimilator1

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Nov 4, 1999
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Ah yea, forgot to say, me and my gerbils are hold up in the lounge ;), so yea my PCs are only heating the lounge, mostly.
I suppose for using my heating I could turn off all the other radiators during the day, but that would be a PITA! :p
 
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Markfw

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Not that its the most efficient (its NOT), but my furnace has not been turned on in years. I have gas heat, but I choose to so medical research with all my rigs. What differs for me is how many windows are open, even with it 29f (freezing) outside. I almost got the house closed up when it got down to 28 one night.
 
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Assimilator1

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Interesting article! Although I won't go that far ;)
I also read 1 of the articles about the Ryzen 3950, another interesting article :).

Not that its the most efficient (its NOT), but my furnace has not been turned on in years. I have gas heat, but I choose to so medical research with all my rigs. What differs for me is how many windows are open, even with it 29f (freezing) outside. I almost got the house closed up when it got down to 28 one night.
Lol, crazy! :), can't you reclaim some of that heat, to say heat water? Some sort of heat exchanger on the cold water feed to the hot water system??
 
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Assimilator1

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Nov 4, 1999
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Yea I think I'd struggle to get the boiler to fold! ;)
Re gas prices, I don't know how it compares to other countries, but I know theirs been dwindling returns from the North sea oil/gas rigs over the past 10yrs or so, and so we've had to import more gas. Also I know the US has gotten into fracking a lot in a similar period (which I'd imagine has helped gas prices as well as oil prices?), fracking is very unpopular over here due to the problems it can cause. AFAIK, aside from test drilling's (which caused a lot of tremors not that far from me!), no fracking 'rigs'(?) have been setup.
How much is your gas?

Re electricity costs, I don't know tbh, IIRC about 1/4 ([edit] I'm out of date, now well over 1/3 heading for 1/2!:)[edit2] Seeing mixed reports, this shows a little over 1/4, still pretty decent, I think!) of our electricity is from renewable's (largely wind I think), maybe because of that?? Although we import some electricity from France which uses a lot of nuclear :p, I've no idea if that's cheap electricity or not though!
That also means less CO2 output if I heat with my GPU than use my heating! lol
Oh and if you like stats and graphs, check this out! :cool:

How much is your electricity?
 
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Endgame124

Senior member
Feb 11, 2008
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Yea I think I'd struggle to get the boiler to fold! ;)
Re gas prices, I don't know how it compares to other countries, but I know theirs been dwindling returns from the North sea oil/gas rigs over the past 10yrs or so, and so we've had to import more gas. Also I know the US has gotten into fracking a lot in a similar period (which I'd imagine has helped gas prices as well as oil prices?), fracking is very unpopular over here due to the problems it can cause. AFAIK, aside from test drilling's (which caused a lot of tremors not that far from me!), no fracking 'rigs'(?) have been setup.
How much is your gas?

Re electricity costs, I don't know tbh, IIRC about 1/4 ([edit] I'm out of date, now well over 1/3 heading for 1/2!:)[edit2] Seeing mixed reports, this shows a little over 1/4, still pretty decent, I think!) of our electricity is from renewable's (largely wind I think), maybe because of that?? Although we import some electricity from France which uses a lot of nuclear :p, I've no idea if that's cheap electricity or not though!
That also means less CO2 output if I heat with my GPU than use my heating! lol

How much is your electricity?
Electricity here just outside of Washington DC is 17.5 cents KW/h. I’m pretty sure Natural gas for heat is dramatically cheaper, but I don’t know the price off hand. I probably wouldn’t be doing DC at all if it weren’t for the fact I installed 9KW of solar panels
 

Endgame124

Senior member
Feb 11, 2008
435
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Nice! :)
When do you think they'll have paid themselves back?
Assuming every year is like 2020 for sunshine, Including the state solar energy credits, the saved electric on the bill, and the check I got last year for excess generation, 4 years, 8 months.

payoff would be longer, but I got the maximum federal and state tax credits, and an installation discount for a down payment not tied to a solar loan.
 

Endgame124

Senior member
Feb 11, 2008
435
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Not bad at all :)
Yeah, it’s why I want to put panels on the other half of the house. The west side of the house has room for 30 panels, though output will decrease slightly due to slight northern facing and a tree that casts afternoon shade. It looks like 340 watt panels are available now, so hopefully by the time I’m ready panels will be in the 350-360 watt range.

Unfortunately the federal credit reduced at the start of 2020 and goes away in 2021. I’m really hoping the new administration brings it back so I can keep the payoff time reasonable - otherwise payoff takes almost 7 years. Still worth it with a 7 year payoff, but not as nice.
 
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petrusbroder

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Nov 28, 2004
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Well, I have to add my 2 cents ... but this is history.
When living i Umeå, the major city in northern Sweden, just about 400km south of the arctic circle, we lived in a nice, well insulated, stone basement house with six teen agers and two adults ... In one room in the basement I hade 21 computers with 23 GPUs (this was 2008 - 2012), in the adjacent room two big freezers, one washer, one dryer, one water heater and one refrigerator (you need a lot of food to feed teenagers). I collected all the hot air from the computers with a big hood and a big "kitchen fan" and with a fan only from the adjacent room, piped the hot air to an heat exchanger in the attic (in well isolated air-pipes) which used the heat to heat incoming fresh air which was distributed through out the house. We also had heating based on geothermal heat. The geothermal heat was only used for 3- 4months a year and only when the out side temperature dropped below -10ºC (=14ºF). OTOH one winter we had a period of real cold (below -20ºC (=-4ºF) for 6 weeks, with a maximum low of -32ºC (=-25,9ºF)). Still, the electric bill dropped by more than 65% during comparable years after I've installed that system.
The power savings payed for the computers' power and fiber internet connection ...
21 crunchers, crunching 24/7, using approximately 250 - 300W each, that was a lot of heat. Originally I installed the fan system to keep the room cooler and then I had the idea of using the hot air. The heat exchanger I bought from Finland ... and all the piping I did myself with the help of a good friend and ventilation engineer, who later developed that idea and sold it.
The image below was 4 months before I installed the hood collecting all the hot air, you can see the big "kitchen fan" up left, this only shows some of the computers. 7 were below the work bench (right), and some more on the shelf to the left. The ethernet connectors up center was one of three in that room.

CompRoom-3.jpg
 

cellarnoise

Member
Mar 22, 2017
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This thread is great!

I saved the pic of the "power" room from Petrusbroder. That is such a mashup of puters! Love it.

I am planning on doing the same thing that my wife is now working in an upstairs bedroom. I am WAY too cheap to try and heat the whole house to keep her happy as she works through COVID at home. I think I might need to move a puter or 2 up to her space for this year! Love it!

Though I will likely need to sacrifice and build some new room hearter for my basement office :( !!!
 

Markfw

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Super Moderator
May 16, 2002
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Do any other TEAM members want me to refresh pics of my farm ? Its really kind of boing, and the puters are in my sig, but some may want to see.
 
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cellarnoise

Member
Mar 22, 2017
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Yes please, Mr Mark. Only cause I am new to this past two years and would like to see what modern heavy duty hardware looks like. Though I think most of it will be beyond my league.

Myself, I hope to do a new 16 to 32 core before March... We shall see what ships before March?
 

Markfw

CPU Moderator, VC&G Moderator, Elite Member
Super Moderator
May 16, 2002
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Yes please, Mr Mark. Only cause I am new to this past two years and would like to see what modern heavy duty hardware looks like. Though I think most of it will be beyond my league.

Myself, I hope to do a new 16 to 32 core before March... We shall see what ships before March?
Well this is about as exciting as it gets. First here is a dual 7601 EPYC....



OK, on the left is a 3950x 16 core. On the right is a 7742 with a 2060 Super video card


Here is (left to right) a 7B12 EPYC, a 2990wx and a 7452 EPYC



Here front to back is a 7742 EPYC with a 2080TI, as 2970wx with a 1070TI, a 7551 EPYC and a 2695 Xeon



I missed a few, but thats as exciting as it gets.

Edit, Boy these pics show dust I didn;t know I had.....

Also missing, a 2990wx, 3 3900x's, a 2983v3 Xeon and a 1950x. Too many pics to shoot, and those are boring compared to the rest.
 
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Assimilator1

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Nov 4, 1999
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Lol, yea bit dusty ;), hmm, I see my main rig isn't much better! :eek:
Nice set of rigs otherwise:cool:

So running my 2nd rig 24hrs/day, GPU crunching only, would add 5.52 kWh a day x15.72 = 86.8p/day, slightly more than 3hrs of heating (with 9C outdoors temp).
Btw I messed up my maths (or just typod) and no one noticed :p.
It turns out the site I 1st used slightly miscalculated the kWh, my 2nd rig running 24/7 uses 5.472 kWh not 5.52 (I'll correct the op in a minute).

I think I might need to move a puter or 2 up to her space for this year! Love it!
I think she's about to become a big DC fan! :D
 
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petrusbroder

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Nov 28, 2004
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Nice setup that was :cool:, I vaguely remembered you said you had geothermal heat, I'd forgotten the rest!
Re 6 teenagers, you must have had the food delivery trucks skip going to the supermarket and go straight to your house! lol :tearsofjoy:
Well, yes. Teenagers in Sweden are like calfs: they drink tremendous amounts of milk. We had a delivery each Thursday morning of some 18 liters milk, 10 liters yoghurt och some packages of cream, and such stuff and 7 boxes of margarine ... and paid half the price compared to the supermarket. A friend was a farmer and delivered each week fresh meat (beef, lamb and/or pork) and an other farmer potatoes ... we are talking in 20 kg sacks ... but it was really fun. We cooked good food, so the kids ate at home and brought their friends. at least 5 days a week we were about 10 - 11 persons around the dinner table and we knew where the kids were. Food is attractive when well cooked and prepared. OTOH: it took some planning, preparation and time - but it was worth every effort. The kids knew where they would find food, people who would listen and talk to them and they knew the rules and - much to our surprise - learned to follow them. And, as one son told me recently - he is now 29 years old - he remembers the time very fondly, especially when ... <OK, I won't tell> ;-)
 

Assimilator1

Elite Member
Nov 4, 1999
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Turns out that the power usage of ~227w for my 2nd rig with the HD 7870XT DS is with it underclocked at 850 MHz. It's supposed to be 925 MHz but theirs some sort of bug with the drivers that sets the wrong speed, and the latest driver revision compounded that by breaking the manual setting of GPU clock, so it's stuck at 850 MHz (same with MSI afterburner).
However, sometimes the driver crashes and when it reloads then the proper setting takes effect! I notice this as I hear the GPU's fan rev up, so at 928 MHz it's power usage shoots up to ~300w! Their must be a large increase in voltage for that kind of leap in power use, a 31% power increase for a 9.2% clock speed increase!

Think I'll leave it at 850 MHz all said and done, as it's much quieter too at that speed! :)
 
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