If anybody is interested in the best compute per dollar for philanthropic CPU scientific computing, look no further than business class SFF machines such as HP prodesks, elitedesks and Optiplexes (and Thinkcentre m720s). A i5-8400 i5-8500 6 core 3.8 all-core box is often found to be $90 or less shipped on a popular auction site.

If you are interested in undervolting the best unit is Prodesk 400G5 because I have yet to find one with a bios downgrade locked. Important because have to downgrade to a early 2019 to 2018 version that supports undervolting (pre-plundervolt)

I have a large farm of these things and am happy to help if you want to start!

See playlist https://youtube.com/playlist?list=PLOvucQtyZA1-g2sgcCYPgVNRyOX0INXz8&si=0Q8oPLU0xIR2jl-h


I typically 100% reliably undervolt by 110mV using Throttlestop and set TDP limit to 50w. Test is to give it a full load when undervolted then idle it, will lock if iffy. More sensitive to undervolt when idle.

Chrome remote desktop is good for 300 boxes.

Windows 21H1 so Windows Updates and Defender can be nuked. Leave BOINC GUI closed also to save CPU cycles.

Power consumption Max 70w at all of CPU fan is full speed in a hot garage w/SSD. More like 60w if low speed. (If undervolted)

I typically have 20 units per 120v line, adheres to 80% rule.

If you have a 50A NEMA 14-50 outlet, it can power 7, 120v lines so 140 boxes, adhering to 80% rule. I can give links to quality splitters.



240V splitting Safety: In my experience with running computers off of 240 volt is the 240v side is all cool, splitters, outlet everything besides the breaker if heavily loaded.

The 120v side, the 4x splitters get warm if all 4 occupied fully but 2 or 3 per 4x it would just be luke warm. Each has dual 24A breakers on them so they do trip if things get weird

Further down the 120 volt lines as in the plug strips, warmish. The brand (hyper-tough Walmart 2 plugged into a DewinWils yellow strip each) I use they do trip if too much load.

Cords to each computer are all just ambient temperature because each computer takes about 0.5 amps. Each computer has a 180w power supply so with a 40 to 50w CPU power limit+ motherboard+ drive + fan it is about 65w max on summer, so about 40% load on the power supply.

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Bio-project WCG/SiDock/Rosetta cruncher whale ~320 Optiplex/Prodesk undervolted SFFs majority on WIFI. Chrome remote desktop has a limit of 300 so add another email. /danwat1234 Youtube see my setup on how to create your own inexpensive SFF farm

The ones at that price in UK at least only have 8GB of RAM. My main project has had Dev branch tasks taking more than that.
By the time I had upgraded three machines to have sufficient memory to run 15 tasks which is what I run at the moment, there isn't that much saving if any over what I went for which is one machine with 16 real cores.

(UK pricing. US pricing may change the goal posts.)

Mapping cancer markers with world community grid, Sidock work units take under 200MB per core, Rosetta up to about 800MB, Folding on CPU not more than Rosetta so 8GB for a 6-core business SFF is a good match for most BOINC/Folding projects. DDR4 2400MHZ is not spendy.

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Bio-project WCG/SiDock/Rosetta cruncher whale ~320 Optiplex/Prodesk undervolted SFFs majority on WIFI. Chrome remote desktop has a limit of 300 so add another email. /danwat1234 Youtube see my setup on how to create your own inexpensive SFF farm

Horses for courses. If my main project didn't have tasks that can use over 8GB/ task, the goalposts would make me consider it but for me, it is easier to have my main machine double up and have 16 cores, 32 threads all in one box.

I understand now! But what I am suggesting the community to do, is to run these headless not as a main machine so they only need enough RAM to prevent page file churning.
Stack 10 high very space efficient in a room. Inexpensive I5-8400/8500 400 G5 Prodesks that are certainly undervoltable with a BIOS downgrade should remain plentiful.

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Bio-project WCG/SiDock/Rosetta cruncher whale ~320 Optiplex/Prodesk undervolted SFFs majority on WIFI. Chrome remote desktop has a limit of 300 so add another email. /danwat1234 Youtube see my setup on how to create your own inexpensive SFF farm