I have a 8gb Pi4 and a old S8 phone. The phone gets more results.

The machine does all 5 projects in whichever order they come in so I will have to dig into the stats to single out OPN but on average they each take 1.25 to 1.45 hours. Same goes for real power consumption. Have no tools to measure so I will have to deduce the numbers from the Internet: motherboard, fan, disk, and an old graphics card 12+ years old.

Yes but you got 15 of them plus a switch plus cables plus eMMC cards; not exactly a limited budget unless we have a different definition of "limited budget". I sure we don't so I get the idea.

Will post those numbers later.

ok, the data is not exactly compareable, but we see Raspi&Co are not far away at all (WUs / Watt / day).

Regarding the budget i just mean that one Raspi or similar is a great piece of hardware to support WCG.

It is about to help and these small boards do help in a quite efficient way. They do outperform many older and quite actual PCs with a small entry budget.
Also it is easy to add more by time..whenever the budget allow it.
But you can not buy half a PC :-)

I was just comparing my Pi4 to a cracked screen hand me down S8. The S8 running android 11 and boinc does better than my Pi4. Old S8 phones are easy to find and have 8 cores. I run 6 cores at a time. As far as my other devices, Ryzen 3800XT/GTX 1660 does all the heavy lifting. 😁

This is true about older PCs on eBay. One thing to check is the actual CPU installed along with the fastest which can be installed on the motherboard. The faster CPU can probably be bought cheap too. You can check the specs of CPUs at https://www.cpubenchmark.net/cpu_list.php (no connection to me) and then judge by cost/speed. I also did this on the cheap for an off-lease HP (not on WCG). Went from 2/4 core 2.5 GHz to a 6/12 core 3.3 GHz.

If you like to tinker you can also replace the motherboard of an old working clunker which you can probably get at a garage sale for next to nothing.

The case I was making was to compare the work done with these small devices. The writer above has 15 of them; not exactly a limited budget. My estimate is that he spent about the same I did for his setup as I did. Except he would need about 30 to put out what my 1 machine does. We could argue about wattage.

You say it's the quantity that matters. I agree. Speed puts out that quantity a little faster.

Not disparaging Pi's. I you got them use them.
If you are buying and want to put out numbers, then calculate it all out.
Get a Pi if that old clunker will only put out the same as a Pi. Don't buy the clunker.