I hope I can share some ideas on cheap hardware on this forum to run Boinc projects.


I'm in the process of making a Media player array.
I went for the cheapest I could find on Ebay, hosting the Amlogic S905 chipset. (the one below):


However, their touted 2Ghz came out poorly only getting 1,2Ghz per core up to 2 cores, and 1Ghz up to 3 cores.
4 cores shuts down 1 core, and leaves the rest running at 1Ghz, probably due to overheating at 80C reported by CPUZ (will know more soon).
The media player uses a very thick thermal pad, and has a steel heat sink, built on the top of the device, that conducts heat pretty poorly.
Slightly better than running no heat sink at all, and certainly not recommended!

I am in the process of gutting these devices, and applying proper cooling, by taping thermal paste around the CPU, and directly sticking a larger heat sink on top of the CPU (covering the RAM modules as well).
Using 11mm hexagonal rods for spacers, to stack them all on top of one another (with optional washers for adjusting the height).

Additionally I plan on testing to see if using a 12V 80mm PC case fan at 5V, pushing air between the boards, will cool them better than when using thin dual sided tape (for both electrical insulation, with a small sheet of extra heavy duty aluminum foil as heat conductor.

For anyone interested, these devices may be good for watching a movie, but at 1-1.2Ghz crunching per core, they're way too slow!

There are 2 alternatives,
- The Amlogic S912 chipset with Octacore, however these devices go for double the price at $40 a piece (when buying in a lot),
- or the RockChip RK3229 Quad-core Cortex A7 players.

Both these devices (theoretically) run at 1,5Ghz on the first 4 cores (while the Amlogic S912 runs at 1Ghz on the little cores).
In the Amlogic S912 case, the big cores are probably going to be the only ones to crunch on.
On the Rockchip, all 4 ones should be accessible.
In other words, media players of $20-30 a piece (when bought in a lot) should average around 1,5Ghz peak; and below $20 a piece, they're locked at or below 1,2Ghz.

My first array of 8 media players is in process to be mounted on a 50W PSU, and a 8 port HDMI and 2x 5port USB hubs, all operating at 5V.
As well as connected to a 10 port router (also working at 5V).

My second array will be aimed towards the RockChip media players, and see how they perform against Amlogic.
I'll keep you posted.

OK, so in this price category, there are basically 3 chipsets that are interesting.
1- The Amlogic 905x,
2- the Rockchip R 3328,
3- and the Alwinner H6.
All of them are most common Android based media players found on Ebay, that run between Android 6.x to Android 9.x. (possibly Android 9 on all of them).
This means they're good to go for Boinc. Once the newer devices come out with Android 10, for those devices, this project won't work anymore (unless the Android Boinc compatibility issues somehow get resolved).

The Rockchip seems to be the most expensive one.
The Allwinner H6 seems to have the best CPU (Highest continuous CPU score), which is what matters for boinc.

Please be aware that all of these media players are about half as fast as a modern Snapdragon 800 series cellphone (SD835 and up, SD 600 series (Krait 400 or up)). Though cellphones of this caliber are going for $150-300 and up, while these media player boards with remote, and power adapter go for $20-25.

I have ordered an Allwinner H6, and an Amlogic 905x media player.
Will test them both, and compare it to the AMlogic 905w that I currently own, and keep you posted.

I have decided to not continue with the Rockchip, due to expensive price, and lower CPU benchmark results found here

The first 4 units, running an Amlogic 905W have come in, and I have the results in.
Idle consumption, with media players off = 2.3W (just USB and HDMI switcher):




With all units powered on (not doing anything), I get an average power consumption of 12.75W.
With a proper heat sink, the hottest player, doesn't surpass 79C, while the coolest player maxes out at around 65C.
This is passively cooled. Active cooling will only be necessary when I increase the amount of units (eg: 2 rows of 8 units stacked).
All 4 units, running 4 cores at 1,2Ghz passively cooled.
Boinc Android doesn't supply any flops rating.

Power consumption at full load, peaks at 17W, and averages around 16,5W;
With all 4 units powered on, but without crunching ran at around 12.75W, averaging around 1 watt difference.

I was able to get 0.4W lower (0.1W per unit) by disabling the wifi signal on all units, as well as location.
I also noticed the total wattage dropped by 0.9W, whenever the monitor turned off (HDMI).

The unit's high idle power consumption somewhat surprised me, as each unit consumed roughly 3 Watts just idling, while .




Memory used by Boinc for 4 projects was still good (482MB out of 855MB was used, with memory usage settings set to 80%).
I've ordered 4 more, and more are on the way.

I'm just penning all this down, for anyone who wants to save some research time,
After looking at more online spec sheets and benchmarks, I found that:
The cheapest media players on Ebay right now, are the Amlogic S905W units, going for <$25 a unit.
For about $5 more, you can buy the Amlogic S905X3 (X = Extreme model, 3 is third revision. On paper they should run at 1,9Ghz, vs 1,8Ghz for S905X2, and 1,7Ghz for S905X).
For Boinc, a minimal of 512MB of RAM, and 4GB of ROM is needed, when running Android 4-6.
Android 7-8 doubles that.
Android 9, will need preferably 2GB of RAM and 8GB of ROM.
Not much more is needed for most projects.


The S905 (first gen) is a chipset from 2016, built on 28nm (which was way more efficient than the 40nm Rockchip of that time; this Rockchip is comparable to 12-14nm x86 CPUs in efficiency).
The S905X3 (third gen) should be a chipset from 2019 (one upgrade per year), built as an upgrade from x2, they're built on 12nm, meaning, even more efficient!

It makes more sense to pay the $5 extra, for the extra performance of the 905X3, that is, if the media player has this power unlocked, but also benefit from the chip's lower TDP!

The Amlogic 912 is comparable to an Amlogic 905W to 905X CPU (from the reviews) in CPU performance, with an improved GPU (not utilized by Boinc); while the next version (S922X) is more than double the price, and might not be worth purchasing.
If you want higher performance, Nvidia's Tegra X1 chipset (going for $10 more than an S922X (at $110 on some sites), might make more sense).

Both S912 and S922 series have a Big-little setup. Unless Boinc can effectively use all 8 cores, the 905(X3) might make more sense (which has a higher clocked CPU, but only 4 cores).

Order's on the way. Will know more in 2 weeks!

Project discontinued due to it being inefficient.
While the Media players use way less hardware than a server (they could crunch through many different projects at a time), they also took nearly half a day per project (vs 5-120min on GPU).
While they were more efficient than CPU crunching, I now only focus on GPU crunching (save for 1 or 2 projects that don't do GPU).