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> The things use like ~1W of power, so the board itself is surprisingly efficient compared to a "real" server.

Try 3.5 watts[1], not counting overhead of most USB power bricks being incredibly inefficient.

A current-gen 35W laptop CPU will be some 10 times faster[2] as a RasPi, have much faster storage available (SATA3 or NVMe versus… USB2), much faster I/O (GBit LAN and GBit Wifi versus… USB2), and a lot of other benefits. (Like an integrated screen and battery and keyboard and …) It also won't need external hardware to communicate with other cluster members – that 10-port ethernet switch will need power, too.

One RasPi is relatively energy efficient; RasPi clusters… not so much.

> But really, I think the primary use case is cost.

Indeed.

[1] http://raspi.tv/2016/how-much-power-does-raspberry-pi3b-use-... , see the numbers for "Multi-threaded CPU Tests", which is the most applicable for server workloads

[2] Running that script manages ~9 runs/second on an i7-6700HQ, vs. ~0.9 run/second on a RPi3.




They're using Pi Zero's in this post, which draw much less than others, between 0.4W and 1.0W, probably safe to assume 0.7W as an average load [1]

And at $5 each, if we're talking hardware costs for setting up a "toy" cluster for, say, self-learning or student labs, that's hard to beat. I suppose you could do better using VMs for a virtual cluster, but that adds other complications unrelated to the clustering task. But I agree there doesn't otherwise seem to be much practical purpose here, and the overhead of running an OS on each Pi really cuts into performance compared to a single chip w/ multicores instead.

[1] https://www.jeffgeerling.com/blogs/jeff-geerling/raspberry-p...


If you had ten of them, ideally you'd use a USB power supply where that overhead is a much lower percentage.


You can probably shave off another .2W by disabling the HDMI and LEDs, but an RPi3 at load will probably be at 4+W from the wall.

At the same time, you're comparing the power consumption of lets say 10 whole RPis/platforms to the consumption of a single processor. Stick that processor in a platform (laptop), and it's going to use much more than 40W.

Like you said, you get a lot more with the laptop, but given your benchmark (10x difference), my guess is that 10x RPis would still be more power efficient than a laptop with a 6700HQ at that specific task.


6700HQ is 45 W TDP?



/Looks at price...

Gets you 11 Pi's ... Gets you only 1 Intel CPU, no memory, motherboard, heatsink, fans.

Reminds me of the Celeron® Processor J3455... 10W rating on Intel there page. On AVERAGE! Then when you see the real power usage under load for MB + CPU + 16GB memory, its actually doing 35W.

Where as the Pi's are doing 3.7W max per piece. So even with 4 pieces to match the performance, your still half the wattage.

If Intel really scaled that good in power vs performance, why are we not seeing x86 phones all the time?




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