Computing stuff tied to the physical world

Speedy Raspberry

In Hardware, Linux on Jun 3, 2013 at 00:01

The Raspberry Pi is an amazing little board, with an amazing amount of power and functionality at an incredible price – it’s probably fair to say that our technology geek’s world will never be the same again, now that we have the RPi.

But it’s no speed monster…

Sometimes during development, it really gets in the way – especially when you’re used to working on a modern fast laptop, which is some 20 times faster (and that’s per-core).

So I decided to overclock one of my RPi’s, and see what it does. Overclocking in Raspbian is trivial with the standard raspi-config utility:

Screen Shot 2013-05-28 at 16.52.58

Just go to the Overclock section, and pick one:

Screen Shot 2013-05-28 at 16.46.48

I went for the fastest there is, but decided to run a 2-hour test to make sure it really works. Turns out that someone has already done all the work, and even created such a stress test:

root@raspberrypi:~# ./overclock-test.sh 
Testing overclock stability...
reading: 1
945+1 records in
945+1 records out
3965190144 bytes (4.0 GB) copied, 352.455 s, 11.3 MB/s
reading: 2
[...]
reading: 10
945+1 records in
945+1 records out
3965190144 bytes (4.0 GB) copied, 358.522 s, 11.1 MB/s
writing: 1
512+0 records in
512+0 records out
536870912 bytes (537 MB) copied, 95.2065 s, 5.6 MB/s
writing: 2
[...]
writing: 10
512+0 records in
512+0 records out
536870912 bytes (537 MB) copied, 83.4848 s, 6.4 MB/s
./overclock-test.sh: line 18:  2414 Terminated
              nice yes > /dev/null
CPU freq: 1000000
CPU temp: 58376
[    5.217175] Registered led device: led0
[    8.943589] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[    9.418819] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[   19.181046] smsc95xx 1-1.1:1.0: eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
[   19.431053] bcm2835-cpufreq: switching to governor ondemand
[   19.431082] bcm2835-cpufreq: switching to governor ondemand
[   21.736829] Adding 102396k swap on /var/swap.  Priority:-1 extents:1 across:102396k SS
[   22.134893] ip_tables: (C) 2000-2006 Netfilter Core Team
[   22.174573] nf_conntrack version 0.5.0 (7774 buckets, 31096 max)
[  750.951153] smsc95xx 1-1.1:1.0: eth0: kevent 2 may have been dropped
Not crashed yet, probably stable.

Ya gotta love that last message, nicely semi re-assuring ;)

I did fit a set of cooling fins from Watterott (some nice IR heat pictures there):

DSC_4475

As checked with vcgencmd measure_temp, the temperature never rose above 58.4°C.

Onwards!

  1. But: how is the lifetime influenced by this overclocking?

    • Should be fine – the heat sinks keep the temperature low, which is what matters here. General guideline is to keep the chip’s own temperature readout under 70 °C, is what I’ve read.

  2. Raspi is a cool system. It’s not completely open (Broadcom data sheet requires an NDA, for starters) and there’s no guarantee that any version will be available 5 yrs or even 6 months from now. For OEM use where such things are important, you might also like the Beaglebone Black, for about the same price, but it is completely open. It’s faster and different, but since both are Linux, the same tools should run on either, allowing good portability of apps. BBB is not so good as a media center (it just does 1280×1024) but looks to be better as a headless embedded system, or with a local color touchscreen (7″ and smaller are available from CircuitCo who also make the BBB). We just received some BBB for an OEM project so will know more soon. We plan to program in Python with C/C++ where needed for drivers.

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