Zu kaufen gibt es das gute Stück bei uns: shop.pi3g.com
Zu kaufen gibt es das gute Stück bei uns: shop.pi3g.com
As we all know, it is now possible and allowed to overclock the Raspberry Pi. It even helps to overclock the GPU, as RAM is accessed through it.
In our quest for more power we should not forget that the Firmware of the Pi limits the maximum temperature of the SoC which contains the CPU and the GPU. This is a good thing – it literally protects your Pi from melting down.
One of the huge advantages of a fan-less low-power system like the Pi is it’s totally noiseless. (Good for concentration and stress levels!)
Although a fan could be used to disperse the heat, we prefer a passive cooling solution.
Our partner TEKO has created a kit consisting of three heatsinks with cooling fins, and a high quality heat conductive double faced adhesive tape.
You can buy the cooling kit for the Raspberry Pi through our online store.
These are some measurements we have taken with our case (also produced by TEKO) and cooling kit, using OpenELEC and playing back DVDs. In this measurement we have used only one heatsink of the kit, on the SoC / RAM. Later on, we will also test the system’s performance with the other heatsinks added.
The temperature values were taken from the OpenELEC system information menu after letting the DVD play for some minutes for each measurement, allowing the system to cool down / heat up. The processor usage displayed by OpenELEC oscillated between 93 – 96 % in each case.
As you can see, the Raspberry Pi is running a bit hotter inside the case (about 10 degrees hotter), while the heatsink allows the Pi to operate at about 15° cooler temperature. For optimum performance and heat dissipation, leave off the case lid and add the heatsink.
Also another effect: as the overlaying of menus (done very smoothly in the newest OpenELEC release) consumes additional general purpose processing power, the Pi is running hotter when the menu (in our case the system information menu) is open!
We will be investigating some more into this, also into alternative cooling solutions.
TEKO has gratiously provided some more results, measured professionally with a infrared camera:
Before cooling kit was mounted:
After cooling kit was mounted:
Please note the different measurement scales on the right! While the SoC appears to be only a bit cooler, it is in fact 10 ° cooler, which confirms our findings.
Also note, how the heat dissipation area has increased.
Right now I am evaluating the new BerryBoot and OpenELEC version – it works great for DVD playback, and uses the full 512 MB without extra configuration!
It runs BerryBoot (release from December 2012), with the newest OpenELEC (also released in December 2012) – installed from berryboot. If you don’t know berryboot yet, you should check it out. It allows for a Multi-boot Raspberry Pi environment and can install a choice of distributions by click of mouse.
I also have the MPEG-2 and VC-1 decoder licenses installed on the Pi. They are necessary for fluid MPEG-2 decoding (DVD codec).
OpenELEC accessing the full 512 MB (some is reserved for the GPU). No special modifications / settings have been done to achieve this – it just works
As has frequently been written elsewhere, the main source of problems for the Raspberry Pi systems is the power supply. I would even go as far as saying: before debugging anything else, measure the voltage!
On the Raspberry PI two test points are located. TP1 and TP2. With a voltmeter you can measure the voltage between them. According to the Raspberry Pi handbook by Eben Umpton (page 49) it should be between 4,8 V and 5 V.
I am testing several different power supply units (mostly USB chargers …), and will be offering only know good units in the shop. By buying a known good power unit you can avoid the following
Even if your power supply states that it will provide up to 1 A, this will not necassarily be with 4,8 – 5 V – many supplies I’ve tried show this behaviour.
According to Gert van Loo, whom I met at the fair, the Raspberry Pi will take at maximum 1 – 1,5 A, depending on the ambient temperature, before the fuses start kicking in. As such, there will be no point in trying to attach a 4 A powersupply, for instance, in order to provide power to the USB ports.
The following adapters or compatible, thoroughly tested, models will be available in our shop:
goobay Model 42438 car adapter (12 V -> 5 V)
Provides between 4,94 V and 5,10 V in our tests. It has a micro USB plug.
D-Parts Mobilphon & Zubehör Gmbh (DP-LGS) Model AC0122-051000 (230 V -> 5 V)
Provides 4,93 V in idle mode. It has a micro USB plug.
The power drawn from the Raspi in our tests has been measured at roughly 500 mA – well below the 1 A level specified by the vendors of the following adapters:
LogiLink USB Travel Charger Combo Kit PA0008A v2.0
This (white) mains power supply is quite unstable and NOT suitable to power the Raspberry Pi. It will provide about 4,3 – 4,6 V under load / in idle mode, at about 0,5 A of current being drawn. We’ve tested two supplies of this series. Another downside: the USB plug will not have a good, secure fit in it’s outlet.
We’ve also seen huge oscillations in the voltage with it – ranging from about 3,9 V to 5,1 V.
All in all, the Raspi will display the known symptoms (see above).
The car adapter (which converts 12 V to 5 V) also runs at 4,74 V with the Raspberry Pi in idle moad (no load).
The package states that it will provide 1 A. Maybe. But probably not at 5 V.
FRIWO FW7713 (230 V -> 5 V)
This adapter performs better than the LogiLink one, still voltage levels drop below the magical 4,8 V level. Under load we have measured 4,68 V / 4,62 V for instance. (With a nominal 460 mA load from the Raspi).
The USB plug has a more secure fit than in the Logilink counterpart (see above).