Raspberry Pi patch adds warranty-safe overclocking
1GHz Turbo Mode debuts
The Raspberry Pi Foundation has equipped its credit card-sized computer with an overclocking - and overvolting - mode that doesn't tear up your warranty when you activate it.
The organisation is pitching the update as the introduction of a "turbo mode" which dynamically ups the core voltage and frequency but only so long as the thermals allow it. Intel's Core i CPUs do something very similar, and it provides short but high speed bursts of processor performance.
In the Pi's case, the system will push the board's BCM2835 SoC's frequency as high as 1GHz as long as the chip's temperature doesn't rise above 85°C.
Different parts have slightly different thermal characteristic, so don't expect one board to show the same turbo speed as another. The quality of the connected power supply has an impact too.
Users can choose from one of five peak frequencies, running up to 1GHz. The advice is: see how high you can go until you find a setting that renders the board unstable.
Tests carried out by the Foundation show "52 per cent faster on integer, 64 per cent faster on floating point and 55 per cent faster on memory" between standard and 1GHz turbo-enabled Pis.
The turbo mode arrives with a new version of the Pi OS, which also includes a number of other tweaks, most notably a lowering of the USB interrupt rate, which boosts performance by ten per cent, and enabling wireless operating out of the box for supported Wi-Fi drivers. ®
COMMENTS
Re: Why?
OK, I'll bite. Overclocking works because the manufacturer of the chip has tested it for the highest guaranteed clock. They err massively on the side of caution in the majority of the times, and so there is always room for overhead. The tolerances involved in the manufacturing process means there is always a safe overhead (they won't build a chip that *just* operates inside the clock frequency, as a minor glitch could make it go wrong) so it's a case of figuring out where that overhead reaches you. It's trivial to find too, run soak tests until it goes wrong. Pretty much every CPU will find 10% margin and that's without tweaking voltage levels.
Where are you finding a faster system than a Pi in that price range and that form factor then?
Us older geeks want to know..
When will they be introducing the cheesy LED display and 'Turbo' switch add-on board then?
Re: Why?
Longevity: Statistical analysis (what all chip companies do to determine longevity) indicates there will be some decrease in lifespan of the SoC on the Raspi due to overclocking+overvolting, but not enough to cause any problems. (i.e. still 20 years plus at 100% duty cycle).
So there is no downside to using this patch.
Still? Good greif...
I ordered my Pi's back In March, one RS and one from Farnell.
Then somehow I messed up and ordered a second from Farnell (this may be beer related).
I received my first Pi from Farnell. My second from Farnell turned up two days after they removed their "one per customer" restriction two weeks later.
My Pi from RS turned up 6 weeks after the second from Farnell.
I gave the extra one to a family friend's son who hasn't come out of his room since!
Over 6 months is a long old time to sort out a supply problem. I think RS should just give up, they're not making any friends with that level of service.
