Why The RP1 Is The Most Important Product Raspberry Pi Have Ever Made

We’ve had about a week to digest the pending arrival of the Raspberry Pi 5, and it’s safe to say that the new board from Cambridge has produced quite some excitement with its enhanced specifications and a few new capabilities not seen in its predecessors. When it goes on general sale we expect that it will power a slew of impressive projects in these pages, and we look forward with keen anticipation to its companion Compute Module 5, and we sincerely hope eventually a Raspberry Pi 500 all-in-one. It’s the latest in a line of incrementally-upgraded single board computers from the company, but we think it conceals something of much greater importance than the improvements that marked previous generations. Where do we think the secret sauce lies in the Pi 5? In the RP1 all-in-one PCIe peripheral chip of course, the chip which provides most of the interfacing on the new board. Continue reading “Why The RP1 Is The Most Important Product Raspberry Pi Have Ever Made”

Raspberry Pi Reveals A Little About Their RP1 Peripheral

The Raspberry Pi 5 is the new hotness from the Cambridge-based single board computer vendor, thanks in part to its new wonder-chip peripheral that speeds up much of its interfacing with the world. The RP1 hangs of the CPU’s PCIe bus and takes on many functions previously in the SoC, and those curious about it now have a little bit of information. Eben Upton has posted an article about the chip, and there’s a partial datasheet and a video in which the engineers talk about the chip as well.

The datasheet is intended to help anyone wishing to write a hardware driver for a Pi 5, and they admit that it doesn’t reveal everything on the silicon. We don’t expect them to put this chip up for sale on its own because doing so would enable their competitors to produce something much closer to a Pi 5 clone. It does reveal a few nuggets, though; there are a couple of Cortex M3 cores for housekeeping, and alongside all the interfaces we know from earlier boards it has, perhaps most interestingly for Hackaday readers, a 12-bit analogue-to-digital converter. This has always been on our Pi wishlist and is a welcome addition.

So, if you read the datasheet and watch the video below, you’ll learn a lot about the interfaces and how to talk to them, but not quite so much about the full workings of the chip itself. They hint that there’s more to be released, but since the Pi people have a history of not letting go of the family silver, we won’t expect the keys to the kingdom.

Have a read of our Pi 5 launch coverage.

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Overclocking Raspberry Pi 5’s SoC To 3 GHz And 1 GHz GPU

Overclocking computer systems is a fun way to extract some free performance, or at least see how far you can push the hardware before you run into practical limitations. The newly released Raspberry Pi 5 with BCM2712 SoC is no exception here, with Tom’s Hardware having a go at seeing how far both the CPU and GPU in the SoC can be pushed. The BCM2712’s quad Cortex-A76 CPU is normally clocked at 2.4 GHz and the VideoCore VII GPU at 800 MHz. By modifying some settings in the /boot/config.txt configuration file these values can be adjusted.

In order to verify that an overclock was stable, the Stressberry application was used, which fully loads the CPU cores. Here something like a combination of stress-ng and glxgears could also be used, to stress both the CPU and GPU. With the official actively cooled heatsink the CPU reached a temperature of 74°C with a whole board power usage of about 10 Watts. At idle this dropped to 3 Watts at 46°C. At these speeds, the multiple Raspberry Pi 5 units OCed by Tom’s Hardware were mostly stable, though one of the team’s boards experienced a few crashes. This suggests that this level of OCing could still be subject to luck of the draw, and long-term stability would have to be investigated as well.

As for the practical use cases of OCing your Raspberry Pi 5, benchmarks showed a marked uplift in compression and Sysbench benchmark scores, but OCing the GPU had no real positive impact on YouTube or 3D performance, leading even to a massive increase in dropped frames with video playback. This probably means that increasing the CPU clock may be beneficial, but OCing the GPU could be futile without also OCing the RAM frequency, if at all possible.

Realistically, the Raspberry Pi SoCs never were speed monsters, with even the Raspberry Pi 4B’s SoC being beaten handily in 2020 by a budget dual-core Intel CPU.  The current Intel Alder-Lake-N-based N100 SoC has a 6 Watt TDP and boosts up to 3.4 GHz while its Xe-LP-based iGPU (with AV1 decoding support) makes for a decent gaming experience within a ~16 Watt power envelope. Clearly, any OCing of the Raspberry Pi boards is more for the challenge of it, but then so is running the latest Intel CPU at 10 GHz with liquid nitrogen cooling.

A Raspberry Pi 5 Is Better Than Two Pi 4s

What’s as fast as two Raspberry Pi 4s? The brand-new Raspberry Pi 5, that’s what. And for only a $5 upcharge (with an asterisk), it’s going to the new go-to board from the British House of Fruity Single-Board Computers. But aside from the brute speed, it also has a number of cool features that will make using the board easier for a number of projects, and it’s going to be on sale in October. Raspberry Pi sent us one for review, and if you were just about to pick up a Pi 4 for a project that needs the speed, we’d say that you might wait a couple weeks until the Raspberry Pi 5 goes on sale.

Twice as Nice

On essentially every benchmark, the Raspberry Pi 5 comes in two to three times faster than the Pi 4. This is thanks to the new Broadcom BCM2712 system-on-chip (SOC) that runs four ARM A76s at 2.4 GHz instead of the Pi 4’s ARM A72s at 1.8 GHz. This gives the CPUs a roughly 2x – 3x advantage over the Pi 4. (Although the Pi 4 was eminently overclockable in the CM4 package.)

The DRAM runs at double the clock speed. The video core is more efficient and pushes pixels about twice as fast. The new WiFi controller in the SOC allows about twice as much throughput to the same radio. Even the SD card interface is capable of running twice as fast, speeding up boot times to easily under 10 sec – maybe closer to 8 sec, but who’s counting?

Heck, while we’re on factors of two, there are now two MIPI camera/display lines, so you can do stereo imaging straight off the board, or run a camera and external display simultaneously. And it’s capable of driving two 4k HDMI displays at 60 Hz.

There are only two exceptions to the overall factor-of-two improvements. First, the Gigabyte Ethernet remains Gigabyte Ethernet, so that’s a one-ex. (We’re not sure who is running up against that constraint, but if it’s you, you’ll want an external network adapter.) But second, the new Broadcom SOC finally supports the ARM cryptography extensions, which make it 45x faster at AES, for instance. With TLS almost everywhere, this keeps crypto performance from becoming the bottleneck. Nice.

All in all, most everything performance-related has been doubled or halved appropriately, and completely in line with the only formal benchmarks we’ve seen so far, it feels about twice as fast all around in our informal tests. Compared with a Pi 400 that I use frequently in the basement workshop, the Pi 5 is a lot snappier.

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