Featured Articles
Announcing Pi
Technical Specifications
Raspberry Pi FAQs
Win a Pi
GPIO Pinout
Raspberry Pi Wishlist
Comparison Chart
Quiz
Group Actions
Engagement
  • Author Author: Gough Lui
  • Date Created: Date Created
  • Views 1931 views
  • Likes 5 likes
  • Comments 8 comments
Related
Recommended

A Date with the Raspberry Pi 2 (Model B)

Gough Lui

I'd have to thank element14, especially for this "mystery date" which turned up on my doorstep unannounced.

 

image

 

I've done some comparisons, benchmarks and high-resolution photographs on my blog here: Valentine’s Day: A Date with the Raspberry Pi 2 (Model B)

 

image

 

In short, the conclusion reads:

It seems the Raspberry Pi foundation aren’t under any illusions as to the reasons behind their success, and the latest Raspberry Pi 2 Model B retains the key points that has driven the Raspberry Pi’s success – namely, the low cost, and straightforward backwards compatibility, which allows for the platform to feel “homogenous” without being hemmed in by the original choice of hardware.

 

While the benefits of the increased core count will not necessarily be apparent to single thread tasks, the CPU also delivers with a more recent architecture which allows the performance per clock to increase. As a result, it appears the new CPU has much better single thread performance in part due to better caching and memory bandwidth, even comparing a stock Pi 2 to an overclocked Pi. The multi-core advantage makes sense for many tasks, as they may involves running multiple threads – think of certain server tasks with a thread per connection, dynamic content generation invoking multiple tasks, using one Raspberry Pi to do multiple things (e.g. attaching several RTL-SDRs), handling data and display on the same unit or handling multiple sensors.

 

It’s amazing that they’ve been able to work closely with Broadcom to specially produce the BCM2836 for the Pi 2, no doubt in part due to the major sales volumes generated. Through their refinement, they have been able to keep the cost identical, while offering so much more. In everyday use, the difference is very noticeable, from boot times through to actually using the device. It is much more pleasurable to use interactively, with less patience required compared to before.

 

Of course, being the natural evolution of the Raspberry Pi, it is expected that most purchases from now-on will be of the Raspberry Pi 2. Is there any downside? Well, the only one I can see is in power consumption under load and incompatibility with non-upgraded distributions (not so much an issue for Raspbian based OSes) – but aside from that, it’s pretty much a free lunch!



  • in reply to bluescreen

    No problems. Glad to hear that you think it will be useful image.

     

    - Gough

  • Hey Gough--

     

    Thank you for giving us permission to move it. By placing it in the Raspberry Pi 2 area, we can drive a lot more traffic to it and introduce your work to a larger audience here on element14. image

     

    I'll move it over in the next few hours if that's ok with you.


    Cheers,
    Sagar

  • in reply to bluescreen

    - Is there any way to "add" a post into a different area without moving it entirely? without needing to copy and paste it into a new post?

     

    Ideally I'd like for (a copy of) it to stay here just for the continuity of my blog area, although I do realize that it would probably appeal much more to the Raspberry Pi 2 area. I'm all in support for having it there as well.

     

    EDIT: On second thoughts, even if we can't have it in both areas, you have my support for moving it over image

     

    - Gough

  • Hey Gough--

     

    Nice post! Mind if I move it into our Raspberry Pi 2 area?

     

    Sagar

  • in reply to clem57

    - thanks for bringing this to my attention as I wasn't aware that the original Pis had another memory option. I was aware of the Samsung and Hynix options, and for reference, I've never owned anything but ones with Samsung Package-on-Package for the Rapberry Pi B and B+'s. My older Raspberry Pi 1's with Samsung RAM are marked with K4P4G324EQ-RGC2, K4P4G324EB-AGC1, etc. In fact, my old article about the B+ has pictures of the test candidate B and B+ here (Review: Raspberry Pi Model B+ & Multicomp Raspberry Pi B+ Case).

     

    Despite the link to OpenEnergyMonitor saying that they needed new firmware to boot with the Micron part, they claimed no performance difference. I would have assumed by now that the LPDDR2 that they use is relatively standardized (JEDEC normally look after it all, and I would suppose for an interchangeable part, there isn't really a choice in pin-allocation to worry about), so maybe there could be something different about the internal arrangement (row/columns) of RAM cells, or latency/timings of the new part that could play a role in the performance, especially if it's better matched to the CPU design.

     

    As a bit of an overclocker when it comes to regular desktop machines, I do wonder if we would ever get any chance to play with the latencies (e.g. CAS, RAS, RP, etc) to further optimize the RAM bus, although I suspect it's not something that many will demand. Regardless of this, the benchmarks do show significant discrepancies in the RAM access speed which is suggestive of a decent CPU cache and a better RAM bandwidth. I suppose a Quad core CPU does need to be "fed" with more data from the RAM to keep it busy, so improvements in this area are very welcome, but it also produces a side effect of further boosting single threaded performance. Someone did another benchmark somewhere, single threaded, claiming to see 6x performance increase in their workload, which is not entirely out of the question.

     

    The Pi 2 that I received, as you can see in my images, comes with an Elpida package - but interestingly, Elpida is no longer the company they once were, having been acquired by Micron. The Raspberry Pi 2 press release notes the following:

    This has an identical form-factor to the existing Raspberry Pi 1 Model B+, but manages to pack in both the new BCM2836 and a full 1GB of SDRAM from our friends at Micron.

     

    I wonder whether that is indicative that they have some sort of strategic relationship, meaning that Samsung and Hynix parts will be purged from their lines ...

     

    - Gough