Desktop Performance of 512MB Model B vs 256MB Model B

Question

My 256MB Model B Raspberry PI failed a few months ago while I was at university, I don't think it liked being shut away in my box of cables.

I am going to buy a new PI for some projects I have in mind to do with the rest of my summer. I am wondering what the desktop performance is like with the newer 512MB PI's.

I remember my 256MB Pi was rather clunky / laggy with general desktop performance, moving windows about the screen etc, even with just a text editor open. I remember the web browser being another program which made the desktop lag and CPU rise to 100% nearly all of the time. I was using Hardfloat Debian by the way.

Im guessing this was due to the shortage of ram, and the PI having to write to the SD card continuously to the swap space.

Are the newer 512MB PI's significantly different? I don't actually require desktop performance for my embedded projects. They will run from the command line anyway. I only need access to the IO. Anyone got any experience of using the older 256MB model and the 512MB version? If so I'd like to hear what you think about performance differences.

You can relate this to general performance, eg if you wrote some programs yourself in C/C++, if you like.

Answer 1

From this Raspberry Pi post:

If you're familiar with the Raspberry Pi desktop experience, you'll have noticed that windows on the desktop can be a bit slower to move around than you're used to on your PC or laptop. This is because X, the windowing software (or composition protocol) that we use, is not optimised to use the graphics core of the BCM2835, the chip at the heart of the Raspberry Pi. All the work is done by the ARM processor instead, which slows things down and leaves the graphics core twiddling its thumbs. That graphics core is extremely powerful, so we’re working on putting it to good use to fix the issue.

As you can see from that, RAM does not have much to do with graphics on the Raspberry Pi. I'm not saying that it isn't important, it just isn't the main problem with the graphics. Therefore, more RAM will not make a significant impact. However:

We've made the decision to bypass X completely. Over the past few months we've’ve been working with our friends at Collabora to implement the open-source Wayland composition protocol on top of the BCM2835 hardware video scaler (HVS). The HVS is a very powerful piece of hardware, with a scaling throughput of 500 megapixels per second and blending throughput of 1 gigapixel per second. It runs independently of the OpenGL ES hardware, so we can continue to render 3d graphics at the full, very fast rate, even while compositing.

So work is being done to make the desktop experience faster, it's just not ready yet. According to this:

We're still working to improve performance and memory consumption, and don't expect to be able to replace X11 as our default desktop environment until later in the year, but we will be including a technology preview in our next Raspbian release.

It will be out later this year.

How to test Wayland now:

1. Add deb http://raspberrypi.collabora.com wheezy rpi to /etc/apt/sources.list

2. $ sudo apt-get update

3. $ sudo apt-get install weston

4. $ sudo weston-launch