Imagination PowerVR SDK Blog

PVRShaman Extremely Slow on OSX Mountain Lion



Hi there,

I’ve noticed an incredible drop in performance when using PVRShaman since I upgraded to OSX Mountain Lion.

To give you an idea of how slow: when I click on something ~5 seconds can pass before anything happens :frowning:

Everything used to run really well, so I can’t think what has happened. Installing Mountain Lion is the only change to my set up that I can put it down to.

Interestingly, I’ve tried running the older X11 based version and it is also just as slow on Mountain Lion.

Any ideas? Is anyone else having this problem?




Hi Andre,

We’ve not heard of any performance problems on Mountain Lion before. The lead PVRShaman developer’s main machine is an iMac running Mountain Lion, so I’m not sure how performance would have degraded without him noticing.

He’s out of the office this week, but I’ll ask him to take a look ASAP.




Hi Andre.

Does this happen with the sample files we distribute with PVRShaman? As Joe said, we’ve noticed no slow-down on any ML Macs we’ve ran on - not compared to previous OS revisions anyway. Is your machine particularly old or unusual in any way?


Hi Arron,

I’ve just checked and your samples appear to work perfectly.

The odd thing is I’ve been working away at my POD/PFXs for on and off for a year and it is only now that the slow-down has happened. I also have many previous versions of the files in separate folders going right back to the start of my project, and they all now seem affected by the slowdown!

I just confirmed this by opening a file I last edited over a year ago. I got an error that the previous versions of PVRShaman didn’t catch about not specifying a precision for a variable - I fixed this and then my model is displayed correctly but everything runs really slow.

I quit out of the 3.1SDK Shaman and opened the same file in the old X windows version - this time it doesn’t notice the missing precision keyword, and it displays the model - yet it is also really slow!!

My machine hasn’t changed in the past year: It is a Macbook Mid 2010 (last model they made) with upgraded memory to 8GB, and 1TB hard drive. It usually runs really well.

The only change that I can think of is my upgrade to Mountain Lion.

I’m really at a loss :frowning:


Hi Andre,

Our 3.2 SDK and OS X Mavericks have been released since we last spoke. With our latest version of PVRShaman and the latest OS, is the situation any better?

If you can narrow down the issue to a POD or two that exhibit the issue, we can look into the problem for you.




Hi Joe,

I’ve upgraded to Mavericks and I now use the current 3.2 SDK & Tools. Unfortunately the issue is still present.

I’m happy to send you a POD & PFX that exhibits the problem. I’ve zipped it up but its still 30MB (there are four large textures included).

Can I send it via email?




Sure. You can send it to




Hi Joe,

It was too large to email, so I just emailed you a link instead :slight_smile:




Hi Arron,

Thanks for looking into it.

I’ve run some tests as you suggested with smaller textures.

If I resize them all to 1024x1024 then it works fine.

It’s still a puzzle to me how the issue never showed up until recently though.

Nevermind, at least I know there is nothing seriously wrong with my code - or yours! I’ll just have to create a few lower-res textures for use during development.

Thanks again,



Hi Andre,

Glad to hear you’ve found a workaround :slight_smile:

What size textures were you using before? Potentially, changes to the OpenGL graphics driver between your previous OS X revision and Mountain Lion are responsible for the reduced performance.




That sounds possible, because the older versions that worked well previously were still using 4096x4096 textures. Also I had to reinstall x11 (xQuartz) after the upgrade to ML in order to use the old PvrShaman, so something must have changed in the graphics system with ML.

I’m working on a different part of the system now, but when I come back to the shader code again I’ll do some more tests. I’ll update you guys with anything new I find out.

Kind regards,