Category Archives: Updates

OpenCL/Metal Rendering on Intel GPUs Works !

Fractal Architect version 4.5.0 submitted to Apple today (Dec 14, 2016) makes it possible to use either OpenCL or Metal GPU rendering with Intel processors.  This capability requires Mac OS Sierra.

With Mac OS Sierra, it seems that all Intel CPUs (2013 and later) having Intel HD, Intel Iris, or Intel Iris Pro GPUS can now take advantage of either OpenCL or Metal  rendering for HUGE speed increases. For example, a 2013 MacBook Air gets approx. a 9x speed increase !  That is like a baby going from crawling to Olympic sprinting.

On Macbook Pros and iMacs having both a discrete AMD GPU and an Intel processor with its integrated GPU, you can use both GPUs together for rendering. This gives you almost twice the rendering speed !

Thank you Apple for giving us great OpenCL and Metal drivers on Mac OS Sierra !!

Note: Older versions of Mac OS and Macs produced in 2012 or earlier may have compatibility problems. (But CPU rendering works fine.)

Fractal Architect 4 Version 4.4 – Metal Rendering on AMD + Nvidia

This release is almost ready.

I figured out how to workaround a key Apple Metal bug and now Metal rendering works on AMD and Nvidia GPUs too! With Mac OS Sierra, the Metal rendering has great performance.

Metal can render on 2 GPUs at the same time. For instance, the 2013 Mac Pro with its twin GPUs renders almost twice as fast.

You can also combine rendering using both Intel Iris Pro and AMD GPUs on a 2015 Macbook Pro. Tested on Mac OS El Capitan 10.11.6.

Both GPUs: 159.75 Mips      8.5X
AMD:                93.14 Mips       4.9X
Intel Iris Pro: 84.64 Mips       4.5X
CUP (4 core): 18.84 Mips      1X

Bug Fix: Fixed image gamma for Resume renders (restart render to add higher quality)

Metal Rendering on Intel, AMD, & Nvidia GPUs Works!

Sierra Metal is Working Well on AMD and Nvidia

With Sierra coming out shortly, Metal renders can be made on all 3 GPU platforms: Intel, AMD, and Nvidia using Fractal Architect 4 version 4.4.0.

Apple has done a very good job on the Sierra release. In general, Metal is working well, and for some older GPUs, OpenCL rendering now works again (El Capitan’s OpenCL drivers were so broken).

Both Mac OS El Capitan and Sierra support Metal rendering, but the quality of the Metal drivers varies depends on the specific GPU configuration and OS version used.

For example, on Sierra the AMD drivers are much faster than on El Capitan.

On 2013 Mac Pro, with 2 AMD GPUs, you can use both GPUs for even more speed using Metal (but OpenCL driver has a critical bug preventing usage of more than 1 GPU).

Warning – Sierra Metal may not work on your GPU

On El Capitan, my 2013 Macbook Air renders 10.5 X faster than CPU. On Sierra, the Metal compiler cannot compile the app’s kernels on the 2013 Macbook Air, resulting in no GPU rendering at all !

But 2015 Intel Iris Pro in Macbook Pro works great with Metal !

Evaluating Sierra First

Since GPU compatibility is so hit and miss, I recommend installing Sierra first on an external hard drive and trying it out on your Mac(s).

You boot off that external drive by holding down the Option key at boot and select the external drive from the list shown at boot time.

Since normal hard drives are so SLOW, I recommend the following external drive: Samsung 250 GB T3 Portable SSD. This has worked very well for me, and the cost is reasonable.

Evaluate both OpenCL and Metal

Apple’s OpenCL drivers have been very good on AMD GPUs, but don’t work at all on Intel GPUs. But that OpenCL on AMD, may be faster than Metal on AMD. So remember to try both to see what works better.

Intel GPU Rendering now works on all Macs since 2012

This is BIG News !

Fractal Architect 4  now fully supports Metal GPU rendering on all Macs built since 2012 (using the Mac’s Intel GPU). Version 4.3.3 of FA 4 has some critical fixes.

Last October, we reported issues with Metal rendering. Those issues have been resolved in version 4.3.3 of Fractal Architect 4.

With the latest Sierra Beta, OpenCL GPU rendering now works on Intel GPUs for the first time too.

The rendering performance increase is HUGE.

El Capitan 10.11.6  Performance using Intel Metal

2013 Macbook Air     10.5 X faster than CPU
2015 Macbook Pro      4.8 X faster than CPU

Version 4.3.0 Submitted to Apple for Review

New Features

New Render Modes

  • Normal, Transparent, Composite over Background Image, Composite Over Color

Drag and Drop any image (even other fractals) to make it the Background image (for compositing).

Control transparent image’s alpha mask using new AlphaGamma parameter.

Preview window has fixed aspect ratio for fractals with composited background image – same aspect ratio as the background image.

Render to File dialog boxes show the compositing background images width and height (and sets the output image’s width and height to the same values.

Continue reading Version 4.3.0 Submitted to Apple for Review

FA4 version 4.20 released


  1. Metal rendering support for Intel Iris and Intel HD GPUs on OS X El Capitan.
  2. Metal rendering does not work for all fractals.
  3. Metal rendering not supported for AMD and Nvidia GPUs at this time.
  4. Added Gpu Compatibility Report to GPU Trial Window
  5. Removed color matching code not compatible with OS X El Capitan
  6. Removed color out-of-gamut check and soft proofing from Preview window not compatible with OS X El Capitan
  7. GPU Trial window now has Enforce Quarantine checkbox.
    Turning it off allows you to do trial renders on quarantined GPUs.
    Alert shown when you turn off the quarantine.

Metal rendering can cause GPU hangs for certain fractals (about 10% of them). GPU hangs cause your Mac to freeze for about 10 seconds (while the GPU restarts).

Normally, we would not have released this enhancement with the potential GPU hang issue, EXCEPT that on Intel GPUs the render speed performance is really good.

For those of you on Macbook Airs, we are getting 9 to 12X faster renders. You will experience GPU hangs with some fractals, but you always have the option of rendering those on the CPU — slower but robust.

Because of this GPU hang issue, Metal rendering is ONLY used in the app where you render a single fractal at a time – Preview window, Render to file, Quicklook.

Note: Intel HD 4000 (an older GPU) Metal rendering does not work on El Captitan 10.11, but it does work on 10.11.1 Beta. Its a slow GPU, so the performance is only 40% faster than on CPU.

Metal Rendering On OS X El Capitan

Version 4.2.0 of Fractal Architect 4 adds GPU rendering support for Metal on OS X El Capitan.

Lets be honest about the state of Metal Compute on Mac OS X in the initial release of El Capitan OS X. There are a lot of critical issues on all of the GPU platforms, AMD, Nvidia, and Intel. Only the Intel platform is stable enough to support this app’s flame fractal rendering algorithm. But it has significant issues too.

Render Performance using Metal on OS X El Capitan GM

(Mips is Millions of Iterations per Second an internal app measure, that is directly related to render performance)

2013 Macbook Air using Intel HD 5000 GPU

CPU: 10.01 Mips
GPU: 87.60 Mips     8.75X faster than  using  CPU

2015 Macbook Pro with Intel Iris Pro

CPU:  25.68 Mips
GPU: 124.09 Mips   3.42X faster than using CPU

The 2015 Macbook Pro also has a AMD Radeon R9 M370X GPU. Here are the rendering speeds for it on OpenCL:

Yosemite 10.10.5      AMD GPU:        157.83 Mips
El Capitan 10.11 GM   AMD GPU:          87.92 Mips

Note that the OpenCL driver performance went down 45% from Yosemite to El Capitan – NOT good!

Important Note: We are experiencing GPU hangs with some fractals  using Metal Compute.  GPU Hangs are the bomb. Entire Mac acts like it has frozen for about 10 secs until GPU resets. This behavior is unique to Metal Compute.

Metal Compute Stability seen in testing

GPU Family Test Results
Intel Iris Pro GOOD:
+ Intel HD 5000   Performance 9 to 12X faster than CPU
  GPU Hangs on about 10% of fractals
  OpenCL drivers have no problems with this
Intel HD 4000 BAD: Very slow kernel compiles
GOOD: Performance 1.4X faster than CPU
AMD BAD: Kernel compile failure at 2 min 20 secs
Nvidia 650M GOOD: Kernel compiles in 5 secs
BAD: Garbage Output

FA 4 4.0.3 release submitted to Apple

A new update release of FA 4 is on the way.

  1. Fixed camera rotation animation
  2. Updated Intel GPU quarantine for new Mac models
  3. Made random generator’s garbage filter settings less confusing
  4. Random generator now has Reset Settings to Defaults button
  5. Random generator now has limit of 200 random fractal retries
  6. Animation configurator’s video preview popover stays open now
  7. Changing Sequencer segments’ offset an/or duration now works correctly
  8. GPU Trial window now always reports performance multiple as GPU Mips/ CPU Mips
  9. Render State window now reports the Initial Mips performance (so you don’t have to go to the Render Status Log to find it)

FA 4 Version 4.02 Released

Release Notes ===============

Bug Fix: for Loop/Morph Basic Animations being classified as Complex animations
Bug Fix: for Gallery fractals not rendering
Bug Fix: for final assembly of movie failing with sandbox exception
Bug Fix: for Quicktime Player not opening after movie rendered
Bug Fix: for Make Video not working with either variation weights or variation parameters