imac pro

By Jason Yee, Support Engineer

Last week we were lucky enough to briefly get our hands on a shiny new space grey iMac Pro (2017). With a whopping 18 cores and the new Vega 46 graphics card, how does performance compare to one of our iMacs (Retina 5K, 27-inch, Late 2015)?

Firstly, here are specs of the 2 test systems.

iMac vs iMac Pro Specs

Test 1 - VRAY Benchmark 1.07 from Chaosgroup

The first test we did were with V-Ray Benchmark from Chaos Group. V-Ray Benchmark is a stand-alone application to help you test how fast your hardware renders. The benchmark includes two test scenes, one for GPUs and another for CPUs, depending on the processor type you’d like to measure. You can download V-Ray Benchmark for free from Chaos Group.

vray benchmarks

The iMac Pro performs 3.2x faster than the iMac.  This is for the CPU render test. The V-Ray Benchmark GPU test does include Open CL support (required for AMD devices) for benchmarking consistency. V-Ray RT itself does support both Open CL and CUDA.

To view the V-Ray Benchmark leaderboard, check out


Next we tested with MAXON CINEBENCH. CINEBENCH also tests the OpenGL performance, as well as CPU. CPU results using cb units where higher the number, the better the performance.

Figure 3. iMac 27"

Figure 4. iMac Pro

Test 3 - Rendering with Arnold Renderer

To test out the rendering capabilities we set up the Room Interior learning scene from in Maya 2018 and render using Solid Angle's Arnold Renderer.

Figure 5. Room Interior Arnold render

The iMac Pro came out with a significantly lead here rendering the scene approximately 3.6x faster. Note: render time is in minutes:seconds.

Test 4 – Autodesk Flame 2018.3

Autodesk has always recommended higher clock speeds over number of cores due to much of the code not taking advantage of more threads. A faster GPU will always benefit Flame’s performance. We tested using the 2015 3 layer timeline setup built by a flame community member to be used as a benchmark. It comprises of a 250 frame timeline with 3 tracks, based on a ColourFrame Black clip, with BFX/TL effects, and 2 GAP BFX clips that use mostly CCs, transforms, Matchbox shaders, Substance Noise, Action with LensFlare & Rays, Deform, Gmasks and Blurs.

Figure 6. Flame test timeline

Figure 7. Example BFX setup

A normal render will render just the top layer (250 frames). For our benchmark test, we select rendered all 3 layers (total of 750 frames).

Nb. For the testing, internal SSD framestores were used.

Figure 8. Final Render


iMac           Render "Clip" ended: "Speed_Check_2015" in 545.617371 seconds.
iMac Pro    Render "Clip" ended: "Speed_Check_2015" in 391.209961 seconds. 

Here the performance increase is only 30%. With heavier setups, the iMac Pro’s 16GB of VRAM will play a larger part. As mentioned above, the slower CPU clock speed of the iMac Pro might be demonstrating Flame’s lack of multi-core optimisation. Autodesk also recommends the 10 core iMac Pro which has a faster CPU clock speed (3.0 GHz)

If you really require the extra processing power of the iMac Pro and have the budget then its an obvious choice however the cost of the Pro means you will have to really decide if the extra power is worth the expense.

Talk to Digistor to get advice on the best system for your budget and purposes, our technical team can optimise it for your workflow.