If you're still rendering Arnold on CPU, I have some numbers that might change your mind. I tested the same 500-frame Maya character animation - walk cycle with SSS skin, hair groom, and cloth simulation on both Arnold GPU and Arnold CPU on iRender.
If you’re still rendering Arnold on CPU, I have some numbers that might change your mind. I tested the same 500-frame Maya character animation, walk cycle with SSS skin, hair groom, and cloth simulation on both Arnold GPU and Arnold CPU on iRender. Results: Arnold GPU (4× RTX 4090): 6.8 seconds per frame, $0.030/frame, $15.00 total. Arnold CPU (64-core Threadripper Pro): 28.5 seconds per frame, $0.063/frame, $31.50 total. GPU was 4.2× faster and 52% cheaper. The quality was identical, Arnold GPU in version 7.3 supports every shader and feature that CPU does, including SSS, hair, and AOVs.
The only reason I still use Arnold CPU for about 10% of my projects is GarageFarm’s distributed CPU rendering, which can beat iRender’s single-server GPU on speed for large sequences.
| Arnold Mode | Farm | Per Frame | 500 Frames | Wall Time |
|---|---|---|---|---|
| GPU 4× RTX 4090 | iRender | 6.8 sec / $0.030 | $15.00 | 57 min |
| GPU 1× RTX 4090 | iRender | 19.2 sec / $0.044 | $22.00 | 2h 40min |
| CPU 64-core | iRender | 28.5 sec / $0.063 | $31.50 | 3h 58min |
| CPU distributed | GarageFarm | ~$0.052/frame | $26.00 | 22 min |
| CPU distributed | RebusFarm | ~$0.058/frame | $29.00 | 28 min |
When Does Arnold CPU Still Make Sense on Cloud?
Look at that last row in my table – GarageFarm’s distributed Arnold CPU finishes 500 frames in 22 minutes. My iRender GPU took 57 minutes. GarageFarm spreads the frames across 30+ CPU nodes rendering simultaneously, while iRender’s GPU processes frames one-by-one (or a few at a time with multi-GPU). The result: GarageFarm’s CPU is 2.6× faster in wall-clock time even though each individual frame is slower.
For rush deadlines “the client needs the delivery in 2 hours”, GarageFarm’s distributed CPU wins over iRender’s GPU on speed. You pay more per frame ($0.052 vs $0.030), but the 35-minute speed difference can be the difference between meeting and missing a deadline.
The other CPU advantage: 100% shader compatibility. Arnold GPU in version 7.3 covers nearly everything, but a few edge cases remain – certain custom AOVs, some legacy shaders from older Maya scenes, and specific volume rendering configurations render differently or not at all on GPU. Before switching a production pipeline to Arnold GPU, always test a 10-frame batch comparing GPU and CPU output. In my experience, 95% of character animations render identically. The 5% that don’t are usually fixable with minor shader adjustments.
What’s My Recommendation for Maya Animators Using Arnold?
It depends on your situation, and I mean that sincerely; there’s no single right answer. Here’s how I decide for each project:
Use Arnold GPU on iRender if: you’re budget-sensitive (52% cheaper), you have overnight rendering time, your scene uses standard shaders, and you’re comfortable with iRender’s IaaS workflow. This covers about 70% of my Arnold projects.
Use Arnold CPU on GarageFarm if: you need fastest possible delivery (22 min vs 57 min), your scene uses legacy shaders that don’t translate to GPU, or you’re a beginner who wants zero-setup rendering. This covers about 20% of my Arnold projects.
Use Arnold CPU on RebusFarm if: you need 100% frame completion reliability. RebusFarm is the only farm where I’ve had zero failed frames with Arnold CPU across all my tests. If you’re rendering a critical sequence for a studio and can’t afford to re-render failed frames, RebusFarm’s reliability premium is worth it. This covers about 10% of my Arnold projects, the high-stakes ones.
Render Arnold GPU on iRender’s 4× RTX 4090 → View Arnold cloud servers on iRender
FAQ
Is Arnold GPU faster and cheaper than Arnold CPU for animation on cloud?
Yes, 4.2× faster and 52% cheaper per frame on iRender. Arnold GPU (4× RTX 4090): $0.030/frame, 57 minutes for 500 frames. Arnold CPU (64-core): $0.063/frame, nearly 4 hours. Arnold 7.3 supports all major shaders on GPU. Quality is identical for 95% of character animation scenes.
When should I still use Arnold CPU instead of GPU on a render farm?
Three scenarios: GarageFarm distributed CPU for rush deadlines (22 min vs 57 min wall-clock time), scenes with legacy shaders that don’t translate to GPU (~5% of projects), and RebusFarm for critical sequences needing 100% frame reliability. I use GPU for 70% of Arnold projects, GarageFarm CPU for 20%, and RebusFarm for 10%.
How much does Arnold animation cost on a cloud render farm?
Arnold GPU on iRender: $0.030/frame ($15 for 500 frames). Arnold CPU on GarageFarm: $0.052/frame ($26 for 500 frames). Arnold CPU on RebusFarm: $0.058/frame ($29). For Maya animators switching from CPU to GPU on cloud, the cost savings are approximately 38-52% per project with identical visual quality.
You may want to read other articles of mine here.
Image source: Uhr
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