Best Render Farm for V-Ray GPU vs CPU: Which Is Faster for Architecture?
V-Ray GPU is 2–3× faster than V-Ray CPU for most architectural scenes on cloud render farms. On iRender’s RTX 4090 (24GB VRAM), a 4K arch-viz interior renders in 10–30 minutes. The same scene on a 32-core Threadripper Pro CPU takes 25–75 minutes. However, V-Ray CPU handles extreme polygon counts (100+ million polygons) and memory-intensive scenes more reliably — it uses system RAM (256GB on iRender) instead of GPU VRAM (24GB), which overflows on extremely detailed urban models. For 90% of architectural work, GPU is the recommended choice on cloud. CPU is better for the 10% of scenes that exceed 24GB VRAM.
| Factor | V-Ray GPU (RTX 4090) | V-Ray CPU (32-core) |
| 4K Interior Still | 10–30 min | 25–75 min |
| 4K Exterior Still | 20–45 min | 45–120 min |
| Memory Limit | 24GB VRAM (hard ceiling) | 256GB RAM (virtually unlimited) |
| Max Polygon Count | ~50–80M polygons | 500M+ polygons |
| Multi-Device Scaling | 2–8 GPUs (85–95% efficiency) | Multi-node via SaaS farms |
| iRender Pricing | ~$8.20/hr (single GPU) | ~$8.20/hr (Threadripper Pro) |
| SaaS Farm Support | ✅ RebusFarm, GarageFarm | ✅ RebusFarm, GarageFarm |
When Should Architects Choose V-Ray GPU on Cloud?
Choose GPU for: standard residential and commercial interiors (under 50 million polygons), exterior scenes with moderate vegetation, and any project where speed matters more than memory capacity. GPU’s advantage is pure render speed — the RTX 4090’s thousands of CUDA cores process ray tracing calculations approximately 2–3× faster than even high-end CPUs for typical arch-viz scenes.
On iRender, GPU rendering also enables interactive rendering — V-Ray’s GPU Interactive mode updates the preview in near real-time as you adjust materials and lighting, making it ideal for design iteration sessions. CPU rendering does not offer this interactive feedback loop.
When Does V-Ray CPU Actually Beat GPU on Cloud?
CPU wins in three specific scenarios: (1) Extreme polygon counts — urban masterplans with 100–500+ million polygons exceed the RTX 4090’s 24GB VRAM, causing V-Ray GPU to crash. CPU uses system RAM (256GB on iRender), handling these scenes without memory issues. (2) Heavy displacement mapping — detailed stone, brick, and terrain textures that generate geometry at render time can spike VRAM usage unpredictably. (3) Scenes with many V-Ray proxies — Forest Pack forests with millions of individual plants occasionally overwhelm GPU VRAM despite V-Ray’s out-of-core optimizations.
For SaaS farms (RebusFarm, GarageFarm), both GPU and CPU rendering are supported. GarageFarm’s automatic scene analysis can recommend whether your specific scene will render faster on GPU or CPU nodes — a useful feature for studios unsure which to choose.
See more: Render V-Ray GPU or CPU on cloud → Render V-Ray GPU or CPU on cloud → Compare V-Ray GPU and CPU servers on iRender
Frequently Asked Questions
- Can I switch between V-Ray GPU and CPU rendering on the same iRender server?
Yes. iRender’s servers have both an RTX 4090 GPU and a Threadripper Pro CPU. You switch between V-Ray GPU and CPU modes within V-Ray’s render settings — no server change needed. A practical workflow: start with GPU Interactive mode for design iteration, then switch to CPU mode if a specific scene exceeds 24GB VRAM. Both render at $8.20/hour on the same server.
2. Is V-Ray GPU or CPU cheaper per image on a cloud render farm?
GPU is typically cheaper because it renders faster. A 4K interior costing $1.40–4.10 on GPU (10–30 min) would cost $3.40–10.25 on CPU (25–75 min) at the same $8.20/hour rate. On SaaS farms with per-frame pricing, GPU nodes are also generally cheaper per frame because the farm completes each frame faster. The exception: if your scene crashes on GPU (VRAM overflow), CPU is the only option regardless of cost.
3. Does V-Ray GPU produce identical image quality to V-Ray CPU?
Nearly identical. Since V-Ray 5, GPU and CPU modes use the same rendering engine and produce visually indistinguishable output for architectural scenes. Minor differences may appear in very specific edge cases (certain volumetric effects, some legacy material types), but for practical arch-viz work, the quality is the same. The choice between GPU and CPU should be based purely on speed and memory requirements, not image quality.
Related post: Best Render Farm for V-Ray Architecture: GPU Cloud Rendering for Arch-Viz Studios
