Dual RTX 5090 workstation (2x 32 GB) vs Mac Studio M5 Ultra 256 GB
The Dual RTX 5090 is about 57% faster across 7 like-for-like model configurations; the M5 Ultra has 4× more memory and draws 82% less power under load. Compare model compatibility, like-for-like tokens/sec and ownership cost below.
Dual RTX 5090 workstation (2x 32 GB) · Mac Studio M5 Ultra 256 GB
Verdict
- throughputThe Dual RTX 5090 workstation (2x 32 GB) delivers approximately 57% higher aggregate decode throughput across 7 like-for-like model configurations (same quantization, runtime, context and inference settings).
- capacityBoth machines run all 8 compared models in their best practical configurations. Compare their quantizations and evidence labels before treating any throughput difference as a hardware result.
- costAt 8 hours a day, the Dual RTX 5090 workstation (2x 32 GB) has approximately 12% lower total monthly cost ($80 against $90), for a C corporation in United States (federal).
- powerThe Dual RTX 5090 workstation (2x 32 GB) draws 1180 W under load against 215 W for the Mac Studio M5 Ultra 256 GB — a 5.5× difference that shows up in the electricity line and in how loud and hot the room gets.
- evidenceAll 7 like-for-like throughput rows are estimates. Treat the ranking as indicative and the margins as uncertain.
- recommendationThe Dual RTX 5090 workstation (2x 32 GB) is both faster and cheaper to own here, so it is the straightforward choice unless you need something specific to the Mac Studio M5 Ultra 256 GB.
Hardware
| Dual RTX 5090 workstation (2x 32 GB) | Mac Studio M5 Ultra 256 GB | |
|---|---|---|
| Purchase price estimate | $5,854 * | $8,647 * |
| Memory | 64 GB | 256 GB |
| Theoretical bandwidth (aggregate on multi-GPU) | 3,584 GB/s | 1,200 GB/s |
| Usable bandwidth indicator | interconnect-adjusted per workload | 1,052 GB/s (88%) |
| Nominal power | 1400 W | 300 W |
| Measured load power | 1180 W | 215 W |
| Idle power | 110 W | 13 W |
| Architecture | 2× GPU | unified memory |
Like-for-like performance7 comparable models
Ternary Bonsai 2 27BNemotron 3.5 Lightning 30B-A3BQwen3-Coder 30B-A3BQwen3 30B-A3BGemma 4 26B-A4Bgpt-oss-20bLlama 3.3 70BDeepSeek-R1-Distill 32B
| Model | Dual RTX 5090 workstation (2x 32 GB) | Mac Studio M5 Ultra 256 GB | Winner |
|---|---|---|---|
| Ternary Bonsai 2 27B 27.36B | — no matched configuration | — no matched configuration | Not comparable |
| Nemotron 3.5 Lightning 30B-A3B 31.578B (3B active) | ~249–359 t/s Q8_0 | ~180–258 t/s Q8_0 | Dual RTX 5090 workstation (2x 32 GB) +39% estimated · estimator_v1 · 8K context |
| Qwen3-Coder 30B-A3B 30.532B (3.3B active) | ~236–339 t/s Q8_0 | ~167–240 t/s Q8_0 | Dual RTX 5090 workstation (2x 32 GB) +42% estimated · estimator_v1 · 8K context |
| Qwen3 30B-A3B 30.532B (3.3B active) | ~236–339 t/s Q8_0 | ~167–240 t/s Q8_0 | Dual RTX 5090 workstation (2x 32 GB) +42% estimated · estimator_v1 · 8K context |
| Gemma 4 26B-A4B 25.806B (3.8B active) | ~139–200 t/s BF16 | ~86.3–124 t/s BF16 | Dual RTX 5090 workstation (2x 32 GB) +61% estimated · estimator_v1 · 8K context |
| gpt-oss-20b 20.915B (3.6B active) | ~145–208 t/s BF16 | ~90.6–130 t/s BF16 | Dual RTX 5090 workstation (2x 32 GB) +60% estimated · estimator_v1 · 8K context |
| Llama 3.3 70B 70.554B | ~30.8–44.3 t/s Q5_K_M | ~16.8–24.2 t/s Q5_K_M | Dual RTX 5090 workstation (2x 32 GB) +83% estimated · estimator_v1 · 8K context |
| DeepSeek-R1-Distill 32B 32.764B | ~43.3–62.3 t/s Q8_0 | ~24–34.6 t/s Q8_0 | Dual RTX 5090 workstation (2x 32 GB) +80% estimated · estimator_v1 · 8K context |
Hardware deltas are calculated only when quantization, runtime, exact context, execution/decode mode and relevant inference settings match. Measured and estimated results are never compared to each other. A difference under 10% is reported as a tie.
Best practical configuration
| Model | Dual RTX 5090 workstation (2x 32 GB) | Mac Studio M5 Ultra 256 GB | Practical result |
|---|---|---|---|
| Ternary Bonsai 2 27B | — PTQ1_0 · estimated | — PTQ1_0 · estimated | Both fit; configurations may differ |
| Nemotron 3.5 Lightning 30B-A3B | ~249–359 t/s Q8_0 · estimated | ~180–258 t/s Q8_0 · estimated | Both fit; configurations may differ |
| Qwen3-Coder 30B-A3B | ~236–339 t/s Q8_0 · estimated | ~167–240 t/s Q8_0 · estimated | Both fit; configurations may differ |
| Qwen3 30B-A3B | ~236–339 t/s Q8_0 · estimated | ~167–240 t/s Q8_0 · estimated | Both fit; configurations may differ |
| Gemma 4 26B-A4B | ~216–311 t/s Q8_0 · estimated | ~149–214 t/s Q8_0 · estimated | Both fit; configurations may differ |
| gpt-oss-20b | ~324–466 t/s MXFP4 · estimated | ~261–376 t/s MXFP4 · estimated | Both fit; configurations may differ |
| Llama 3.3 70B | ~35.8–51.5 t/s Q4_K_M · estimated | ~11.3–16.3 t/s Q8_0 · estimated | Both fit; configurations may differ |
| DeepSeek-R1-Distill 32B | ~43.3–62.3 t/s Q8_0 · estimated | ~24–34.6 t/s Q8_0 · estimated | Both fit; configurations may differ |
This is a deployment comparison: each machine uses its own recommended configuration. Different quantizations can change speed and quality, so these figures are not raw hardware benchmarks.
Economics — United States (federal), C corporation, 8h/day
| Dual RTX 5090 workstation (2x 32 GB) | Mac Studio M5 Ultra 256 GB | |
|---|---|---|
| Purchase price estimate | $5,854 | $8,647 |
| Reclaimable VAT | $0 | $0 |
| Net cash at purchase | $5,854 | $8,647 |
| Monthly depreciation | $82.94 | $100.88 |
| Monthly electricity | $7.98 (57 kWh) | $1.32 (9 kWh) |
| Tax programme | §179 100.0% | §179 100.0% |
| Tax-programme benefit | $1,229 | $1,816 |
| Monthly economic cost | $79.98 | $90.39 |
| Total over 5 years | $4,799 | $5,424 |
Purchase prices are localized inputs in USD: tax/VAT excluded for Dual RTX 5090 workstation (2x 32 GB) and tax/VAT excluded for Mac Studio M5 Ultra 256 GB. Net cash and monthly economic cost then apply the selected United States (federal) / C corporation tax treatment. Tax assumptions last verified 2026-09-07. Federal planning estimate only, not tax advice. State and local income tax, sales/use tax and incentives are excluded. It assumes 100% business use, a Section 179 election, enough business income to use it, and that the full annual limit remains available.