Dual RTX 5090 workstation (2x 32 GB) vs Quad RTX 5090 workstation (4x 32 GB)
Dual RTX 5090 workstation (2x 32 GB) · Quad RTX 5090 workstation (4x 32 GB)
Verdict
- throughputThe Quad RTX 5090 workstation (4x 32 GB) delivers approximately 28% higher aggregate decode throughput across the 8 models both machines can run (geometric mean of the per-model ratios).
- capacityBoth machines run all 8 compared models, so this is a pure speed and cost decision rather than a capability one.
- costAt 8 hours a day, the Dual RTX 5090 workstation (2x 32 GB) has approximately 53% lower total monthly cost (€80 against €170), for a C corporation in United States (federal).
- powerThe Quad RTX 5090 workstation (4x 32 GB) draws 2250 W under load against 1180 W for the Dual RTX 5090 workstation (2x 32 GB) — a 1.9× difference that shows up in the electricity line and in how loud and hot the room gets.
- evidenceEvery throughput figure in this comparison is estimated. Treat the ranking as indicative and the margins as unreliable.
- recommendationThere is no single answer: the Quad RTX 5090 workstation (4x 32 GB) is faster, the Dual RTX 5090 workstation (2x 32 GB) is cheaper to own, and the Dual RTX 5090 workstation (2x 32 GB) gives more throughput per euro of purchase price. Pick on whichever constraint actually binds you — interactive latency, monthly budget, or capacity headroom for larger models later.
Every statement above is generated from the calculations on this page by fixed rules — no prose is written for individual comparisons. If the numbers change, the verdict changes with them.
Hardware
| Dual RTX 5090 workstation (2x 32 GB) | Quad RTX 5090 workstation (4x 32 GB) | |
|---|---|---|
| Price (NL, incl. VAT) | €5.854 | €12.611 |
| Memory | 64 GB | 128 GB |
| Memory bandwidth | 3,584 GB/s | 7,168 GB/s |
| Achieved bandwidth | 2,838 GB/s (79%) | 5,675 GB/s (79%) |
| Nominal power | 1400 W | 2600 W |
| Measured load power | 1180 W | 2250 W |
| Idle power | 110 W | 190 W |
| Architecture | 2× GPU | 4× GPU |
Model performance8 models run on both
Qwen3-Coder 30B-A3BQwen3 30B-A3BGemma 4 26B-A4Bgpt-oss-20bLlama 3.3 70BDeepSeek-R1-Distill 32BQwen3 32BGemma 4 31B
| Model | Dual RTX 5090 workstation (2x 32 GB) | Quad RTX 5090 workstation (4x 32 GB) | Winner |
|---|---|---|---|
| Qwen3-Coder 30B-A3B 30.532B (3.3B active) | ~236–339 t/s Q8_0 | ~301–434 t/s Q8_0 | Quad RTX 5090 workstation (4x 32 GB) +22% |
| Qwen3 30B-A3B 30.532B (3.3B active) | ~236–339 t/s Q8_0 | ~301–434 t/s Q8_0 | Quad RTX 5090 workstation (4x 32 GB) +22% |
| Gemma 4 26B-A4B 25.806B (3.8B active) | ~216–311 t/s Q8_0 | ~281–404 t/s Q8_0 | Quad RTX 5090 workstation (4x 32 GB) +23% |
| gpt-oss-20b 20.915B (3.6B active) | ~324–466 t/s MXFP4 | ~387–556 t/s MXFP4 | Quad RTX 5090 workstation (4x 32 GB) +16% |
| Llama 3.3 70B 70.554B | ~38.4–55.2 t/s MLX 4-bit | ~32.3–46.4 t/s Q8_0 | Dual RTX 5090 workstation (2x 32 GB) +19% |
| DeepSeek-R1-Distill 32B 32.764B | ~43.3–62.3 t/s Q8_0 | ~65.3–94 t/s Q8_0 | Quad RTX 5090 workstation (4x 32 GB) +34% |
| Qwen3 32B 32.762B | ~43.3–62.4 t/s Q8_0 | ~65.3–94 t/s Q8_0 | Quad RTX 5090 workstation (4x 32 GB) +34% |
| Gemma 4 31B 31.273B | ~45.2–65.1 t/s Q8_0 | ~68.1–98 t/s Q8_0 | Quad RTX 5090 workstation (4x 32 GB) +34% |
Differences under 10% are reported as a tie: they are smaller than the spread between published benchmarks of the same configuration, so calling a winner would be false precision. Rows where a model fits on only one machine are decided by capacity, not speed.
Economics — United States (federal), C corporation, 8h/day
| Dual RTX 5090 workstation (2x 32 GB) | Quad RTX 5090 workstation (4x 32 GB) | |
|---|---|---|
| Purchase price estimate | $5,854 | $12,611 |
| Reclaimable VAT | $0 | $0 |
| Net cash at purchase | $5,854 | $12,611 |
| Monthly depreciation | $82.94 | $178.65 |
| Monthly electricity | $7.98 (57 kWh) | $14.83 (106 kWh) |
| Tax programme | §179 100.0% | §179 100.0% |
| Tax-programme benefit | $1,229 | $2,648 |
| Monthly economic cost | $79.98 | $170.40 |
| Total over 5 years | $4,799 | $10,224 |
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.