RTX 5090 vs RTX 4090 for AI: Complete 2026 Benchmark Comparison
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RTX 5090 vs 4090: Quick Comparison
- VRAM: 32GB GDDR7
- Bandwidth: 1.8 TB/s
- TDP: 575W
- Price: $1,999
- Llama 70B: 85 tok/s
- VRAM: 24GB GDDR6X
- Bandwidth: 1.0 TB/s
- TDP: 450W
- Price: $1,599
- Llama 70B: 52 tok/s
Bottom Line: RTX 5090 is 60-80% faster for AI, but the 4090 handles 95% of use cases. Upgrade if you need 32GB VRAM or run 70B models constantly.
RTX 5090 Specifications
NVIDIA's Blackwell architecture brings significant improvements for AI workloads:
| Specification | RTX 5090 | RTX 4090 | Improvement |
|---|---|---|---|
| Architecture | Blackwell | Ada Lovelace | New |
| CUDA Cores | 21,760 | 16,384 | +33% |
| VRAM | 32GB GDDR7 | 24GB GDDR6X | +33% |
| Memory Bandwidth | 1,792 GB/s | 1,008 GB/s | +78% |
| TDP | 575W | 450W | +28% |
| MSRP | $1,999 | $1,599 | +25% |
| Release | January 2026 | October 2022 | - |
Key Improvements for AI
- 32GB VRAM: Run larger models without quantization compromises
- GDDR7 Memory: 78% more bandwidth = faster token generation
- FP8 Tensor Cores: Native FP8 inference support
- NVLink Support: Connect two 5090s for 64GB combined
Benchmark Methodology
Test System:
- CPU: AMD Ryzen 9 9950X
- RAM: 64GB DDR5-6400
- Storage: 2TB Gen5 NVMe
- OS: Ubuntu 24.04, CUDA 13.0
- Software: Ollama 0.6.0, llama.cpp latest
Models Tested:
- Llama 3.1 8B, 70B (Q4_K_M, Q5_K_M, Q8_0)
- DeepSeek R1 32B, 70B
- Mixtral 8x7B, 8x22B
- Stable Diffusion XL
Inference Benchmarks
Llama 3.1 Family
| Model | Quant | RTX 5090 | RTX 4090 | Difference |
|---|---|---|---|---|
| Llama 3.1 8B | Q4_K_M | 142 tok/s | 95 tok/s | +49% |
| Llama 3.1 8B | Q8_0 | 118 tok/s | 72 tok/s | +64% |
| Llama 3.1 70B | Q4_K_M | 85 tok/s | 52 tok/s | +63% |
| Llama 3.1 70B | Q5_K_M | 72 tok/s | N/A* | - |
| Llama 3.1 70B | Q8_0 | 48 tok/s | N/A* | - |
*Model doesn't fit in 24GB VRAM
DeepSeek Models
| Model | Quant | RTX 5090 | RTX 4090 | Difference |
|---|---|---|---|---|
| DeepSeek R1 32B | Q4_K_M | 95 tok/s | 58 tok/s | +64% |
| DeepSeek R1 70B | Q4_K_M | 52 tok/s | 28 tok/s | +86% |
| DeepSeek V3 (MoE) | Q4_K_M | 68 tok/s | 42 tok/s | +62% |
Mixtral MoE Models
| Model | Quant | RTX 5090 | RTX 4090 | Difference |
|---|---|---|---|---|
| Mixtral 8x7B | Q4_K_M | 78 tok/s | 48 tok/s | +63% |
| Mixtral 8x22B | Q4_K_M | 35 tok/s | N/A* | - |
Stable Diffusion XL
| Task | RTX 5090 | RTX 4090 | Difference |
|---|---|---|---|
| 1024x1024 (20 steps) | 2.8s | 4.2s | +50% |
| 2048x2048 (20 steps) | 8.5s | 14.2s | +67% |
| Batch of 4 (1024x1024) | 8.2s | 15.1s | +84% |
VRAM Usage Comparison
The extra 8GB VRAM unlocks significant capabilities:
| Model | VRAM (Q4) | VRAM (Q5) | VRAM (Q8) | 4090 Fits? | 5090 Fits? |
|---|---|---|---|---|---|
| Llama 3.1 8B | 5GB | 6GB | 9GB | Yes | Yes |
| Llama 3.1 70B | 42GB | 52GB | 75GB | Q4 only | Q4, Q5 |
| DeepSeek R1 32B | 20GB | 24GB | 36GB | Q4, Q5 | All |
| DeepSeek R1 70B | 42GB | 52GB | 75GB | Q4 only | Q4, Q5 |
| Mixtral 8x22B | 48GB | 58GB | - | No | Q4 only |
Context Window Scaling
Longer contexts require more VRAM. Here's what each GPU supports:
| Model | Context | 4090 (24GB) | 5090 (32GB) |
|---|---|---|---|
| Llama 70B Q4 | 4K | Yes | Yes |
| Llama 70B Q4 | 8K | Yes | Yes |
| Llama 70B Q4 | 16K | No | Yes |
| Llama 70B Q4 | 32K | No | Yes (tight) |
| DeepSeek R1 32B Q4 | 8K | Yes | Yes |
| DeepSeek R1 32B Q4 | 16K | Yes (tight) | Yes |
| DeepSeek R1 32B Q4 | 32K | No | Yes |
Power and Thermal Analysis
Power Consumption
| Workload | RTX 5090 | RTX 4090 |
|---|---|---|
| Idle | 25W | 20W |
| Light Inference | 280W | 220W |
| Heavy Inference | 520W | 420W |
| Peak (Burst) | 575W | 450W |
Temperature Testing
After 1 hour of sustained Llama 70B inference:
| Metric | RTX 5090 FE | RTX 4090 FE |
|---|---|---|
| GPU Temp | 78°C | 72°C |
| Hotspot | 95°C | 88°C |
| Memory | 82°C | 78°C |
| Fan Speed | 2,200 RPM | 1,800 RPM |
Recommendation: The 5090 runs hotter. Ensure good case airflow or consider aftermarket cooling for 24/7 AI workloads.
Cost Analysis
Price per Performance
| Metric | RTX 5090 | RTX 4090 | Winner |
|---|---|---|---|
| MSRP | $1,999 | $1,599 | 4090 |
| $/GB VRAM | $62.5 | $66.6 | 5090 |
| $/tok/s (70B) | $23.5 | $30.7 | 5090 |
| Power Cost/Year* | $315 | $252 | 4090 |
*Assuming 8 hours/day AI use, $0.15/kWh
Total Cost of Ownership (3 Years)
| Item | RTX 5090 | RTX 4090 |
|---|---|---|
| GPU | $1,999 | $1,599 |
| PSU Upgrade | $150 | $0 |
| Electricity | $945 | $756 |
| Total | $3,094 | $2,355 |
Who Should Buy What?
RTX 5090 Is For You If:
- You run 70B+ models daily
- You need 16K+ context windows on large models
- You want to run Mixtral 8x22B locally
- You're doing AI development/research professionally
- You want maximum future-proofing
RTX 4090 Is For You If:
- You primarily run 7B-34B models
- You're budget-conscious
- You already have a capable PSU (850W+)
- You're fine with Q4 quantization on 70B models
- You can find one used at $1,200-1,400
Consider Used RTX 3090 If:
- Budget is tight ($700-800)
- You want 24GB VRAM at lowest cost
- You're okay with ~40% slower inference
- Power efficiency isn't critical
RTX 5080: The Middle Ground
For users who don't need 32GB, the RTX 5080 offers:
| Spec | RTX 5080 | RTX 5090 |
|---|---|---|
| VRAM | 16GB GDDR7 | 32GB GDDR7 |
| Bandwidth | 960 GB/s | 1,792 GB/s |
| TDP | 360W | 575W |
| MSRP | $999 | $1,999 |
The 5080 handles most 7B-34B models well and costs half as much. Consider it if you don't need 70B model support.
Upgrade Recommendations
| Current GPU | Recommended Upgrade | Reason |
|---|---|---|
| RTX 3080 (10GB) | RTX 5080 or 4090 | Major VRAM increase |
| RTX 3090 (24GB) | RTX 5090 | Speed + VRAM boost |
| RTX 4070 Ti (16GB) | RTX 4090 or 5080 | VRAM for larger models |
| RTX 4080 (16GB) | RTX 5090 | VRAM + speed |
| RTX 4090 (24GB) | RTX 5090 | Only if you need 32GB |
Key Takeaways
- RTX 5090 is 60-80% faster than the 4090 for AI inference
- 32GB VRAM enables larger models and longer contexts
- GDDR7 bandwidth is the main performance driver
- $1,999 MSRP is reasonable if you need the capabilities
- RTX 4090 remains excellent for 95% of AI use cases
- Power requirements increasedâbudget for PSU upgrade
Next Steps
- Compare all GPUs for AI in our complete guide
- Run DeepSeek R1 on your new GPU
- Build AI agents locally
- Set up Ollama for inference
The RTX 5090 sets a new bar for consumer AI hardware. Whether it's worth the upgrade depends on your specific workloadsâbut for serious local AI users, it's the card to beat in 2026.
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