Table of Contents
Overview
The RTX 3090 was NVIDIA's flagship consumer GPU in 2020. Three years later, it's available used for $600-800 — making it one of the best value GPUs for AI workloads and passive income. But how does it compare to the RTX 4090?
RTX 3090
- • Ampere Architecture (2020)
- • 24GB GDDR6X
- • 10,496 CUDA Cores
- • $600-800 used
RTX 4090
- • Ada Lovelace Architecture (2022)
- • 24GB GDDR6X
- • 16,384 CUDA Cores
- • $1,400-1,600 used
The Value Proposition
At $600-800 used, the RTX 3090 offers 24GB VRAM (same as 4090) at half the price. For AI workloads limited by VRAM rather than compute speed, it's an incredible deal.
Specifications Comparison
| Specification | RTX 3090 | RTX 4090 |
|---|---|---|
| Architecture | Ampere | Ada Lovelace |
| CUDA Cores | 10,496 | 16,384 |
| VRAM | 24GB GDDR6X | 24GB GDDR6X |
| Memory Bus | 384-bit | 384-bit |
| Memory Bandwidth | 936 GB/s | 1,008 GB/s |
| TDP | 350W | 450W |
| Base Clock | 1.40 GHz | 2.23 GHz |
| Boost Clock | 1.70 GHz | 2.52 GHz |
| RT Cores | 2nd Gen | 3rd Gen |
| Tensor Cores | 3rd Gen | 4th Gen |
| MSRP (Launch) | $1,499 | $1,599 |
| Used Price (2025) | $600-800 | $1,400-1,600 |
AI & Deep Learning Performance
The RTX 4090 is significantly faster for AI workloads, but the 3090's 24GB VRAM means it can still run the same large models — just slower.
| Task | RTX 3090 | RTX 4090 | 4090 Advantage |
|---|---|---|---|
| LLM Training (7B) | ~90 min | ~70 min | +29% |
| Stable Diffusion XL | 0.9 img/s | 1.4 img/s | +56% |
| LLM Inference (13B) | 18 tok/s | 24 tok/s | +33% |
| PyTorch FP16 | ~560 TFLOPS | ~1,300 TFLOPS | +132% |
| Tensor Core FP8 | N/A | ~2,600 TFLOPS | New |
FP8 Tensor Cores
The RTX 4090 supports FP8 precision for AI inference, which the 3090 lacks. This matters for running quantized LLMs at maximum speed, but many workloads still use FP16 where the 3090 performs well.
Gaming Performance
For gaming, the RTX 4090 is significantly faster — especially with DLSS 3 Frame Generation. The 3090 is still excellent for 1440p gaming but struggles with 4K ray tracing in demanding titles.
| Game (4K Ultra) | RTX 3090 | RTX 4090 | Gain |
|---|---|---|---|
| Cyberpunk 2077 4K | 55 FPS | 95 FPS | +73% |
| Alan Wake 2 4K RT | 28 FPS | 55 FPS | +96% |
| Black Myth: Wukong 4K | 45 FPS | 80 FPS | +78% |
| Hogwarts Legacy 4K | 55 FPS | 95 FPS | +73% |
| Flight Simulator 4K | 40 FPS | 65 FPS | +63% |
Passive Income Potential
Both GPUs can earn passive income through Griddly Hub. The 3090 has a faster ROI due to its lower purchase price, despite earning less per month.
| Metric | RTX 3090 | RTX 4090 |
|---|---|---|
| Griddly Hub Earnings | $80-120/month | $120-180/month |
| Power Consumption | ~350W | ~450W |
| Electricity Cost (US avg) | ~$38/month | ~$49/month |
| Net Profit | $42-82/month | $71-131/month |
| ROI (used price) | 8-14 months | 11-20 months |
Best ROI: RTX 3090
At $600-800 used, the RTX 3090 pays for itself in 8-14 months. The 4090 takes 11-20 months despite higher earnings. For passive income, the 3090 wins.
Value Analysis
Pros
- Incredible value at $600-800 used
- Same 24GB VRAM as 4090
- Lower power consumption (350W)
- Faster ROI for passive income
- Great for AI on a budget
Cons
- No FP8 Tensor Core support
- Older Ampere architecture
- Slower in modern games
- No DLSS 3 Frame Generation
- End of driver support coming
Pros
- 2x faster in AI workloads
- DLSS 3 Frame Generation
- FP8 Tensor Core support
- Better for latest games
- Longer driver support
Cons
- 2x the price of used 3090
- Higher power consumption (450W)
- Slower ROI for passive income
- Overkill for many workloads
- Being replaced by 5090
Which Should You Buy?
Buy RTX 3090 if:
- • You want the best value for AI workloads
- • Passive income ROI is your priority
- • You're on a budget under $1,000
- • 24GB VRAM matters more than speed
- • You game at 1440p or don't need 4K
Buy RTX 4090 if:
- • You need maximum AI performance
- • You game at 4K with ray tracing
- • DLSS 3 Frame Generation matters to you
- • You want longer driver support
- • Budget isn't a primary concern