Tesla P40: The Best Budget GPU for Local AI
Last updated: December 2025
$7/GB of VRAM. The Tesla P40 offers 24GB for around $170, making it the undisputed king of budget AI builds. Nothing else comes close on $/GB.
Why the P40 Dominates Budget AI
The math is simple:
| GPU | VRAM | Typical Price | $/GB |
|---|---|---|---|
| Tesla P40 | 24GB | $170 | $7.08 |
| Tesla M40 | 24GB | $90 | $3.75 |
| RTX 3060 12GB | 12GB | $200 | $16.67 |
| RTX 3090 | 24GB | $800 | $33.33 |
| RTX 4090 | 24GB | $1,900 | $79.17 |
Yes, the M40 is cheaper per GB, but it's Maxwell architecture — no FP16 support, significantly slower, worse software compatibility. The P40 is Pascal with proper FP16, making it ~2x faster for AI workloads.
The Specs
| VRAM | 24GB GDDR5X |
|---|---|
| Architecture | Pascal (GP102) |
| CUDA Cores | 3840 |
| Memory Bandwidth | 346 GB/s |
| TDP | 250W |
| Compute | 12 TFLOPS FP32, FP16 supported |
| Display Output | None |
| Cooling | Passive (requires airflow) |
| Release | 2016 |
What You Can Run
24GB opens doors that 8-16GB cards can't touch:
- Llama 3.1 8B — Q8 with full 8K context, fast inference
- Qwen 2.5 14B — Q6 or Q8, great quality
- Qwen 2.5 32B — Q4_K_M, excellent quality/performance balance
- Mistral Small 22B — Q5 or Q6, very capable
- Mixtral 8x7B — Q4, runs well with sparse activation
- CodeLlama 34B — Q4_K_M for code generation
For comparison, an RTX 3060 12GB maxes out around 14B models at Q4. The P40's extra 12GB doubles your model capacity.
Real-World Performance
The P40 is not fast. It's 2016 datacenter hardware. But it's usable:
| Model | Quantization | Speed |
|---|---|---|
| Llama 3.1 8B | Q4_K_M | ~25-30 t/s |
| Qwen 2.5 14B | Q4_K_M | ~15-18 t/s |
| Qwen 2.5 32B | Q4_K_M | ~8-10 t/s |
| Llama 3.1 70B | Q2_K (23GB) | ~4-5 t/s |
For reference, an RTX 3090 is roughly 2-3x faster on the same models. But it's also 4-5x the price.
Why Buy a P40
- Unbeatable $/GB — Nothing else offers 24GB under $200
- Runs large models — 32B at Q4, 70B at Q2
- Widely available — eBay is flooded with datacenter pulls
- Pascal architecture — Good software support, FP16 works
- Reliable — Datacenter hardware built for 24/7 operation
- Can buy two — 48GB for ~$350, run 70B at Q4
The Tradeoffs
- No display output — Need a separate GPU for video
- Passive cooling — Requires aftermarket cooler or case fans
- Slow by modern standards — 2-3x slower than RTX 3090
- No tensor cores — No Flash Attention acceleration
- Power hungry — 250W TDP for modest performance
- PCIe 3.0 — Won't bottleneck, but no PCIe 4.0/5.0 benefits
The Cooling Situation
The P40 is a passive heatsink. It was designed for server racks with high-velocity airflow. In a standard PC case, it will throttle and shut down.
Your options:
- GPU cooler shroud — 3D printed shrouds with 92mm blower fan (~$20-30)
- Arctic Accelero — Full replacement cooler (~$50-70)
- Zip-tie fans — Strap 2x 120mm fans to the heatsink (ugly but works)
- Open-air case — Mining frame with good airflow
Budget $30-50 for cooling on top of the card price.
Power Connector Note
The P40 uses an 8-pin EPS/CPU power connector, not a standard PCIe 8-pin. Most PSUs can't power it directly. You'll need:
- A PSU with dual CPU power connectors, or
- A dual 6-pin PCIe to 8-pin EPS adapter (~$10)
P40 vs The Competition
| GPU | VRAM | Speed | Price | Best For |
|---|---|---|---|---|
| P40 | 24GB | Slow | $170 | Budget 24GB builds |
| M40 | 24GB | Very slow | $90 | Extreme budget |
| 3060 12GB | 12GB | Medium | $200 | Consumer card convenience |
| 3090 | 24GB | Fast | $800 | Performance + VRAM |
| A6000 | 48GB | Fast | $2,500 | Maximum VRAM |
Who Should Buy a P40?
Yes, buy a P40 if:
- You want 24GB on a strict budget
- You're comfortable with DIY cooling
- Speed is secondary to model size
- You're building a dedicated inference server
- You want two GPUs for 48GB total (70B models)
Consider something else if:
- You need a daily driver GPU with display output
- Speed matters more than capacity
- You don't want to deal with cooling mods
- 8-16GB is enough for your models
Bottom Line
The Tesla P40 is the best bang-for-buck GPU for local AI if you need 24GB of VRAM and can live with the tradeoffs. Nothing else offers this much memory for this little money.
It's not fast, it's not pretty, and it needs cooling work. But for $170, you can run 32B models that $500+ consumer cards can't touch.
Current P40 Prices
We track Tesla P40 listings from eBay daily. Prices fluctuate — $150-200 is typical for a tested working unit.
Related
- Tesla P100 Review — 16GB HBM2, faster for smaller models at ~$60
- Tesla M40 Review — Even cheaper, significantly slower
- Best GPU for 70B Under $500 — Dual P40 setup
- How we estimate inference speed