The RTX 4090 is a high-performance Inferred GPU.
Recommended Scenarios
Deep Learning
Model Inference
Video Encoding
Architecture
N/A
What Users Say
Real experiences from ML engineers and researchers
Inference and small-scale trainingReddit
"4090s are the best kept secret in cloud ML. At $0.40-0.60/hr, you get A100-level inference performance for 1/3 the price. Trained a 7B model on 2x4090 for $50 total. Sure, no NVLink and only 24GB VRAM, but for small-to-medium models? Absolutely unbeatable value."
Mixed prototyping and productionHacker News
"4090 consumer cards in data centers is... weird. They work great until they don't. Had one die mid-training, provider replaced it in 2 hours but still lost work. No ECC memory means you might get silent errors on long training runs. For prototyping? Perfect. For production? Use A100s."
Side projects and LoRA trainingTwitter
"Running a 4090 on Vast.ai for $0.35/hr. It's literally cheaper than my coffee habit. Fine-tuned a LoRA on my custom dataset for under $5. The catch? You need to be comfortable with spot interruptions. For experimentation and side projects, 4090s democratize access to serious compute."
Running inference API serviceReddit
"24GB is the limitation everyone mentions, but it's worse than that — you really only get ~21GB usable after CUDA overhead. Can't even fit Llama 70B in 4-bit without offloading. But for 7B-13B models? Sweet spot. I run inference APIs on 4090s and the price/perf is insane."
Personal research clusterDiscord
"Got 8x4090 on a mining rig repurposing site for $2.80/hr total. Set up my own little training cluster. The lack of NVLink hurts — distributed training is slower than it should be. But for embarrassingly parallel workloads (like hyperparameter sweeps), it's incredible value."