RTX 3090 Ti vs RTX 3080
Both run on the same nodes, the same templates and the same tiers here — so the choice comes down to memory, bandwidth and price. Every figure below is from the catalogue or the vendor datasheet.
- RTX 3090 Ti
- $0.06/h24 GB · Ampere · 24 available
- RTX 3080
- $0.03/h10 GB · Ampere · 64 available
- Price gap
- 50%On spot, per GPU-hour
- Over 100 h
- $3.00Difference for the same GPU-hours
What actually separates them.
Four differences that change a decision, computed from the numbers rather than asserted.
Bigger models fit on the RTX 3090 Ti
24 GB against 10 GB. At FP16 that is about 9B parameters on one GPU, against 4B.
The RTX 3080 costs 50% less per hour
$0.03 against $0.06 on spot — $3.00 of difference over 100 GPU-hours.
Token generation is faster on the RTX 3090 Ti
1,008 GB/s against 760 GB/s. Inference reads the whole model from memory for every token, so bandwidth, not FLOPS, usually sets the ceiling.
More memory per dollar on the RTX 3090 Ti
400 GB per dollar per hour against 333 GB. The usual tie-breaker when both cards fit the job.
Every figure we hold on both cards.
A row is marked only when both values exist and one is genuinely better. RTX 3090 Ti leads on 6 rows, RTX 3080 on 4.
| RTX 3090 Ti | RTX 3080 | |
|---|---|---|
| GPU memoryDecides which models fit at all | 24 GB GDDR6X | 10 GB GDDR6X |
| Memory bandwidthSets token throughput on inference | 1,008 GB/s | 760 GB/s |
| FP32 | 40 TFLOPS | 30 TFLOPS |
| 8-bit float (FP8)Halves the memory a model needs, where the stack supports it | Not supported | Not supported |
| Architecture | Ampere (2022) | Ampere (2020) |
| Board powerLower is cheaper to run at scale — for us, not for your bill | 450 W | 320 W |
| GPU-to-GPU linkOnly matters for multi-GPU training | NVLink | PCIe only |
| Node sizes | 1×, 2×, 4× | 1×, 2×, 4× |
| Spot price | $0.06/h | $0.03/h |
| On-demand price | $0.09/h | $0.06/h |
| Memory per dollarGPU memory per $1 of spot time, per hour | 400 GB | 333 GB |
| 30-day reclaim rateShare of spot instances reclaimed | 10–15% | 15–20% |
| Available now | 24 GPUs | 64 GPUs |
Specifications come from each vendor's datasheet — linked on the RTX 3090 Ti page and the RTX 3080 page. Prices are ours, per GPU-hour, billed per minute.
The same models, on one GPU of each.
Weights only, with 20% of the memory kept free for activations and the KV cache. A cross means one GPU is not enough — the model page has the multi-GPU arithmetic.
| Model | Precision | RTX 3090 Ti 24 GB | RTX 3080 10 GB |
|---|---|---|---|
| Llama 3.1 8B8B parameters | FP16 · 16 GB | Fits | Needs 2× node |
| INT4 · 4 GB | Fits | Fits | |
| Qwen2.5 32B32B parameters | FP16 · 64 GB | Needs 4× node | Needs more than one node |
| INT4 · 16 GB | Fits | Needs 2× node | |
| Llama 3.3 70B70B parameters | FP16 · 140 GB | Needs more than one node | Needs more than one node |
| INT4 · 35 GB | Needs 2× node | Needs more than one node | |
| Mixtral 8x22B141B parameters | FP16 · 282 GB | Needs more than one node | Needs more than one node |
| INT4 · 71 GB | Needs 4× node | Needs more than one node |
The same 100 GPU-hours on each.
Compute only, billed per minute. Storage is $0.08 per GB-month on either card.
| RTX 3090 Ti | RTX 3080 | |
|---|---|---|
| One hour, spot | $0.06 | $0.03 |
| One day, spot | $1.44 | $0.72 |
| 100 GPU-hours, spot | $6.00 | $3.00 |
| 100 GPU-hours, on-demand | $9.00 | $6.00 |
| A month, reserved | $43.80 | $29.20 |
Take the RTX 3090 Ti when…
- Fine-tuning small models — LoRA on 7B–13B models, and full fine-tuning below 3B.
- Image and video generation — Diffusion pipelines run entirely in memory at this capacity.
- Multi-GPU jobs over NVLink — GPU-to-GPU traffic stays off the PCIe bus, which is what makes tensor and pipeline parallelism worth it.
Take the RTX 3080 when…
- Quantised inference — Small and medium models in 4-bit or 8-bit form, with the whole model resident in memory.
- Computer vision and batch jobs — Detection, classification, embeddings and transcoding at a very low hourly rate.
- Anything that can checkpoint — On the spot tier this model is 50% below its own on-demand price, with a 2-minute notice before a reclaim.
RTX 3090 Ti or RTX 3080?
Which is cheaper, the RTX 3090 Ti or the RTX 3080?
The RTX 3080, at $0.03 per GPU-hour on spot against $0.06 — 50% less. On-demand: $0.06 against $0.09.
Which one should I take for inference?
Take the one that holds the model with room for the KV cache, then the one with more memory bandwidth. Here that is the RTX 3090 Ti on capacity (24 GB) and the RTX 3090 Ti on bandwidth.
Can I run both on the same job?
Not inside one instance — a node holds GPUs of a single model. You can run two instances in parallel, on the same persistent volume in turn, or split the work: a big card for the model that needs capacity, a cheap one for the parts that do not.
Other comparisons: the full list · all 47 models
Try both for less than the price of deciding.
An hour on each costs $0.09 on spot. Nothing renews, and your disk moves between them.
Billed per minute from the moment the instance is reachable. Minimum credit $40, no subscription.