Comparison · The cheap fast card against the data-centre one

# RTX 4090 or A100 PCIe?

Both are dedicated, both are monthly, both open without an identity check. What separates them is memory, bandwidth and $199 a month — and which of those matters depends entirely on what you intend to run.

- $193/mo RTX 4090, one card
- $392/mo A100 PCIe, one card
- 24 vs 40 GB memory per card
- 1.5× bandwidth gap

## The short answer

Which one, and when

- **Pick the RTX 4090:** when 24 GB holds your model. It saves $199/month, and memory you do not use is memory you paid for.
- **Pick the A100 PCIe:** when your model needs more than 24 GB on a single card. That is a threshold, not a preference — below it, the extra $199/month buys you nothing.
- **Neither, if:** your model does not fit on a single card of either. Sharding costs synchronisation at every layer — see the [interconnect guide](https://gpuserver.io/guides/nvlink-vs-pcie) before buying a multi-GPU node.

## Side by side

**RTX 4090 compared with A100 PCIe**

|  | [RTX 4090](https://gpuserver.io/gpu/rtx-4090) | [A100 PCIe](https://gpuserver.io/gpu/a100-40gb) | Difference |
|---|---|---|---|
| Architecture | Ada Lovelace | Ampere | Ada Lovelace is a different generation |
| Memory per card | 24 GB GDDR6X | 40 GB HBM2 | 16 GB in favour of the A100 PCIe |
| Memory bandwidth Predicts generation speed | 1,008 GB/s | 1,555 GB/s | 1.54× in favour of the A100 PCIe |
| Form factor | PCIe add-in card | PCIe add-in card | Same |
| Node sizes | 1×, 2×, 4×, 8× | 1×, 2×, 4×, 8× | Up to 320 GB in one node |
| From, per month | $193 | $392 | $199/month apart |

## Price at every node size

**Monthly price of both cards at each available node size**

| Node | RTX 4090 | A100 PCIe | Total VRAM |  |
|---|---|---|---|---|
| 1 × GPU | $193/mo | $392/mo | 24 GB / 40 GB | [RTX 4090](https://gpuserver.io/configure?c=rtx4090-x1) [A100 PCIe](https://gpuserver.io/configure?c=a100-40-x1) |
| 2 × GPU | $416/mo | $802/mo | 48 GB / 80 GB | [RTX 4090](https://gpuserver.io/configure?c=rtx4090-x2) [A100 PCIe](https://gpuserver.io/configure?c=a100-40-x2) |
| 4 × GPU | $814/mo | $1,556/mo | 96 GB / 160 GB | [RTX 4090](https://gpuserver.io/configure?c=rtx4090-x4) [A100 PCIe](https://gpuserver.io/configure?c=a100-40-x4) |
| 8 × GPU | $1,579/mo | $2,983/mo | 192 GB / 320 GB | [RTX 4090](https://gpuserver.io/configure?c=rtx4090-x8) [A100 PCIe](https://gpuserver.io/configure?c=a100-40-x8) |

## What each one holds on a single card

At 8k context, best precision that fits. This is the difference that decides a purchase — not the specification sheet.

### Only the RTX 4090

Nothing. Every model the RTX 4090 holds on one card, the A100 PCIe holds too — the difference between them is speed, not capability.

### Only the A100 PCIe

Nothing. The RTX 4090 holds everything the A100 PCIe does.

**The same model on both: Qwen 3 32B.** On the RTX 4090, roughly 28 tokens/second at 4-bit (AWQ, GPTQ); on the A100 PCIe, roughly 22. Single-stream and deliberately conservative — with continuous batching the aggregate is several times higher on both. Treat the *ratio* as the useful number, not the absolute.

## Cost per GB and per TB/s

Two ratios that cut through the specification sheet. The first tells you what memory costs; the second what speed costs.

**Cost per gigabyte of VRAM and per terabyte per second of bandwidth**

| Card | $/GB of VRAM, per month | $/TB per second, per month | Better at |
|---|---|---|---|
| [RTX 4090](https://gpuserver.io/gpu/rtx-4090) | $8.04 | $191 | Both ratios |
| [A100 PCIe](https://gpuserver.io/gpu/a100-40gb) | $9.80 | $252 | Neither |

These ratios rank cards; they do not choose one. A card that is cheaper per gigabyte is worthless if it has too few gigabytes to hold your model at all — capacity is a threshold, not a slope. Use them to break a tie between two cards that both fit.

## RTX 4090 against A100 PCIe, in short

Is the RTX 4090 worth the extra money over the A100 PCIe?

It is actually $199 a month cheaper. The A100 PCIe costs more because of its memory or bandwidth; whether that is worth it depends on whether your model fits on the RTX 4090.

Which one is faster for LLM inference?

Generation speed is bounded by memory bandwidth, because each token requires re-reading the active weights. The RTX 4090 has 1,008 GB/s against 1,555 GB/s, so the A100 PCIe leads by roughly 35% on a model both of them hold.

Do both come as multi-GPU nodes?

RTX 4090: 1×, 2×, 4×, 8×. A100 PCIe: 1×, 2×, 4×, 8×. Both are PCIe cards, joined peer-to-peer over the bus rather than by NVLink.

Can I rent either without an identity check?

Yes, both, on the same terms. No document, no selfie, no phone number and no company registration, at any level of spend. Payment is in cryptocurrency, each invoice gets its own address, and root access arrives under 5 minutes after the first confirmation.

## Other comparisons

- [A100 PCIe vs A100 PCIe  The same GPU with twice the memory Compare](https://gpuserver.io/compare/a100-80gb-vs-a100-40gb)
- [RTX 5090 vs RTX 4090  The consumer flagship, one generation apart Compare](https://gpuserver.io/compare/rtx-5090-vs-rtx-4090)
- [RTX 4090 vs L4  Raw speed against low power Compare](https://gpuserver.io/compare/rtx-4090-vs-nvidia-l4)

## Both are racked and waiting, in all 6 data centres.

Whichever you pick, it is monthly, paid in crypto, opened without an identity check and delivered in under 5 minutes.

[Open the configurator](https://gpuserver.io/configure) [Read the guides](https://gpuserver.io/guides)

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