AMD288 GB VRAM6,000 GB/s$3.5/hr

Llama 3.1 405B on AMD MI325X 288GB: Does It Fit, How Fast, What It Costs

Llama 3.1 405B at AWQ 4-bit needs 222.8 GB for its weights and 256.6 GB in total at 8K context with 8 concurrent users. That means it fits on a single AMD MI325X 288GB. Every figure is computed by tokcalc's open-source capacity model.

Fits?
Yes, 1 GPU
256.6 GB needed / 288 GB available
Decode speed
15.41
tok/s per stream
Aggregate
184.9
tok/s @ 8 concurrent
Cost / 1M tokens
$5.26
1× AMD MI325X 288GB
What changes as you add AMD MI325X 288GBs
Tensor-parallel degree vs VRAM, throughput, and cost. Cost scales linearly with GPU count; decode throughput scales near-linearly too, so cost per token stays roughly flat.
GPUsTotal VRAMVRAM neededDecode tok/sAggregate tok/sTTFTCost / 1M tokFits?
1× AMD288 GB256.6 GB15.41184.910.25 s$5.26✓
2× AMD576 GB256.6 GB26.19628.65.15 s$3.09✓
4× AMD1152 GB256.6 GB52.3925142.59 s$1.55✓
8× AMD2304 GB256.6 GB104.8100581.31 s$0.7733✓
Concurrency vs context length
On 1× AMD MI325X 288GB at AWQ 4-bit. KV cache scales linearly with context, so this is the number of users your GPUs can actually serve.
ContextConcurrent usersKV per requestFits?
4K302.11 GB✓ fits
8K154.23 GB✓ fits
33K316.91 GB✓ fits
66K133.82 GB✓ fits
131K067.65 GB✗ does not fit
Other GPUs that run Llama 3.1 405B
Same workload, same quantization — ranked by value (tokens per dollar-hour).
GPUGPUsAggregate tok/sCost / 1M tok
L40S 48GB8×1448$1.07
A100 80GB SXM44×838.2$1.59
H100 SXM5 80GB4×1404$1.98
B200 SXM 192GB2×838.2$3.98
H200 SXM5 141GB2×502.9$4.42
B300 SXM 288GB1×246.5$9.01
Frequently asked questions

Can Llama 3.1 405B run on AMD MI325X 288GB?

Yes. Llama 3.1 405B at AWQ 4-bit needs 256.6 GB including the KV cache, and AMD MI325X 288GB has 288 GB — so it fits on a single GPU.

How fast is Llama 3.1 405B on AMD MI325X 288GB?

15.41 tokens/sec per stream and 184.9 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 10.25 s, and inter-token latency is 64.9 ms.

What does Llama 3.1 405B on AMD MI325X 288GB cost per million tokens?

$5.26 per 1M output tokens at 1× AMD MI325X 288GB ($3.50/hr). That is the marginal hardware cost — add idle capacity, ops, and egress for the real figure.

How much VRAM does Llama 3.1 405B need on AMD MI325X 288GB?

222.8 GB for the weights at AWQ 4-bit, plus 33.8 GB of KV cache for 8 concurrent requests at 8K context — 256.6 GB total. Every extra concurrent user at long context costs more, so leave headroom.

Is AMD MI325X 288GB the right choice for Llama 3.1 405B?

It works. Compare $5.26 per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 8× A100 40GB SXM4 at $0.7697, and the fastest is 8× Cerebras CS-3 (WSE-3) at 33527 tok/s.

Adjust the workload yourself

Same formulas, your context length, concurrency, and quantisation.

Open in calculator