Laguna S 2.1 on an A100 40GB (SXM)
No. Even Q3_K_M needs 50.3 GiB against 36.8 GiB usable.
Verdict
Does not fit
36.8 GiB usable of 40 GB
Weights (Q4_K_M)
66.8 GiB
219.0 GiB at FP16 · 117.6B params · 6 of 6 quant rows are measured files
KV cache
192.0 KiB per token at FP16
48 layers × 8 KV heads × 128 dimensions
Speed ceiling
59.5 tok/s
offloaded — nothing fits in device memory
Every quant, against this card
Weight bytes are the size of the real published file wherever one exists — 6 of these6 rows are measured from bartowski/Laguna-S-2.1-GGUF, the rest computed from the parameter count. Max context is what the KV cache can grow to in whatever memory the weights leave behind, capped at the 1.0M tokens this model was trained to address.
| Precision | Bits/weight | Weights | Source | Fits | Max context | Ceiling |
|---|---|---|---|---|---|---|
| FP16 / BF16 | 16.00 | 219.0 GiB | measured file | −182.2 GiB | — | 7.1 tok/s offloaded |
| Q8_0 | 8.51 | 116.4 GiB | measured file | −79.6 GiB | — | 15.3 tok/s offloaded |
| Q6_K | 6.92 | 94.7 GiB | measured file | −57.9 GiB | — | 20.3 tok/s offloaded |
| Q5_K_M | 5.72 | 78.2 GiB | measured file | −41.4 GiB | — | 26.8 tok/s offloaded |
| Q4_K_M | 4.88 | 66.8 GiB | measured file | −30.0 GiB | — | 34.6 tok/s offloaded |
| Q3_K_M | 3.68 | 50.3 GiB | measured file | −13.5 GiB | — | 59.5 tok/s offloaded |
What the context actually costs
The KV cache is 2 · layers · kv_heads · head_dim bytes per token per element — 2 · 48 · 8 · 128 · 2 B = 192.0 KiB. It depends on the key/value head count, not the attention-head count and not the parameter count. This model shares 8 KV heads across 48 query heads, which divides the cache by 6 against multi-head attention.
Sliding-window attention. 36 of this model's 48 layers attend to a 512-token window and stop growing there; only the remaining 12 keep scaling with context. That is why the cache figures below flatten out — and why a calculator that ignores the layer pattern over-states this model's long-context footprint several times over.
| Context | KV cache (FP16) | KV cache (8-bit) | Plus Q4_K_M weights |
|---|---|---|---|
| 4,096 | 264 MiB | 132 MiB | 67.1 GiB |
| 8,192 | 456 MiB | 228 MiB | 67.3 GiB |
| 32,768 | 1.6 GiB | 804 MiB | 68.4 GiB |
| 131,072 | 6.1 GiB | 3.0 GiB | 72.9 GiB |
What running it anyway would cost
Nothing here fits, so the weights would have to be split with part of the model in host RAM. At Q3_K_M that is 13.5 GiB on the host side, and assuming 90 GB/s of host memory bandwidth — a dual-channel DDR5 desktop — the ceiling falls to 59.5 tok/s, against 409.2 tok/s if the same weights were resident — 1555 GB/s over the 3.80 GB one token reads, which is the weights the model routes through plus one pass over the cache, against a 54.04 GB weight file. That host bandwidth is an assumption and it is the number to change first if your machine differs; the ratio is the part that generalises.
Where these numbers come from
The model
- Parameters
- 117,561,977,600
- Layers
- 48
- Attention / KV heads
- 48 / 8
- Head dimension
- 128
- Trained context
- 1,048,576
- Checkpoint as published
- 219.0 GiB
Read from poolside/Laguna-S-2.1. The parameter count is the Hub's own total over the tensor shapes, not a figure taken from the model's name.
The accelerator
- Memory
- 40 GB HBM2
- Bandwidth
- 1555 GB/s
- Assumed usable
- 92% → 36.8 GiB
Capacity and bandwidth from the vendor's specification. The usable fraction is an assumption, not a spec: a driver context, compute workspace and any attached display come out of the same pool before a weight is loaded.
Questions this pairing answers
How much VRAM does Laguna S 2.1 need?
219.0 GiB for the weights at FP16 — 117.6B parameters at two bytes each — and 66.8 GiB at Q4_K_M. The KV cache is on top of that and is not a fixed number: this model spends 192.0 KiB per token of context on its full-attention layers, so 8,192 tokens costs a further 456 MiB. An A100 40GB (SXM) makes 36.8 GiB of its 40 GB available on the assumption below.
Can an A100 40GB (SXM) run Laguna S 2.1?
No. Even Q3_K_M needs 50.3 GiB against 36.8 GiB usable. Holding the smallest quant here would need a card with about 55 GB. Splitting the model across the PCIe bus is possible and slow — see the offload figure on this page.
How fast will Laguna S 2.1 run on an A100 40GB (SXM)?
It cannot run in this card's memory alone, so the speed is set by whatever bus the offloaded part is read across, not by the 1555 GB/s of the card. At an assumed 90 GB/s of host memory bandwidth the ceiling is 59.5 tok/s at Q3_K_M, against 409.2 tok/s if it were resident — 1555 GB/s over the 3.80 GB one token reads at Q3_K_M, priced at the 8k reference context. That is the weights the model routes through plus one pass over the cache, against a 54.04 GB weight file.
Why does the context length change how much memory Laguna S 2.1 needs?
Because the KV cache holds one key and one value vector per token, per layer, for the whole conversation, and it is allocated separately from the weights. This model has 48 layers and 8 key/value heads of 128 dimensions, shared across 48 query heads — grouped-query attention, which divides the cache by 6. That works out at 192.0 KiB per token, except that 36 of the 48 layers use a 512-token sliding window and stop growing there. Parameter count tells you nothing about this number.
The same model on a different card
- GeForce RTX 5090no fit
- RTX 6000 Ada Generationno fit
- L40Sno fit
- Apple M4 Pro (48GB)no fit
- GeForce RTX 4090no fit
- GeForce RTX 3090no fit
- Radeon RX 7900 XTXno fit
- Apple M4 (24GB)no fit
A different model on the same card
All 62 models on A100 40GB (SXM) →- gpt-oss 120Bno fit
- Qwen2.5 72B InstructQ3_K_M
- DeepSeek-R1-Distill-Llama 70BQ3_K_M
- Llama 3.1 70B InstructQ3_K_M
- Llama 3.1 Nemotron 70B InstructQ3_K_M
- Llama 3.3 70B InstructQ3_K_M
- Mixtral 8x7B InstructQ6_K
- Hermes 4.3 36BQ8_0
Method and limits. Weight bytes are the byte size of the real published file wherever one exists, and the model's exact parameter count times the published llama.cpp bits-per-weight where it does not. That distinction is on every row above and it matters at both ends: a sub-1B model's Q4_K_M file runs a third larger than the nominal figure because k-quants keep its embedding tables at higher precision, and an already-4-bit release cannot be quantized upward at all. The KV cache is 2 · layers · kv_heads · head_dim · bytes per token, summed over layers with each sliding-window layer capped at its window. The speed figure is a roofline bound, not a benchmark: bandwidth divided by bytes read per token, which no runtime exceeds and every runtime falls short of. The usable fraction of card memory is an assumption: 92% here, which is what this lane assumes for a dedicated card — the other class assumes 75%, so it is not one number applied to every device. Because nothing here fits, a second assumed input is in play — the 90 GB/s of host memory bandwidth the offload ceiling is priced at, stated above. Those two are the assumed inputs; every other figure is computed from the model config and the card's published specification. Nothing on this page is written by a language model. Architecture from the model's published config, fetched 2026-08-07.