Granite 4.2 8B VRAM requirements
Granite 4.2 8B has 8.8B parameters. With an 8K-token context and one request it needs about 7.32 GB of GPU memory at Q4_K_M, 10.9 GB at FP8 and 19.9 GB at FP16/BF16. The published weights take 16.4 GB (BF16). The smallest setup here that holds it at Q4_K_M with an 8K context is the RTX 4060 8GB; on one 24 GB RTX 3090 / 4090 it runs with up to 101K tokens of context.
7.32 GB at Q4_K_M, 8K context, one request
- FP8
- 10.9 GB
- FP16 / BF16
- 19.9 GB
- Published weights
- 16.4 GB
- Smallest setup, Q4_K_M
- RTX 4060 8GB
Worked example: Granite 4.2 8B with 32K tokens
Inputs: Granite 4.2 8B · Q4_K_M weights · 32,768 tokens of context · one request · FP16 KV cache
- Weights (8.8B at Q4_K_M)
- 4.95 GB
- KV cache (160 KB per token)
- 5.00 GB
- Buffers and runtime (0.5 GB + 10%)
- 1.50 GB
- Total
- 11.4 GB
The smallest setup here that holds it is the RTX 3060 12GB, with about 564 MB to spare. Change the inputs in the calculator
What makes Granite 4.2 8B's memory use different
Per token of context it adds 160 KB of FP16 cache; Qwen3 8B (8.2B), the nearest-sized model here with plain full attention, adds 144 KB, so Granite 4.2 8B needs 11% more.
How much VRAM does Granite 4.2 8B need?
Granite 4.2 8B needs 7.32 GB at Q4_K_M, 11.4 GB at Q8_0 and 19.9 GB at FP16 with 8,192 tokens of context and one request. Each total below is the weights plus the FP16 KV cache and the runtime overhead (0.5 GB plus 10%), and each row opens the calculator with that setting. What the GGUF names mean.
| Precision | Weights | Total | Smallest setup |
|---|---|---|---|
| As published (BF16) | 16.4 GB | 19.9 GB | RTX 3090 (24 GB) |
| FP16 / BF16 | 16.4 GB | 19.9 GB | RTX 3090 (24 GB) |
| FP8 / INT8 | 8.19 GB | 10.9 GB | RTX 3060 12GB |
| INT4 (AWQ / GPTQ) | 4.35 GB | 6.66 GB | RTX 4060 8GB |
| GGUF Q8_0 | 8.70 GB | 11.4 GB | RTX 3060 12GB |
| GGUF Q6_K | 6.71 GB | 9.26 GB | RTX 3060 12GB |
| GGUF Q5_K_M | 5.80 GB | 8.26 GB | RTX 3060 12GB |
| GGUF Q4_K_M | 4.95 GB | 7.32 GB | RTX 4060 8GB |
| GGUF IQ4_XS | 4.45 GB | 6.77 GB | RTX 4060 8GB |
| GGUF Q3_K_M | 4.00 GB | 6.28 GB | RTX 4060 8GB |
| GGUF IQ3_XXS | 3.38 GB | 5.59 GB | RTX 4060 8GB |
| GGUF Q2_K | 3.43 GB | 5.65 GB | RTX 4060 8GB |
Fine-tuning Granite 4.2 8B? Granite 4.2 8B VRAM for LoRA, QLoRA and full training.
Granite 4.2 8B GGUF files on Hugging Face
The 8 GGUF files llama.cpp picks for Granite 4.2 8B with -hf <repo>:<QUANT>, with the bytes the Hugging Face file list reported on 2026-09-29. Each total is that file plus the FP16 KV cache and 0.5 GB + 10%, one request. "vs estimate" compares the file with the bits-per-weight size the table above uses.
| Quant | File | Size | vs estimate | 8K | 32K | 128K |
|---|---|---|---|---|---|---|
| Q2_K | bartowski/ | 3.33 GB3,577,463,200 bytes | −3% | 5.54 GB | 9.66 GB | 26.2 GB |
| Q3_K_M | bartowski/ | 4.18 GB4,487,561,632 bytes | +4% | 6.47 GB | 10.6 GB | 27.1 GB |
| IQ4_XS | bartowski/ | 4.60 GB4,939,563,424 bytes | +3% | 6.94 GB | 11.1 GB | 27.6 GB |
| Q4_K_M | bartowski/ | 5.16 GB5,539,283,360 bytes | +4% | 7.55 GB | 11.7 GB | 28.2 GB |
| Q5_K_M | bartowski/ | 5.97 GB6,409,863,584 bytes | +3% | 8.44 GB | 12.6 GB | 29.1 GB |
| Q6_K | bartowski/ | 7.00 GB7,521,223,072 bytes | +4% | 9.58 GB | 13.7 GB | 30.2 GB |
| Q8_0 | bartowski/ | 8.70 GB9,345,614,240 bytes | ±0% | 11.4 GB | 15.6 GB | 32.1 GB |
| BF16 | bartowski/ | 16.4 GB17,587,421,312 bytes | ±0% | 19.9 GB | 24.0 GB | 40.5 GB |
GB here is GiB (1024³ bytes), as everywhere on this site; Hugging Face shows the Q4_K_M file as 5.5 GB, in 10⁹ bytes.
Which Granite 4.2 8B GGUF fits a 16, 24, 32, 48 or 80 GB GPU or a Mac
From the file sizes above: the largest file that fits each machine with an 8K context and 0.5 GB left free, the longest context it then has room for, and the longest context for Q4_K_M (5.16 GB). One request, FP16 KV cache.
| Hardware | Largest GGUF, 8K | Its longest context | Q4_K_M, longest context |
|---|---|---|---|
| RTX 5060 Ti 16GB | Q8_0, 8.70 GB | 31K | 54K |
| RTX 4090 (24 GB) | BF16, 16.4 GB | 28K | 100K |
| RTX 5090 (32 GB) | BF16, 16.4 GB | 75K | 128K (full) |
| L40S (48 GB) | BF16, 16.4 GB | 128K (full) | 128K (full) |
| H100 SXM (80 GB) | BF16, 16.4 GB | 128K (full) | 128K (full) |
| M4 Pro Mac (64 GB, 48 GB usable) | BF16, 16.4 GB | 128K (full) | 128K (full) |
| M4 Max Mac (128 GB, 96 GB usable) | BF16, 16.4 GB | 128K (full) | 128K (full) |
Run Granite 4.2 8B with llama.cpp or Ollama
llama-server -hf bartowski/granite-4.2-8b-GGUF:Q4_K_M -c 102400 granite-4.2-8b-Q4_K_M.gguf, 5.5 GB, from bartowski/
ollama run granite4.2:8b
Ollama library tag granite4.2:8b; its quant is Ollama's choice. Same context: /set parameter num_ctx 102400.
Granite 4.2 8B at 8K, 32K and 128K (full) tokens of context
All 40 layers use full attention. Each extra token of context adds 160 KB of FP16 cache per request. The last column is the smallest setup here, one card or a group, that holds it at Q4_K_M. How the KV cache works.
| Context | KV cache, FP16 | Total at Q4_K_M | Total at Q8_0 | Smallest setup, Q4_K_M |
|---|---|---|---|---|
| 8K tokens | 1.25 GB | 7.32 GB | 11.4 GB | RTX 4060 8GB |
| 32K tokens | 5.00 GB | 11.4 GB | 15.6 GB | RTX 3060 12GB |
| 128K tokens | 20.0 GB | 27.9 GB | 32.1 GB | RTX 5090 (32 GB) |
How fast Granite 4.2 8B writes
Tokens per second for one request with 8,192 tokens of context, estimated from memory bandwidth. A dash means it does not fit on one card. Try other settings in the speed calculator.
| Hardware | Bandwidth | Q4_K_M | FP8 |
|---|---|---|---|
| RTX 3060 12GB | 360 GB/s | 28–40 | 19–26 |
| RTX 4090 | 1,008 GB/s | 74–107 | 51–72 |
| RTX 5090 | 1,792 GB/s | 121–183 | 85–124 |
| M4 Max Mac (128 GB) | 546 GB/s | 42–60 | 28–40 |
| M3 Ultra Mac Studio (512 GB) | 819 GB/s | 61–88 | 42–59 |
| H100 SXM | 3,350 GB/s | 195–317 | 143–221 |
| H200 | 4,800 GB/s | 249–425 | 187–302 |
Longest context on one GPU
How many tokens of context Granite 4.2 8B fits on a single card with one request, an FP16 KV cache and 0.5 GB left free. "Full" means the model's whole context window fits.
| GPU | Memory | Q4_K_M | Q8_0 | FP8 |
|---|---|---|---|---|
| RTX 3060 | 12 GB | 32K | 8K | 11K |
| RTX 4060 Ti 16GB | 16 GB | 55K | 31K | 34K |
| RTX 3090 / 4090 | 24 GB | 101K | 77K | 81K |
| RTX 5090 | 32 GB | 128K (full) | 124K | 127K |
| A100 40GB | 40 GB | 128K (full) | 128K (full) | 128K (full) |
| Mac, 64 GB unified memory | 48 GB | 128K (full) | 128K (full) | 128K (full) |
| L40S / RTX 6000 Ada | 48 GB | 128K (full) | 128K (full) | 128K (full) |
| A100 / H100 80GB | 80 GB | 128K (full) | 128K (full) | 128K (full) |
| Mac, 128 GB unified memory | 96 GB | 128K (full) | 128K (full) | 128K (full) |
| H200 | 141 GB | 128K (full) | 128K (full) | 128K (full) |
| B200 | 180 GB | 128K (full) | 128K (full) | 128K (full) |
Model details
- Parameters
- 8.8B (8,791,592,960)
- Layers
- All 40 layers use full attention
- Attention cache
- 8 KV heads × 128
- Context length
- 131,072 tokens
- Published weights
- 16.4 GB (BF16)
- On Hugging Face
- ibm-granite/
granite-4.2-8b
Why this estimate looks this way
At Q4_K_M and an 8K-token context, Granite 4.2 8B uses 4.95 GB for weights, 1.25 GB for its FP16 KV cache and 1.12 GB for estimated runtime overhead, totaling 7.32 GB. The overhead is a 0.5 GB base plus 10% of weights and cache.
The architecture and published checkpoint size come from the model's config.json and weight files. These are estimates rather than measured peak memory; inference engines can reserve extra buffers or preallocate the full configured cache.
Granite 4.2 8B next to similar-sized models
The three models here closest to it in parameter count, at Q4_K_M with 8,192 tokens of context.
| Model | Parameters | Total | KV per token | Smallest setup |
|---|---|---|---|---|
| Granite 4.2 8B | 8.8B | 7.32 GB | 160 KB | RTX 4060 8GB |
| LFM2.5 8B-A1B | 8.5B, 1.5B active | 5.85 GB | 12 KB | RTX 4060 8GB |
| Ornith 1.0 9B | 9.4B | 6.61 GB | 32 KB | RTX 4060 8GB |
| MiMo V2.6 Distill Qwen 9B | 9.4B | 6.61 GB | 32 KB | RTX 4060 8GB |
Granite 4.2 8B VRAM questions
How much VRAM do I need to run Granite 4.2 8B locally?
About 7.32 GB at Q4_K_M with an 8K context and one request, by the bits-per-weight estimate, and 19.9 GB at BF16. The Q4_K_M GGUF granite-4.2-8b-Q4_K_M.gguf in bartowski/
Can I run Granite 4.2 8B on a 24 GB GPU?
Yes. On the RTX 4090 (24 GB), the largest listed GGUF that fits with an 8K context and 0.5 GB free is BF16 (16.4 GB), with up to 28K tokens of context. Q4_K_M (5.16 GB) runs with up to 100K tokens of context.
Which quantization of Granite 4.2 8B fits in 16 GB of VRAM?
On the RTX 5060 Ti 16GB, the largest listed GGUF that fits with an 8K context and 0.5 GB free is Q8_0 (8.70 GB), with up to 31K tokens of context. Q4_K_M (5.16 GB) runs with up to 54K tokens of context.
Can I run Granite 4.2 8B on a Mac?
On the M4 Pro Mac (64 GB, 48 GB usable), the largest listed GGUF that fits with an 8K context and 0.5 GB free is BF16 (16.4 GB), with its full 128K-token context. On the M4 Max Mac (128 GB, 96 GB usable), the largest listed GGUF that fits with an 8K context and 0.5 GB free is BF16 (16.4 GB), with its full 128K-token context. By default macOS lets the GPU use about 75% of unified memory.
How much more VRAM does Granite 4.2 8B need for 32K or 128K tokens of context?
Its FP16 KV cache is 1.25 GB at 8K, 5.00 GB at 32K, 20.0 GB at 128K for one request, so 128K adds 18.8 GB over 8K, plus 10% overhead. A q8_0 cache
Why does Granite 4.2 8B use more VRAM than its GGUF file size?
The file holds only the weights. At Q4_K_M with an 8K context: 5.16 GB of weights (the file's 5,539,283,360 bytes) + 1.25 GB of FP16 KV cache + 1.14 GB of compute buffers and runtime (0.5 GB + 10%) = 7.55 GB.
Badge for your model card
Paste it into a Hugging Face or GitHub README; it shows the Q4_K_M total above and links to this page. Q8_0 and FP16 badges.
Numbers read from the model files on Hugging Face on . Compare it with other models in the reproducible model and GPU report.