Carbon X — Hardware Requirements & GPU Compatibility
ChatFunctions
Carbon X is a 14.8B-parameter open language model from HuggingFaceBio. It supports a context window of up to 40,960 tokens. At Q4_K_M it needs about 9.53 GB of VRAM — see which GPUs and Macs can run it below.
Runs great on a 24 GB GPU
Runs from 12 GB (Q4_K_M · 16K)Best on 24 GB (Q4_K_M · ~69 tok/s · 40K)Macs from 16 GB (Q4_K_M · ~15 tok/s)
Apache 2.0
Reference GPU · RTX 4090 24 GB
Estimates, ±20% · how we estimate
Run Carbon X
One recommended way. Every other method, OS and quant is in the step-by-step guide.Each way opens a step-by-step guide for your OS and quant.
Recommended
vllm serve HuggingFaceBio/Carbon-X --max-model-len 16384vLLM repo with its own quantisation
Download: Weights on Hugging Face
Ways to runOther ways
each opens step-by-stepRun in cloud
Runs on RTX 3090 (24 GB) (12 GB headroom) · Q4_K_M
- Generation speed
- ~64 tok/s
- generation speed
- Cost per 1M output tokens
- $0.79
- per 1M output tokens
How Much VRAM Does Carbon X Need?
Select a quantization level; the listed hardware adheres to it.
| Quantization | VRAM | +32K | On RTX 4090 (reference) | |
|---|---|---|---|---|
| 6.9 GB | 12 GB | 2-bit · K-quant — 2-bit quantization with K-quant improvements | Fits: 40K context · ~95 tok/s | |
| 7.9 GB | 12.9 GB | 3-bit medium — 3-bit medium quantization | Fits: 40K context · ~83 tok/s | |
| 9.5 GB | 14.6 GB | 4-bit medium — 4-bit medium quantization — most popular sweet spot | Fits: 40K context · ~69 tok/s | |
| 11.2 GB | 16.2 GB | 5-bit medium — 5-bit medium quantization — good quality/size tradeoff | Fits: 40K context · ~59 tok/s | |
| 12.9 GB | 17.9 GB | 6-bit, very good — 6-bit quantization, very good quality | Fits: 40K context · ~51 tok/s | |
| 15.5 GB | 20.5 GB | 8-bit, near-lossless — 8-bit quantization, near-lossless | Fits: 40K context · ~42 tok/s | |
| 30.3 GB | 35.3 GB | 16-bit · bfloat — Brain floating point 16 — preferred for training | Does not fit: needs 32.6 GB |
Selected Q4_K_M
4-bit medium quantization11.9GBat 16K context
- Weights
- 8.9 GB
- KV cache
- 2.7 GB
- Overhead
- 0.3 GB
Fits RTX 4090 (reference) · 12.1 GB free · ~69 tok/s
≥50 tok/s needs ≥732 GB/s · RTX 5090 ~122, RTX 3090 Ti ~69
Which Hardware Can Run Carbon X?
Q4_K_M · 9.5 GBCarbon X (Q4_K_M) requires 9.5 GB of VRAM to load the model weights. For comfortable inference with headroom for KV cache and system overhead, 13+ GB is recommended. Using the full 41K context window can add up to 6.4 GB, bringing total usage to 15.9 GB. 40 GPUs can run it, including NVIDIA GeForce RTX 5090, NVIDIA GeForce RTX 3090 Ti, NVIDIA GeForce RTX 3080 Ti. 150 devices with unified memory can run Carbon X, including Mac Studio (M3 Ultra, 256GB), Mac Studio (M3 Ultra, 512GB), Mac Mini M2 Pro (16 GB).
12 GB
12 GB tier →fits · 0.1 GB free · up to 16K ctx
10 GPUs
RTX 3080 Ti~62Simulate output on RTX 3080 TiRTX 5070~46Simulate output on RTX 5070RTX 4070~34Simulate output on RTX 407020 GB
fits · 8.1 GB free · up to 40K ctx
1 GPU
RX 7900 XT~50Simulate output on RX 7900 XT32–40 GB
fits · 20.1 GB free · up to 40K ctx
1 GPU · 3 Mac classes · 4 device families
RTX 5090~122Simulate output on RTX 5090M5 Max36 GB~34Simulate output on Mac Studio M5 Max (36 GB)M532 GB~11Simulate output on MacBook Air 13" M5 (32 GB)Orin~14Simulate output on NVIDIA Jetson AGX Orin 32GBSnapdragon X Elite (X1E-80-100)~9Simulate output on Snapdragon X Elite Copilot+ PC
By VRAM tier · typical GPUs and Macs at Q4_K_M
Similar models
6| Model | Score | VRAM | tok/s | Why it is similar |
|---|---|---|---|---|
| Phi 4 ReasoningMicrosoft | — | 12.5 GB | ~69 | same size |
| Phi 3 Medium 128k InstructMicrosoft | — | 12 GB | ~72 | same size |
| Qwen1.5 14BAlibaba | — | 22.2 GB | ~63 | same size |
| Nemotron Terminal 14BNVIDIA | — | 11.9 GB | ~69 | same size |
| Ministral 3 14B Reasoning 2512Mistral AI | — | 12 GB | ~72 | same size |
| Qwen3 14B BaseAlibaba | — | 11.9 GB | ~69 | same size |
Specifications
- Publisher
- HuggingFaceBio
- Parameters
- 14.8B
- Architecture
- Qwen3ForCausalLM
- Context Length
- 40,960 tokens
- Vocabulary Size
- 157,184
- Release Date
- 2026-10-21
- License
- Apache 2.0
Frequently Asked Questions
How much VRAM does Carbon X need?
Carbon X requires 9.5 GB of VRAM at Q4_K_M, or 30.3 GB at BF16. Full 41K context adds up to 6.4 GB (15.9 GB total).
VRAM = Weights + KV Cache + Overhead
Weights = 14.8B × 4.8 bits ÷ 8 = 8.9 GB
KV Cache + Overhead ≈ 0.6 GB (at 2K context + ~0.3 GB framework)
Fit ratings and hardware model lists check this model with room for a 16K-token context, which needs a little more memory.
KV Cache + Overhead ≈ 7 GB (at full 41K context)
VRAM usage by quantization
Can NVIDIA GeForce RTX 4090 run Carbon X?
Yes, at Q8_0 (15.5 GB) or lower. Higher quantizations like BF16 (30.3 GB) exceed the NVIDIA GeForce RTX 4090's 24 GB.
What's the best quantization for Carbon X?
For Carbon X, Q4_K_M (9.5 GB) offers the best balance of quality and VRAM usage. Q5_K_M (11.2 GB) provides better quality if you have the VRAM. The smallest option is Q2_K at 6.9 GB.
VRAM requirement by quantization
★ Recommended — best balance of quality and VRAM usage.
Can I run Carbon X on a Mac?
Yes — Mac Mini M2 Pro (16 GB) and 133 other Macs can run Carbon X. Apple Silicon uses unified memory, so the model shares RAM with the system. At Q4_K_M you need at least 9.5 GB of usable unified memory (RAM minus macOS overhead).
Can I run Carbon X locally?
Yes — Carbon X can run locally on consumer hardware. Popular tools include Ollama, LM Studio, and llama.cpp.
How fast is Carbon X?
At Q4_K_M, Carbon X can reach ~504 tok/s on AMD Instinct MI350X. On NVIDIA GeForce RTX 4090: ~69 tok/s. Speed depends mainly on GPU memory bandwidth. Real-world results typically within ±20%.
tok/s = (bandwidth GB/s ÷ model GB) × efficiency
Example: NVIDIA B200 → 8000 ÷ 9.53 × 0.65 = ~546 tok/s
Estimated speed at Q4_K_M (9.5 GB)
Real-world results typically within ±20%. Speed depends on batch size, quantization kernel, and software stack.
What's the download size of Carbon X?
At Q4_K_M, the download is about 8.89 GB. The full-precision BF16 version is 29.64 GB. The smallest option (Q2_K) is 6.30 GB.
Which GPUs can run Carbon X?
40 consumer GPUs can run Carbon X at Q4_K_M. Top options include AMD Radeon RX 6800, AMD Radeon RX 6800 XT, AMD Radeon RX 6900 XT, AMD Radeon RX 6700 XT. 26 GPUs have plenty of headroom for comfortable inference.
Which devices can run Carbon X?
150 devices with unified memory can run Carbon X at Q4_K_M (9.5 GB), including AMD Ryzen AI 9 HX 370 (Strix Point) Laptop, ASUS Ascent GX10, Beelink GTR9 Pro (Ryzen AI Max+ 395, 128 GB), Framework Desktop (Ryzen AI Max+ 395, 128 GB). Apple Silicon Macs use unified memory shared between CPU and GPU, making them well-suited for local LLM inference.