JiRackUltra 1B — Hardware Requirements & GPU Compatibility
ChatFunctions
JiRackUltra 1B is a 1.8B-parameter open language model from CMSManhattan. It supports a context window of up to 131,072 tokens. At Q4_K_M it needs about 1.42 GB of VRAM — see which GPUs and Macs can run it below.
Runs great on a 24 GB GPU
Runs from 8 GB (Q4_K_M · 128K)Best on 24 GB (Q4_K_M · ~461 tok/s · 128K)Macs from 8 GB (Q4_K_M · ~51 tok/s)
MIT
Reference GPU · RTX 4090 24 GB
Estimates, ±20% · how we estimate
Run JiRackUltra 1B
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
ollama run hf.co/mradermacher/JiRackUltra_1b-i1-GGUF:Q4_K_MQ4_K_M fits fully on the RTX 4090 · 22.2 GB free · 16K context
Download: JiRackUltra_1b.i1-Q4_K_M.gguf1.12 GBmradermacher
Ways to runOther ways
each opens step-by-stepRun in cloud
Your own private copy · Q4_K_M · 24 GB GPU
- The easiest way to try this model
- Running in a few minutes, easy setup
- Chat right here or connect any app
$5+ bonus for new users
Runs on RTX 3080 Ti (12 GB) (10 GB headroom) · Q4_K_M
- Generation speed
- ~418 tok/s
- generation speed
- Cost per 1M output tokens
- $0.081
- per 1M output tokens
How Much VRAM Does JiRackUltra 1B Need?
Select a quantization level; the listed hardware adheres to it.
| Quantization | VRAM | +32K | On RTX 4090 (reference) | |
|---|---|---|---|---|
| 1.1 GB | 2 GB | 2-bit · K-quant — 2-bit quantization with K-quant improvements | Fits: 128K context · ~590 tok/s | |
| 1.1 GB | 2 GB | 3-bit small — 3-bit small quantization | Fits: 128K context · ~575 tok/s | |
| 1.2 GB | 2.1 GB | 3-bit medium — 3-bit medium quantization | Fits: 128K context · ~533 tok/s | |
| 1.3 GB | 2.1 GB | 4-bit · legacy — 4-bit legacy quantization | Fits: 128K context · ~524 tok/s | |
| 1.4 GB | 2.3 GB | 4-bit medium — 4-bit medium quantization — most popular sweet spot | Fits: 128K context · ~461 tok/s | |
| 1.6 GB | 2.5 GB | 5-bit medium — 5-bit medium quantization — good quality/size tradeoff | Fits: 128K context · ~404 tok/s | |
| 1.8 GB | 2.7 GB | 6-bit, very good — 6-bit quantization, very good quality | Fits: 128K context · ~360 tok/s | |
| 2.1 GB | 3 GB | 8-bit, near-lossless — 8-bit quantization, near-lossless | Fits: 128K context · ~306 tok/s |
Selected Q4_K_M
4-bit medium quantization1.8GBat 16K context
- Weights
- 1.1 GB
- KV cache
- 0.5 GB
- Overhead
- 0.3 GB
Fits RTX 4090 (reference) · 22.2 GB free · ~461 tok/s
≥50 tok/s needs ≥109 GB/s · RTX 5090 ~820, RTX 3090 Ti ~461
Which Hardware Can Run JiRackUltra 1B?
Q4_K_M · 1.4 GBJiRackUltra 1B (Q4_K_M) requires 1.4 GB of VRAM to load the model weights. For comfortable inference with headroom for KV cache and system overhead, 2+ GB is recommended. Using the full 131K context window can add up to 3.7 GB, bringing total usage to 5.1 GB. 52 GPUs can run it, including NVIDIA GeForce RTX 5090, NVIDIA GeForce RTX 3090 Ti. 163 devices with unified memory can run JiRackUltra 1B, including Mac Studio (M3 Ultra, 256GB), Mac Studio (M3 Ultra, 512GB).
≤ 11 GB
≤ 11 GB tier →fits · 6.2 GB free · up to 128K ctx
16 GPUs · 1 Mac class · 2 device families
RTX 3080~348Simulate output on RTX 3080RTX 2080 Ti~282Simulate output on RTX 2080 TiRTX 3070 Ti~278Simulate output on RTX 3070 TiM3*8 GB~51Simulate output on iMac 24" M3 (8 GB)Orin Nano~47Simulate output on NVIDIA Jetson Orin Nano 8GB (Super)iPhone~34Simulate output on iPhone 1720 GB
fits · 18.2 GB free · up to 128K ctx
1 GPU
RX 7900 XT~338Simulate output on RX 7900 XT32–40 GB
fits · 30.2 GB free · up to 128K ctx
1 GPU · 3 Mac classes · 4 device families
RTX 5090~820Simulate output on RTX 5090M5 Max36 GB~227Simulate output on Mac Studio M5 Max (36 GB)M532 GB~76Simulate output on MacBook Air 13" M5 (32 GB)Orin~94Simulate output on NVIDIA Jetson AGX Orin 32GBSnapdragon X Elite (X1E-80-100)~62Simulate output on Snapdragon X Elite Copilot+ PC
By VRAM tier · typical GPUs and Macs at Q4_K_M
Similar models
5| Model | Score | VRAM | tok/s | Why it is similar |
|---|---|---|---|---|
| LFM3 1.7BLiquid AI | — | 2.1 GB | ~455 | same size |
| Qwen 1 8BAlibaba | — | 1.9 GB | ~542 | same size |
| Qwen3 1.7B BaseAlibaba | — | 3.2 GB | ~417 | same size |
| DeepSeek R1 Distill Qwen 1.5BDeepSeek | — | 1.8 GB | ~461 | same size |
| SmolLM2 1.7B InstructHugging Face | — | 2.9 GB | ~379 | same size |
Specifications
- Publisher
- CMSManhattan
- Parameters
- 1.8B
- Architecture
- Qwen2ForCausalLM
- Context Length
- 131,072 tokens
- Vocabulary Size
- 151,936
- Release Date
- 2026-08-02
- License
- MIT
Frequently Asked Questions
How much VRAM does JiRackUltra 1B need?
JiRackUltra 1B requires 1.4 GB of VRAM at Q4_K_M, or 3.9 GB at BF16. Full 131K context adds up to 3.7 GB (5.1 GB total).
VRAM = Weights + KV Cache + Overhead
Weights = 1.8B × 4.8 bits ÷ 8 = 1.1 GB
KV Cache + Overhead ≈ 0.3 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 ≈ 4 GB (at full 131K context)
VRAM usage by quantization
What's the best quantization for JiRackUltra 1B?
For JiRackUltra 1B, Q4_K_M (1.4 GB) offers the best balance of quality and VRAM usage. Q5_K_S (1.6 GB) provides better quality if you have the VRAM. The smallest option is IQ2_XXS at 0.8 GB.
VRAM requirement by quantization
★ Recommended — best balance of quality and VRAM usage.
Can I run JiRackUltra 1B on a Mac?
Yes — MacBook Air 13" M3 (8 GB) and 145 other Macs can run JiRackUltra 1B. Apple Silicon uses unified memory, so the model shares RAM with the system. At Q4_K_M you need at least 1.4 GB of usable unified memory (RAM minus macOS overhead).
Can I run JiRackUltra 1B locally?
Yes — JiRackUltra 1B can run locally on consumer hardware. Popular tools include Ollama, LM Studio, and llama.cpp.
How fast is JiRackUltra 1B?
At Q4_K_M, JiRackUltra 1B can reach ~3380 tok/s on AMD Instinct MI350X. On NVIDIA GeForce RTX 4090: ~461 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 ÷ 1.42 × 0.65 = ~3662 tok/s
Estimated speed at Q4_K_M (1.4 GB)
Real-world results typically within ±20%. Speed depends on batch size, quantization kernel, and software stack.
What's the download size of JiRackUltra 1B?
At Q4_K_M, the download is about 1.07 GB. The full-precision BF16 version is 3.55 GB. The smallest option (IQ2_XXS) is 0.49 GB.
Which GPUs can run JiRackUltra 1B?
52 consumer GPUs can run JiRackUltra 1B at Q4_K_M. Top options include AMD Radeon RX 6700 XT, AMD Radeon RX 6800, AMD Radeon RX 6800 XT. 52 GPUs have plenty of headroom for comfortable inference.
Which devices can run JiRackUltra 1B?
163 devices with unified memory can run JiRackUltra 1B at Q4_K_M (1.4 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.