Is unified memory on Mac Studio M1 Ultra 128GB as fast as VRAM for Yi Coder 1.5B Chat?

Not always. Mac Studio M1 Ultra 128GB can often fit larger models thanks to unified memory, but a discrete GPU with dedicated high-bandwidth VRAM may still decode faster once the model fits. For this combination, the important distinction is capacity versus sustained throughput.

Can Yi Coder 1.5B Chat run on Mac Studio M1 Ultra 128GB?

YES — Runs Great

C41Usable

Estimated from fit model

Yi Coder 1.5B Chat needs ~15.8 GB VRAM. Mac Studio M1 Ultra 128GB has 92.2 GB. With Q4_K_M quantization, expect ~21 tok/s.

Runtime: llama.cppCapacity: RoomyBandwidth: HighStack: StandardBottleneck: Balanced

Operating mode

Choose the run profile you care about

Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.

Current mode

Balanced

Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.

Capabilities:

Select quantization to explore

Q4_K_M (Medium quality) — 15.8 GB, 21.0 tok/s, Runs well

15.8 GB required92.2 GB available

17% VRAM used

Fit status

Runs well

Decode

21.0 tok/s

TTFT

9219 ms

Safe context

7.0M

Memory

15.8 GB / 92.2 GB

Memory breakdown

Weights0.9 GB

KV Cache0.2 GB

Runtime0.9 GB

Headroom13.8 GB

See how fast it feels

See how fast it feelsYi Coder 1.5B Chat on Mac Studio M1 Ultra 128GB
1st promptCold start — includes initialization
>Write a Python function to sort a list
Here's a Python function that sorts a list using quicksort:

def quicksort(arr):
    if len(arr) <= 1:
        return arr
    pivot = arr[len(arr) // 2]
    left   = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right  = [x for x in arr if x > pivot]
    return quicksort(left) + middle + quicksort(right)

# Example usage
numbers = [3, 6, 8, 10, 1, 2, 1]
print(quicksort(numbers))  # [1, 1, 2, 3, 6, 8, 10]

The algorithm picks a pivot, partitions the list into smaller, equal, and larger elements, then recursively sorts each partition and concatenates the results.
2nd promptWarm — model ready, no init overhead
>Now add type hints and a docstring
def quicksort(arr: list[int]) -> list[int]:
    """Sort a list using the quicksort algorithm.

    Args:
        arr: List of integers to sort.

    Returns:
        A new sorted list.
    """
    if len(arr) <= 1:
        return arr
    pivot = arr[len(arr) // 2]
    left   = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right  = [x for x in arr if x > pivot]
    return quicksort(left) + middle + quicksort(right)

Added type hints for the input and return type, plus a Google-style docstring.
Estimated: 21.0 tok/s decode · 9.2s TTFT (warm) · 53 tok/s prefill

What limits this setup

This setup is broadly balanced for this model.

Shared-memory contention still exists

The OS, browser, and inference runtime all compete for the same physical memory pool, so real-world headroom is less forgiving than raw capacity suggests.

Best improvement path

Performance by workload

Workload	Grade	Fit	Decode	TTFT	Context
Chat	C	Runs well	21.0 tok/s	5029 ms	6.1M
Coding	C	Runs well	21.0 tok/s	9219 ms	7.0M
Agentic Coding	C	Runs well	21.0 tok/s	13410 ms	7.0M
Reasoning	C	Runs well	21.0 tok/s	10895 ms	7.0M
RAG	C	Runs well	21.0 tok/s	16762 ms	7.0M

Quantization options

How Yi Coder 1.5B Chat (1.5B params) fits at each quantization level on Mac Studio M1 Ultra 128GB (92.2 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	0.6 GB	Low	D39
Q3_K_S	3	0.7 GB	Low	D39
NVFP4	4

Get started

Copy-paste commands to run Yi Coder 1.5B Chat on your machine.

Run

lms load hf-maziyarpanahi--yi-coder-1-5b-chat-gguf && lms server start

Frequently asked questions

Can Mac Studio M1 Ultra 128GB run Yi Coder 1.5B Chat?

Yes, Mac Studio M1 Ultra 128GB can run Yi Coder 1.5B Chat with a C grade (Runs well). Expected decode speed: 21.0 tok/s.

How much VRAM does Yi Coder 1.5B Chat need?

Yi Coder 1.5B Chat (1.5B parameters) requires approximately 15.8 GB of memory with Q4_K_M quantization.

What is the best quantization for Yi Coder 1.5B Chat?

The recommended quantization for Yi Coder 1.5B Chat is Q4_K_M, which balances quality and memory efficiency.

What speed will Yi Coder 1.5B Chat run at on Mac Studio M1 Ultra 128GB?

On Mac Studio M1 Ultra 128GB, Yi Coder 1.5B Chat achieves approximately 21.0 tokens per second decode speed with a time-to-first-token of 9219ms using Q4_K_M quantization.

Can Mac Studio M1 Ultra 128GB run Yi Coder 1.5B Chat for coding?

For coding workloads, Yi Coder 1.5B Chat on Mac Studio M1 Ultra 128GB receives a C grade with 21.0 tok/s and 7.0M context.

What context window can Yi Coder 1.5B Chat use on Mac Studio M1 Ultra 128GB?

On Mac Studio M1 Ultra 128GB, Yi Coder 1.5B Chat can safely use up to 7.0M tokens of context. The model's official context limit is —, but available memory constrains the safe maximum.

See all results for Mac Studio M1 Ultra 128GB See all hardware for Yi Coder 1.5B Chat

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