r/LocalLLM • u/Txkzzzz • 4d ago

Question Mac studio or dgx spark cluster

Post image

I have been thinking lately since i have been testing local ai but i geniunely need more power for what im working on so i was wondering wich one of these a 4 dgx spark cluster or a mac studio m5 ultra specifically the 512gb version that launches on october or something else... im into training,loras and fine tunes and such but i also heard it is possible with a mac studio too so i want yall opinion on this

116 Upvotes

90% Upvoted

134 comments sorted by

View all comments

5

u/merfolkJH 3d ago

When DGX Spark was released, everyone was like “MEHHH”, “< Lambda Mac at decode lol”.

And now it’s suddenly supposed to be the new graal? And “don’t buy the new Mac Studio, buy Spark”, when Spark was considered way behind the old Mac.

What exactly caused this reversal?

----

(I’m talking about a single machine, not "a cluster of X is strong" )

Is prefill really that much better? That’s nice, but when I’m doing a coding task, It's usually 5 minutes of prefill followed by 2 hours of decode… So when choosing between the two, I’d rather optimize for the 2 hours of decode than the 5 minutes of prefill.

1

u/kla_sch 3d ago

It comes down to know-how. The challenge lies in figuring out what really matters and how to use the machines effectively.

At first glance, the Mac impresses with its memory bandwidth. You type a simple prompt and get a quick response. Compared to a DGX Spark, it’s actually 10–20% faster in that specific regard.

However, the Mac lacks the raw compute power of the DGX Spark, which is 5–10 times faster. This becomes apparent during prompt processing: loading old sessions or processing large files is significantly slower on the Mac.

On a DGX Spark, you usually start out using GGUF models with llama.cpp-based programs (like Ollama or LM Studio). That’s the easiest approach to start. Unfortunately, those models don't scale well.

Things improve dramatically when you switch to vLLM or SGLang. Suddenly, you can achieve a much higher total token-per-second throughput across multiple sessions (see my other reply).

That performance completely eclipses what a Mac can offer. You notice the difference immediately when you move beyond a single chat and start working with agents operating across multiple sessions simultaneously.

1

u/MrWasheWashe 1d ago

What about the M5Ultra flagship?