Sunk Cost sunkcost.ai Data checked 2026-09-03

Mac mini M4 Pro vs M5 Pro, 64GB for local AI

Both hold 27 of the 39 open models here. The Mac mini M4 Pro, 64GB costs $700 less. On Qwen3.8 27B, the strongest model both hold, the Mac mini M5 Pro, 64GB is about 1.1× faster: 12 tok/s against 11, both estimated from memory bandwidth. The Mac mini M4 Pro, 64GB pays for itself sooner, in 26 years against 35 years at 500k tokens a day. The Mac mini M4 Pro, 64GB is the previous generation, so every figure here for it is priced at what it launched at rather than at a price you can pay today.

Mac mini M4 Pro, 64GBMac mini M5 Pro, 64GB
Price$1,999$2,699
Memory64 GB64 GB
Usable by the GPU48 GB48 GB
Memory bandwidth273 GB/s307 GB/s
Power under load140 W140 Wstand-in
Models that fit2727
Best model it runsQwen3.8 27BQwen3.8 27B
Speed on that model11 tok/s estimated12 tok/s estimated
Pay-back on that modelPays back in 26 yearsPays back in 35 years

Run the numbers on the Mac mini M4 Pro, 64GB · or the Mac mini M5 Pro, 64GB

What the newer chip buys

These are the same machine a generation apart, in the same case and at the same memory size, so this is the upgrade question rather than a choice between two things on sale. What separates them is bandwidth: the M5 Pro reads its memory at 307 GB/s where the M4 Pro reads it at 273. Decoding reads the whole model out of memory for every token it writes, so that is the figure the speeds in the table follow. The M5 Pro here is listed as 15-core CPU / 16-core GPU, against the M4 Pro's 12-core CPU / 16-core GPU.

The two power figures are equal for a reason that is not about either machine: Apple has not published one for the M5 Pro, so the data stands the M4 Pro's published 140 W in for it and this page prices the electricity into both columns from that. Read it as a placeholder, not as a finding that the newer chip draws the same.

Apple stopped selling the Mac mini M4 Pro, 64GB on 25 August 2026, so the $1,999 above is the price it launched at, and every figure on this page for it is priced at that. A used or refurbished one costs whatever it costs, and pay-back follows the price rather than the machine. Open the calculator on the Mac mini M4 Pro, 64GB and put in what you would actually pay; the years move with it. Its own page has what the data records about buying one now.

How much use it takes to pay back

Everything above is at 500k tokens a day. Pay-back moves with how much you actually run, so here are both machines on Qwen3.8 27B, the strongest model both hold, at the five levels of use the calculator names. The Mac mini M4 Pro, 64GB pays back sooner at every level of use, so this is not a choice that turns on how hard you work it.

A day's useMac mini M4 Pro, 64GBMac mini M5 Pro, 64GB
50ka few chats a day261 years350 years
200klight assistant use65 years87 years
1Ma moderate coding-assistant day13 years17 years
4Mheavy coding with an agent3.3 years4.4 years
20Magents running most of the day10 monthsits ceiling12 monthsits ceiling

On Qwen3.8 27B neither machine can generate 20M tokens a day: the Mac mini M4 Pro, 64GB manages at most 15.2M and the Mac mini M5 Pro, 64GB at most 17.1M. Both figures on that row are for the most each can do.

Run the Mac mini M4 Pro, 64GB at 20M tokens a day · or the Mac mini M5 Pro, 64GB

Memory is not what separates them

Every model on this list that fits one machine fits the other, and not only at 32k of context: across all 39 models the calculator counts, at every context from 4k to 256k, there is no model one holds and the other does not. Both leave 48 GB to the GPU. So the choice between them is speed, price and power, not what they can hold.

The assumptions behind both columns

Both columns use the same usage: 500k tokens a day at 15:1 input to output, 32k of context, $0.17 per kWh, and today's API prices held flat. Speeds marked estimated are worked out from memory bandwidth rather than measured, and pay-back scales with them. Graphics cards are priced as the card alone, so add the PC around one before comparing it with a complete computer. Change any of it in the calculator.

More head to head: everything the Mac mini M4 Pro, 64GB runs · everything the Mac mini M5 Pro, 64GB runs · every other match-up · the quickest pay-back at each level of use · every model against the frontier