MacBook Pro M5 Max (16-inch): 48GB vs 128GB for local AI
The MacBook Pro M5 Max (16-inch), 128GB holds 41 of the 50 current models here, and the MacBook Pro M5 Max (16-inch), 48GB holds 34. The MacBook Pro M5 Max (16-inch), 48GB costs $2,000 less. On Qwen3.8 27B, the strongest model both hold, they run at much the same speed: 25 and 25 tok/s, both estimated from memory bandwidth. The MacBook Pro M5 Max (16-inch), 48GB pays for itself sooner, in 281 years against 393 years at 500k tokens a day.
| MacBook Pro M5 Max (16-inch), 48GB | MacBook Pro M5 Max (16-inch), 128GB | |
|---|---|---|
| Price | $4,999 | $6,999 |
| Memory | 48 GB | 128 GB |
| Usable by the GPU | 36 GB | 96 GB |
| Memory bandwidth | 614 GB/s | 614 GB/s |
| Power under load | 145 Wstand-in | 145 Wstand-in |
| Models that fit | 34 | 41 |
| Best model it runs | Qwen3.8 27B | Qwen3.8 27B |
| Speed on that model | 25 tok/s estimated | 25 tok/s estimated |
| Pay-back on that model | Pays back in 281 years | Pays back in 393 years |
Neither power figure above is measured on the machine beside it. Both are stand-ins borrowed from the nearest hardware the data does have, so what the row shows is one borrowed figure printed twice. Each machine's page names the figure it borrows and why. Every pay-back figure on this page prices its electricity from these numbers.
Run the numbers on the MacBook Pro M5 Max (16-inch), 48GB · or the MacBook Pro M5 Max (16-inch), 128GB
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 MacBook Pro M5 Max (16-inch), 48GB 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 use | MacBook Pro M5 Max (16-inch), 48GB | MacBook Pro M5 Max (16-inch), 128GB |
|---|---|---|
| 50ka few chats a day | 2,811 years | 3,935 years |
| 200klight assistant use | 703 years | 984 years |
| 1Ma moderate coding-assistant day | 141 years | 197 years |
| 4Mheavy coding with an agent | 35 years | 49 years |
| 20Magents running most of the day | 7.0 years | 9.8 years |
Run the MacBook Pro M5 Max (16-inch), 48GB at 20M tokens a day · or the MacBook Pro M5 Max (16-inch), 128GB
What the extra memory buys
The MacBook Pro M5 Max (16-inch), 128GB holds 7 models the MacBook Pro M5 Max (16-inch), 48GB cannot at 32k of context. The strongest of them are what the difference in memory actually buys.
| Model | Weights | Needs at 32k | On the MacBook Pro M5 Max (16-inch), 128GB |
|---|---|---|---|
| Ling 3.0 flashHaiku-class | 78 GB | 78 GB | 53 tok/s estimated |
| Qwen3.5 122B-A10BHaiku-class | 78 GB | 79 GB | 26 tok/s estimated |
| gpt-oss-120bBelow every hosted tier | 63 GB | 65 GB | 46 tok/s estimated |
| Mistral Small 4 (119B-2603)Below every hosted tier | 74 GB | 75 GB | 41 tok/s estimated |
| Qwen3-Coder NextBelow every hosted tier | 48 GB | 49 GB | 70 tok/s estimated |
| Devstral 2 123BBelow every hosted tier | 75 GB | 87 GB | 5.3 tok/s estimated |
1 more, on the MacBook Pro M5 Max (16-inch), 128GB page.
The extra memory buys context as well. Of the 34 current models both machines hold at 32k, 7 run to a longer window on the MacBook Pro M5 Max (16-inch), 128GB: the weights are a fixed size and the KV cache is not, so what the weights leave spare is what a longer context grows into. Nanbeige4.3 33B reaches 256k there against 64k on the MacBook Pro M5 Max (16-inch), 48GB, each the longest window the calculator offers that the machine still holds it at.
The MacBook Pro M5 Max (16-inch), 48GB is also head to head with another computer: Mac Studio M5 Max, 128GB. With the same machine at another memory size: 64GB.
The MacBook Pro M5 Max (16-inch), 128GB is also head to head with the same machine at another memory size: 64GB.
Both sizes have a page of their own, with every machine here sold at that size, the models that fit it and what one step of memory buys: what 48 GB runs · what 128 GB runs.
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. Change any of it in the calculator.
More head to head: everything the MacBook Pro M5 Max (16-inch), 48GB runs · everything the MacBook Pro M5 Max (16-inch), 128GB runs · every other match-up · the quickest pay-back at each level of use · every model against the frontier