Apple's 512 GB Mac Studio is orderable now: $22,299.
The 256 GB version of the same M5 Ultra chip is $10,799. So what does the second 256 GB buy?
At 256K of context, by our calculator, mostly better copies of the same models:
MiniMax M3.1 Flash: Q2_K on 256 GB, Q8_0 on 512
GLM 5.3 Flash: Q3_K_M, then Q8_0
Ornith 1.5 397B: Q3_K_M, then Q6_K
Qwen 3.8 Flash Next: Q5_K_M, then Q8_0
And the 550B to 1T class moves in: DeepSeek V4.1 Flash 1017, GLM 5.3, Kimi K2.6 and Inkling 975B, whole, in memory, at 256K. 73 models fit against 58.
One thing to know before you pay: Strata's own Mac plan runs DeepSeek 1017 at 2 bits with every expert in memory on the 256 GB model too. It reads the lookup tables from the SSD.
Speed on this chip: DeepSeek 1017 at 54.5 tok/s (256 GB M5 Ultra, ds4, tested to 128K,
@niklaslenz_ai). The weak side is prompts: 1,475 tok/s reading a 32K one.
We sized this Mac in September, before it shipped. The second image is a page of Issue 1: every model we size, on eight machines. Issue 2, out 31 October, has the full launch dossier, and Issue 1 comes with it.
Long chats and code, or long prompts all day: which is your workload?
vramcalculator.com/sizing-gu…