M5 Ultra / M5 Max vs M3 Ultra: 38 Days After Upgrading, Should I Upgrade Again?
M5 Ultra／M5 Max Mac Studio 上架了。頻寬 +47%，但今年缺 RAM，記憶體實際只賣到 256GB；而且「效能核心」這個詞在 M5 上換了意思。三台對照、附官方截圖，以及我為什麼決定不換。
The M5 Ultra and M5 Max Mac Studios are live. Bandwidth up 47% — but this year's RAM shortage caps what you can actually buy at 256GB, and the phrase "performance core" changed meaning on M5. Three machines compared, with Apple's own screenshots, and why I'm not upgrading.
硬體 · HardwareHardwareMac Studio本地 AILocal AI
七月十九號，我寫了一篇換上 M3 Ultra Mac Studio 的升級筆記。那篇裡我抱怨了一格：記憶體頻寬從 M2 Ultra 的 800GB/s 到 M3 Ultra 的 819GB/s，「只是微幅提升」，這代的甜頭是放得下、不是餵得更快。
On July 19 I wrote upgrade notes for the M3 Ultra Mac Studio. In it I complained about one row: memory bandwidth went from 800GB/s on M2 Ultra to 819GB/s on M3 Ultra — "a rounding-error bump." The win that generation was fitting the model, not feeding it faster.
Thirty-eight days later, Apple filled that row in. M5 Ultra runs 1.2TB/s of memory bandwidth. As for capacity — the spec page lists 512GB, but this year's RAM shortage means the most you can actually buy is 256GB (my July M3 Ultra had it worse: 96GB was the only option, period). This isn't a buyer's-remorse post — it's a comparison and a decision: three machines side by side, Apple's own screenshots, one core-naming trap that's very easy to misread, and finally the practical question — should I upgrade again?
三台攤開對照：M3 Ultra ／ M5 Max ／ M5 Ultra
Three Machines Side by Side: M3 Ultra / M5 Max / M5 Ultra
規格Spec
M3 Ultra 2025 · 我在用in use
M5 Max 2026 · 全新new
M5 Ultra 2026 · 全新new
CPU 核心（起／最多）CPU cores (base / max)
28 / 32
18 / 18
30 / 36 ↑
CPU 組成（最高配）CPU makeup (max config)
24 效能 ＋ 8 節能24 perf + 8 efficiency
6 超級 ＋ 12 效能6 super + 12 perf-named
12 超級 ＋ 24 效能12 super + 24 perf-named
GPU 核心（起／最多）GPU cores (base / max)
60 / 80
32 / 40
64 / 80 ＝
神經網路引擎Neural Engine
32 核心cores
16 核心cores
32 核心cores＝
神經網路加速器Neural accelerators
—
✓
✓ 新
硬體光線追蹤Hardware ray tracing
✓
✓
✓ ＝
記憶體頻寬Memory bandwidth
819 GB/s
最高 614 GB/sup to 614 GB/s
1.2 TB/s ↑↑
統一記憶體（實際買得到）Unified memory (actually orderable)
96GB （唯一選項）(only option)
36 / 48 / 64 / 128GB
96 / 256GB ↑
SSD（起／最高）SSD (base / max)
1TB / 16TB
512GB / 8TB
1TB / 16TB ＝
影片解／編碼 · ProResVideo decode / encode · ProRes
2 / 4 · 4
1 / 2 · 2
2 / 4 · 4 ＝
AV1 解碼AV1 decode
✓
✓
✓ ＝
Thunderbolt 5
6
4（＋2 個 USB-C）4 (+2 USB-C)
6 ＝
Wi-Fi / 藍牙Bluetooth
6E / 5.3
7 / 6
7 / 6 ↑
台灣售價（起）Price in TW (from)
已停售discontinued
NT$84,900
NT$199,900
資料整理自 Apple 官網 Mac Studio 比較頁，擷取日期 2026-08-26（原始截圖見下一節）。我實際在用的是 M3 Ultra 96GB／4TB；M3 Ultra 在這個比較頁上已不再顯示售價，等同退出現售陣容。記憶體那一列寫的是實際下得了單的容量——比較頁上 M5 Ultra 另有一個 512GB 選項，但今年缺 RAM，選購頁最高只到 256GB。↑ 表示對 M3 Ultra 提升、＝ 表示持平。CPU 那兩列請先別急著比大小——下面有一節專門講。
Compiled from Apple's official Mac Studio compare page, captured 2026-08-26 (original screenshots in the next section). The machine I actually run is an M3 Ultra 96GB / 4TB; M3 Ultra no longer shows a price on that page, meaning it's out of the current lineup. The memory row lists what you can actually order — the compare page shows a 512GB option for M5 Ultra, but with this year's RAM shortage the configurator tops out at 256GB. ↑ = gain over M3 Ultra, ＝ = unchanged. Don't compare those two CPU rows by number yet — there's a whole section on that below.
Apple 官方規格對照（原始截圖 · 2026-08-26）
Apple's Official Comparison (Original Screenshots · 2026-08-26)
上面那張表是我自己整理的重點；下面直接附上 2026-08-26 從 Apple 官網 Mac Studio 比較頁擷取的原始畫面——核心數、記憶體與儲存選項、無線與連接埠、以及台灣售價，一切以 Apple 官網最新公告為準。
The table above is my own summary; below are the raw screenshots captured 2026-08-26 from Apple's Mac Studio compare page — core counts, memory and storage options, wireless and ports, and pricing in TWD. Apple's site is the source of truth.
現售陣容：M5 Ultra NT$199,900 起、M5 Max NT$84,900 起，兩台都標「全新」；M3 Ultra 已無售價。Current lineup: M5 Ultra from NT$199,900, M5 Max from NT$84,900, both flagged "New"; M3 Ultra shows no price.起始規格：M5 Ultra 30 核 CPU／64 核 GPU／96GB／1TB；M5 Max 18 核／32 核／36GB／512GB；M3 Ultra 28 核／60 核／96GB／1TB。Base configs: M5 Ultra 30-core CPU / 64-core GPU / 96GB / 1TB; M5 Max 18 / 32 / 36GB / 512GB; M3 Ultra 28 / 60 / 96GB / 1TB.系統單晶片與媒體引擎：這一張最關鍵——記憶體頻寬 1.2TB/s ／ 614GB/s ／ 819GB/s，以及 M5 才有的「神經網路加速器」那一行。SoC and media engine — the key screenshot: 1.2TB/s vs 614GB/s vs 819GB/s of bandwidth, plus the "neural accelerators" line only M5 has.記憶體與儲存：這張頁面列出 M5 Ultra 96／256／512GB（512GB 需搭 80 核 GPU），但實際選購最高只到 256GB；M5 Max 36／48／64／128GB、M3 Ultra 僅 96GB。Memory & storage: this page lists 96/256/512GB for M5 Ultra (512GB requires the 80-core GPU), but the configurator only goes to 256GB; M5 Max 36/48/64/128GB, M3 Ultra 96GB only.無線與連接埠：M5 兩台都是 Wi-Fi 7 ／ 藍牙 6；M3 Ultra 停在 Wi-Fi 6E ／ 藍牙 5.3。Thunderbolt 5 三台都有。Wireless & ports: both M5 machines get Wi-Fi 7 / Bluetooth 6; M3 Ultra stays on Wi-Fi 6E / Bluetooth 5.3. All three have Thunderbolt 5.實際選配的樣子：M5 Ultra 30 核 CPU／64 核 GPU、256GB 記憶體 ＋ 4TB SSD＝NT$358,640（含教育優惠），運送狀態「暫無供應」。What a real config costs: M5 Ultra 30-core CPU / 64-core GPU, 256GB memory + 4TB SSD = NT$358,640 (with education pricing), shipping status "currently unavailable."
M1 Ultra 800, M2 Ultra 800, M3 Ultra 819 — three generations of essentially the same number. M5 Ultra jumps to 1.2TB/s, 47% above M3 Ultra. For anyone running local models, this is the heaviest row on the sheet: generation speed is roughly proportional to "memory bandwidth ÷ model size", so a 47% bandwidth gain lifts token throughput on the same model by roughly the same margin.
In everyday terms: a 4-bit quantised 70B model takes about 40GB, so the theoretical ceiling is 819÷40 ≈ 20 tok/s on M3 Ultra and 1200÷40 ≈ 30 tok/s on M5 Ultra. Real numbers usually land at 60–80% of theory, but the ratio holds — and for the first time an Ultra-generation upgrade actually shortens the wait for a reply, instead of only enlarging what fits.
💡 M5 Max 的 614GB/s 也值得看兩眼💡 M5 Max's 614GB/s deserves a second look：它是 M3 Ultra 819GB/s 的 75%，但價格是 NT$84,900 起——不到 M3 Ultra 當年 NT$184,900 的一半。這件事後面有一整節。: that's 75% of M3 Ultra's 819GB/s, at NT$84,900 — less than half the NT$184,900 the M3 Ultra started at. There's a whole section on this below.
② 記憶體天花板 256GB：今年缺 RAM，兩代的頂規都被壓住了
② The 256GB Ceiling: A RAM Shortage Capped Both Generations
Apple 比較頁上，M5 Ultra 的記憶體欄位列了 96／256／512GB 三個選項。但真的走進選購頁下訂，買得到的最高是 256GB——512GB 那一格是規格上限，不是貨架上的商品。原因不在產品線設計，在於 2026 年整個產業的記憶體供給吃緊。
On Apple's compare page, M5 Ultra's memory field lists three options: 96 / 256 / 512GB. But walk into the configurator and actually place an order, and the most you can buy is 256GB — that 512GB entry is a spec ceiling, not something on the shelf. The reason isn't product-line design; it's how tight industry-wide memory supply is in 2026.
And it isn't the first time. The M3 Ultra I bought in July had exactly one memory option: 96GB — the silicon could take more in principle, but a shortage is a shortage, and the top config sat there. So this generation's real memory story isn't "up to 512GB"; it's that the practical ceiling rose from 96GB to 256GB, 2.7×. That still carries weight — but you need the ceiling right before matching it against the model sizes below.
70B 級（約 40GB）— 96GB 就放得下，M5 Ultra 理論 ~30 tok/s，對話順暢70B class (~40GB) — fits in 96GB; ~30 tok/s theoretical on M5 Ultra, comfortably conversational好用usable
120B 級（約 61GB）— 96GB 勉強、256GB 從容，理論 ~20 tok/s120B class (~61GB) — tight in 96GB, roomy in 256GB; ~20 tok/s theoretical好用usable
235B 級（約 130GB）— 這就是 256GB 買到的東西：我的 96GB 連載入都不行，256GB 進得去，理論 ~9 tok/s235B class (~130GB) — this is what 256GB buys: my 96GB can't even load it; 256GB can, at ~9 tok/s theoretical堪用tolerable
670B 級（約 400GB）— 256GB 放不下。規格頁那個 512GB 才裝得進去，但今年買不到——這一級在桌機上還是做不到670B class (~400GB) — doesn't fit in 256GB. The 512GB on the spec page would hold it, but you can't buy that this year — this tier stays out of reach on a desktop買不到unavailable
所以 256GB 真正買到的東西很具體：把 235B 級的模型從「載不進來」變成「載得進來」。這一步很大——它決定的是能不能做，不是快不快。但也別把它想成無限：670B 那一級，這代在 Mac Studio 上依然做不到，不是因為晶片不行，是因為那個容量今年下不了單。
So what 256GB actually buys is concrete: it turns a 235B-class model from "won't load" into "loads." That's a big step — it decides what's possible, not how fast. But don't mistake it for unlimited: the 670B tier still can't run on a Mac Studio this generation, not because the chip can't, but because that capacity can't be ordered this year.
The other visible side effect is price. M5 Ultra starts at NT$199,900, NT$15,000 above the NT$184,900 my M3 Ultra started at in July. With memory tight across the board, that NT$15,000 probably isn't all performance.
⚠️ 上面全是理論上限⚠️ These are all theoretical ceilings：實際 tok/s 會受量化方式、推論框架、context 長度、以及系統本身佔用的記憶體影響，通常落在理論值的六到八成。這些數字用來排序機型很好用，拿來當效能承諾就不行。等真機評測出來，一切以實測為準。另外，供貨狀況隨時會變——能買到多大的記憶體，請以你下訂當天的 Apple 選購頁為準。: real tok/s depends on quantisation, inference framework, context length, and the memory the OS itself holds — typically 60–80% of theory. These numbers are good for ranking machines, not as performance promises. Once real reviews land, trust the measurements. Supply also moves — for how much memory you can actually get, check Apple's configurator on the day you order.
③ 最容易看錯的一格：M5 的「效能核心」不是 M3 的「效能核心」
③ The Easiest Row to Misread: "Performance Core" Changed Meaning
這是我在官方截圖裡看到、覺得最該提醒的一件事。Apple 在 M5 世代換掉了 CPU 核心的稱呼，於是同樣四個字在兩代表格上指的是不同的東西：
This is the thing in Apple's own screenshots I most want to flag. Apple renamed the CPU core tiers in the M5 generation, so the same words mean different things across the two spec sheets:
M3 Ultra · 官方原文· as printed
最多可達 32 核心 CPU 配備 24 個效能核心 與 8 個節能核心
Up to 32-core CPU with 24 performance cores and 8 efficiency cores
M5 Ultra · 官方原文· as printed
最多可達 36 核心 CPU 配備 12 個超級核心 與 24 個效能核心
Up to 36-core CPU with 12 super cores and 24 performance cores
See it? On M3 Ultra the high-power tier is called "performance cores"; on M5 Ultra the high-power tier is renamed "super cores," and the name "performance cores" slides down to the low-power tier. So:
Total cores: 32 → 36, up. But if you line up the high-power tier under the old definition, M3 Ultra has 24 and M5 Ultra has just 12 super cores. On the raw number, that's a halving.
⚠️ 我不會直接說「M5 Ultra 編譯比較慢」⚠️ I'm not going to claim "M5 Ultra compiles slower"：一顆 M5 超級核心的單核效能顯然不是一顆 M3 效能核心可以比的，而且 M5 的「效能核心」也不是老式的節能小核。但 Xcode clean build、平行跑多台模擬器這類工作，吃的是大核的數量——12 對 24 是個值得放在心上的問號。這一格只能等實測，規格表回答不了。: a single M5 super core is clearly not comparable to a single M3 performance core, and M5's "performance cores" aren't old-style little efficiency cores either. But Xcode clean builds and running several simulators in parallel feed on the count of big cores — 12 vs 24 is a question worth holding onto. This row can only be settled by benchmarks; the spec sheet can't answer it.
④ 官方多了一行：「神經網路加速器」
④ One New Line on the Sheet: "Neural Accelerators"
In the SoC screenshot, both M5 Ultra and M5 Max carry a line M3 Ultra doesn't: "neural accelerators." Meanwhile the Neural Engine count is unchanged — 32 cores on both M5 Ultra and M3 Ultra. So this is an additional set of units alongside the Neural Engine, not the old one getting faster.
Apple's compare page gives the phrase and no numbers, so I won't invent a multiplier for it. Two things are certain: M3 Ultra doesn't have it, and it appears on both M5 Ultra and the cheapest M5 Max — even the NT$84,900 entry machine. The actual benefit waits on measurements, especially for the matrix-heavy stage of local inference.
All eyes are on M5 Ultra, but run the "local-AI capability per dollar" arithmetic and the answer is M5 Max. It has 614GB/s of bandwidth (75% of M3 Ultra's), an optional 128GB of unified memory (33% more than the 96GB on this compared M3 Ultra; again, check the configurator on the day), Wi-Fi 7, four Thunderbolt 5 ports, and the M5 generation's neural accelerators.
It starts at NT$84,900. The M3 Ultra I bought in July started at NT$184,900 and now shows no price on this page at all. Less than half the money for three-quarters of the bandwidth and a higher memory ceiling — for the specific need of "a desktop that runs 70B–120B models locally," an M5 Max with 128GB is probably the most practical machine on offer.
🧊 它讓掉的是什麼🧊 What it gives up：CPU 只有 18 核（Ultra 是 36）、GPU 最多 40 核（Ultra 80）、神經網路引擎 16 核（Ultra 32）、影片編解碼引擎只有一半、Thunderbolt 5 少兩個、SSD 最高 8TB。如果你的瓶頸是 Xcode 編譯、影片輸出、或一次接一整牆的螢幕，那 Ultra 的錢還是有它的道理。: 18 CPU cores (vs 36), up to 40 GPU cores (vs 80), a 16-core Neural Engine (vs 32), half the video encode/decode engines, two fewer Thunderbolt 5 ports, and an 8TB SSD ceiling. If your bottleneck is Xcode builds, video exports, or driving a wall of displays, the Ultra premium still earns its keep.
The blunt part first: an M5 Ultra with 30-core CPU / 64-core GPU, 256GB and 4TB, costs NT$358,640 (education pricing, see the configurator screenshot above) — and 256GB is already the most memory you can buy this year; there is no rung above it. With shipping listed as "currently unavailable," that price is nearly twice what I paid 38 days ago.
但真正讓我按住手的不是價錢，是上一篇寫的那件事：我的產出來自雙機分工——M3 Ultra 跑生成與審查、M1 Max 跑爬蟲、檢索、備份與風險沙盒。而我目前卡住的地方，從來不是 tok/s，是「今天要做哪個 App」。頻寬多 47% 不會幫我決定這件事。
But what actually stays my hand isn't the price — it's the thing the last post was about: my output comes from a two-machine split — M3 Ultra generates and reviews, M1 Max crawls, retrieves, backs up, and sandboxes risk. And what I'm actually stuck on has never been tok/s; it's deciding which app to build today. 47% more bandwidth doesn't decide that.
My upgrade test hasn't changed: find the row you're actually stuck on, then decide whether to pay for that row. In July I was stuck on memory — models wouldn't load — so that money was well spent. I'm not stuck on bandwidth today. And on the memory row, 256GB beats 96GB but it's a ceiling forced by a shortage, not a design endpoint: when supply loosens, the same money should buy more. All the more reason not to rush.
Then it's an M5 Max with 128GB, no hesitation. Under the same logic that already governs my pair — assign model size by memory bandwidth — the M5 Max slots neatly into the middle tier: 614GB/s is enough to keep a 70B model resident as a second reviewer, 128GB is roomier than the M3 Ultra's 96GB, and it costs a little over 40% of an M5 Ultra. Incidentally, I already bought the Thunderbolt 5 cable back then — a third machine would finally run it at the full 120Gb/s. No new cable needed.
M5 Ultra is worth considering if: you need to load 235B-class models locally (256GB is a rare desktop answer), your income is tied directly to inference throughput, or you're also a heavy video professional who needs those four ProRes engines. If what you're waiting for is 512GB, though, you're just waiting on supply — it can't be ordered right now.
M5 Max 是甜蜜點：你想要一台安靜的桌機跑 70B～120B 本地模型、寫 code、偶爾剪片。NT$84,900 起、128GB 可選——這是這次發表裡 CP 值最高的一台。
M5 Max is the sweet spot if: you want one quiet desktop that runs 70B–120B models locally, writes code, and edits video occasionally. From NT$84,900 with a 128GB option — the best value in this launch.
You can wait if: you're on an M3/M4 Ultra and bandwidth or the memory ceiling isn't what's blocking you. This generation's GPU ceiling (80 cores), Neural Engine (32 cores), storage ceiling (16TB), and Thunderbolt 5 count all match M3 Ultra — and the 12-vs-24 big-core question has no benchmark answer yet. Add a memory shortage capping the top config at 256GB and a NT$15,000 higher entry price, and waiting for the first reviews — and for supply to ease — costs you nothing.
收工筆記Closing note 三十八天前我買了 M3 Ultra，三十八天後 M5 Ultra 上架。這種事在 2026 年不會是最後一次——所以我學到的不是「早知道等一下」，而是不要用發表週期來安排自己的工作。硬體會一直往前，卡住產出的通常是別的東西。這代還多了一課：規格頁上的數字和你真的下得了單的數字是兩回事，缺貨年尤其如此——我那台只賣 96GB，這台只賣到 256GB，兩次都是被同一件事壓住的。真正該記住的只有那個判準：先找出自己卡在哪一格，再決定要不要為那格付錢。這次我卡的不是頻寬，所以我留著 M3 Ultra，繼續做 App。I bought an M3 Ultra thirty-eight days ago; thirty-eight days later the M5 Ultra went on sale. This won't be the last time that happens in 2026 — so what I take from it isn't "should have waited," it's don't schedule your work around launch cycles. Hardware keeps moving; what blocks output is usually something else. This generation added a second lesson: the number on the spec page and the number you can actually order are two different things, especially in a shortage year — mine sold only 96GB, this one sells only up to 256GB, both pinned by the same thing. The only thing worth keeping is the test: find the row you're actually stuck on, then decide whether to pay for that row. This time it isn't bandwidth — so I'm keeping the M3 Ultra and getting back to shipping apps.
