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

Qwen3.5 4B vs gpt-oss-120b

Qwen3.5 4B scores higher on the intelligence index, 13 against 12. The cheapest machine here that runs gpt-oss-120b is the Framework Desktop, 128GB, at $3,449. Qwen3.5 4B runs on the Mac mini M6, 16GB at $899, $2,550 less. On the Framework Desktop, 128GB, the cheapest machine here that runs both, Qwen3.5 4B is about 1.4× quicker: 50 tok/s against 35, gpt-oss-120b's measured and the other estimated from memory bandwidth. At 500k tokens a day the Framework Desktop, 128GB pays for itself in 327 years running Qwen3.5 4B, against 720 years running gpt-oss-120b.

Qwen3.5 4Bgpt-oss-120b
Intelligence index1312
ClassBelow every hosted tierBelow every hosted tier
Weights2.7 GB63 GB
Needs at 32k3.8 GB65 GB
QuantisationQ4_K_MMXFP4
Parameters4.7B116.8B (5.1B active)
Max context256k128k
API price per 1M$0.06 in / $0.15 outpriced as Granite 4.2 8B$0.03 in / $0.15 out
LicenceApache 2.0Apache 2.0
Machines here that run it37 of 3713 of 37
Cheapest machine that runs itMac mini M6, 16GB $899Strix Halo Framework Desktop, 128GB $3,449

Run Qwen3.5 4B on the Mac mini M6, 16GB · or gpt-oss-120b on the Framework Desktop, 128GB

Jump to: Side by side on the Framework Desktop, 128GB · How much use it takes to pay for the machine · Machines that run one and not the other · The assumptions behind both columns

Side by side on the Framework Desktop, 128GB

The table above gives each model the cheapest machine that runs it, and those are two different machines, so nothing in it is a like-for-like race. The Strix Halo Framework Desktop, 128GB is the cheapest machine here that runs both, so this is the pair doing the same work on the same hardware.

Qwen3.5 4Bgpt-oss-120b
Speed at 32k50 tok/s estimated35 tok/s measured
Pay-back on this machinePays back in 327 yearsPays back in 720 years
API cost per month$1.00priced as Granite 4.2 8B$0.57

Run Qwen3.5 4B on the Framework Desktop, 128GB · or gpt-oss-120b

How much use it takes to pay for the machine

Everything above is at 500k tokens a day. Pay-back moves with how much you actually run, so here are both models at the five levels of use the calculator names, on the Framework Desktop, 128GB. Qwen3.5 4B pays for it sooner at every level of use, so which of them to run does not turn on how hard you work it.

A day's useQwen3.5 4Bgpt-oss-120b
50ka few chats a day3,266 years7,203 years
200klight assistant use816 years1,801 years
1Ma moderate coding-assistant day163 years360 years
4Mheavy coding with an agent41 years90 years
20Magents running most of the day8.2 years18 years

Run Qwen3.5 4B at 20M tokens a day · or gpt-oss-120b

Machines that run one and not the other

Qwen3.5 4B needs 3.8 GB of memory at 32k of context and gpt-oss-120b needs 65 GB. That puts Qwen3.5 4B on 24 of the 37 machines priced here that gpt-oss-120b does not, starting at $899.

MachinePriceMemorySpeed on Qwen3.5 4BPay-back
Mac mini M6, 16GB$89916 GB30 tok/s estimatedPays back in 83 years
Mac mini M6, 24GB$1,09924 GB33 tok/s estimatedPays back in 100 years
Strix Halo Framework Desktop, 32GB$1,26932 GB50 tok/s estimatedPays back in 120 years
Mac mini M6, 32GB$1,29932 GB33 tok/s estimatedPays back in 119 years
MacBook Air M5 (13-inch), 16GB$1,29916 GB30 tok/s estimatedPays back in 120 years
AMD Radeon AI PRO R9700, 32GB$1,299card only32 GB146 tok/s estimatedPays back in 119 years

18 more, on the Qwen3.5 4B page.

Qwen3.5 4B is also head to head with MiniCPM5 2B above it on the leaderboard. gpt-oss-120b is also head to head with Ling 3.0 tiny below it on the leaderboard. One more model needs much the same memory: Llama 4 Scout 17B-16E.

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. Where nobody rents an open model by the token, its API prices are the nearest hosted model's, named beside them. Machines are the 37 here with a published price that are still sold. Change any of it in the calculator.

More head to head: every machine that runs Qwen3.5 4B · every machine that runs gpt-oss-120b · every other match-up · both against the frontier · the quickest pay-back at each level of use