Muse Wonder vs Grok 4.5: The Model That Is Two Generations Behind Costs a Fifth as Much per Task

Muse Wonder and Grok 4.5 are not really rivals; they are an argument. Meta released Muse Wonder on 12 October 2026, x​AI released Grok 4.5 on 8 July 2026, and x​AI has since shipped Grok 4.6 and Grok 4.7 on the same rate card. So the older model is not current even by its own vendor's reckoning, which makes its numbers useful in a way a fresh competitor's are not: Grok 4.5 is the price floor for a competent reasoning model, and Muse Wonder is what the top of the board costs. Artificial Analysis puts the difference in one line — about $4.52 per completed Intelligence Index task for Muse Wonder against about $0.88 for Grok 4.5, with thirteen index points between them. Whether thirteen points is worth five times the bill is answerable only if you know what your tasks actually cost, which is the part the rate card never tells you. Pricing and index changes that land after a comparison like this one are logged with their dates and sources in the AI Incident Archive, next to the other model and vendor incidents we track.

Thirty-nine versus fifty-two on the same board

Both figures come from the same harness, version 4.3.2 of the Artificial Analysis Intelligence Index, which bundles ten evaluations — Terminal-Bench 4.0, SciCode, Humanity's Last Exam, GDPval-AA, AutomationBench-AA and five others. Grok 4.5 scores 39, which lands it 63rd of 213 and, in the evaluator's own words, above average among comparable models whose median is 27. Muse Wonder scores 52 and sits 9th. The evaluator's one-line summaries are worth quoting next to each other because they describe the trade in plain language: Grok 4.5 is "above average and slower than average"; Muse Wonder is "leading intelligence, somewhat expensive for its price tier, notably fast, and somewhat verbose".

The interesting column is not the score, it is what each model emitted to earn it. Grok 4.5 produced 77 million output tokens on the index run — close to the board median. Muse Wonder produced 130 million, and the board median has risen to 85 million since. Meta's model is verbose; x​AI's is not. That one fact does most of the work on the cost side, and it works against the model with the richer rate card, which is the counter-intuitive direction.

How the rate card becomes a five-times bill

On paper the gap is 2× input and 3.3× output. Measured, it is 5.1× per completed task, which means verbosity is amplifying the price gap rather than cancelling it — the opposite of what happens when a cheap model is the chatty one.

• List price — Muse Wonder $4.00 in / $20.00 out / $0.20 cached per million; Grok 4.5 $2.00 in / $6.00 out / $0.30 cached

• Cost per index task — Muse Wonder about $4.52; Grok 4.5 about $0.88

• Output tokens on the index run — Muse Wonder about 130 million; Grok 4.5 about 77 million

• Time to first token — Muse Wonder 30.35 seconds; Grok 4.5 8.90 seconds

• Output speed — Muse Wonder 145.1 tokens per second; Grok 4.5 59.1

• Context window — Muse Wonder 1,048,576 tokens; Grok 4.5 500,000 tokens, with the whole request repricing above 200,000

That last row is the one place Grok 4.5's cheapness stops being cheap. x​AI tiers the rate card by prompt length: under 200,000 tokens you pay $2.00 and $6.00; above it, the entire request moves to $4.00 and $12.00, and the cached rate doubles from $0.30 to $0.60. Muse Wonder charges one rate across its full million-token window. At 300,000 tokens of prompt, Grok 4.5's input price has doubled while Muse Wonder's has not moved — the 2× headline becomes 1× on input, and the cost-per-task gap narrows to whatever the output volume does to it.

Speed inverts the usual advice

Grok models are usually the fast option and this comparison is the exception. Grok 4.5 waits 8.9 seconds for its first token and writes at 59.1 tokens per second; Muse Wonder waits 30.35 seconds and writes at 145.1. Neither is a fast interactive assistant. But the shape is different in a way that matters for agent loops: Muse Wonder deliberates once and then moves quickly, Grok 4.5 starts sooner and then crawls. Over a long generation the two converge; over many short turns, Grok 4.5's lower first-token latency wins, and over a single large output, Muse Wonder does.

This is also the argument against treating Grok 4.5 as the budget choice for production. A model that is cheap per token but slow per token can lose to a model that is expensive per token but fast, once you price the wall clock — and in an agent that makes repeated calls, the wall clock is usually the thing the user notices first.

The successor problem

Everything above compares Muse Wonder to a model x​AI has already replaced twice. Grok 4.6 arrived with the same rate card and a better score; Grok 4.7 has since landed at 46 on the same index, and Artificial Analysis explicitly flags Grok 4.5 as deprecated and points to 4.6. So the honest version of this matchup is not "Muse Wonder versus Grok 4.5" — it is "Muse Wonder versus the Grok you would actually deploy", and that comparison is much closer on capability: 52 against 46, roughly six points rather than thirteen, for about $4.52 per task against Grok 4.7's $3.74.

We are publishing the Grok 4.5 comparison anyway because that is the model a lot of readers are still routed to, and because the older model makes the economic structure visible in a way the newer one blurs. But no one should choose Grok 4.5 today on the strength of this page. If the answer is "a Grok", the answer is 4.6 or 4.7.

Where the two are reachable

Both Grok 4.5 and Grok 4.7 are in the OrcaRouter catalogue — grok/grok-4.5 at $2.00 input, $0.30 cached and $6.00 output per million tokens up to 200,000 tokens, repricing to $4.00, $0.60 and $12.00 above it, with the 500,000-token window intact; grok/grok-4.7 at the same rates with a $0.50 cached read. Those are x​AI's list prices passed through with no markup, so when x​AI changes a tier the change is live on our side the same day. Muse Wonder is not in the catalogue: there is no meta/muse-wonder on OrcaRouter, and the Meta checkpoints we do carry are meta/muse-spark-1.2 and meta/muse-spark-1.1 at $1.25 and $4.25 per million tokens.

The routing point that earns its place here is the failover one. Muse Wonder is ten days old with a 30-second first token and a single independent evaluation; putting a production path behind it on faith is the wrong risk to take. Point a share of traffic at it beside the Grok you already run, keep the rest where it is, and let automatic failover absorb the timeouts while you learn whether the long-horizon strength Meta claims shows up in your workload. One key reaches the Grok side of the comparison today; the Muse Wonder side is a second API call away, and the switching cost is a model string.

The pick, in one paragraph each

Choose Muse Wonder when the task is long, the answer is worth getting right, and the prompt is large enough that Grok's 200,000-token repricing would erase its price advantage anyway: the flat million-token rate, the 145 tokens per second and the thirteen-point index gap all point the same way. Choose a Grok — and specifically Grok 4.7, not 4.5 — when you need many short calls, a first token in single-digit seconds, and a bill that survives volume, because at $3.74 per completed task against $4.52 it is the cheaper way to be roughly as capable. What you should not do is pick Grok 4.5 because it appears at the top of a comparison table; its own vendor has stopped recommending it.