Grok 4.5 is Opus-class at 40% of the price, and the independent evals mostly agree

SpaceXAI released Grok 4.5 on July 8, and for once the vendor hype and the third-party numbers point roughly the same direction. Musk called it "roughly comparable to Opus 4.7, but much faster." Priced at $2 per million input tokens and $6 per million output, that's over 60% below Opus 4.8 and GPT-5.5.

Normally I'd roll my eyes at a founder calling his own model Opus-class. What makes this one worth your attention is that independent evals back a mixed-but-strong read instead of a marketing read. Artificial Analysis scored it 54 on its Intelligence Index, fourth overall behind Fable 5, GPT-5.5, and Opus 4.8, and a full 16 points above Grok 4.3. Snorkel's GDPVal+ was more striking: a 29% mean pass rate, beating GPT-5.5 at 22% and Opus 4.8 at 21%. The benchmark picture is genuinely split, which is the honest part. It leads Opus 4.8 on DeepSWE 1.0 and Terminal Bench 2.1 but trails on the neutral DeepSWE 1.1 and SWE-Bench Pro. It was trained alongside Cursor, so expect it to look especially good inside that editor.

The reason this is the most builder-actionable release in a crowded week is the shape of the tradeoff. For years, price tracked capability almost linearly. You paid frontier prices for frontier results. Grok 4.5 breaks that assumption with numbers, not vibes. Fourth-best on a neutral index at less than half the cost is a real decision, not a talking point.

Pair it with Cognition's SWE-1.7, which shipped the same day. It hits 42.3% on FrontierCode 1.1, close to GPT-5.5's 43.0% and behind Opus 4.8's 46.5%, running at roughly 1000 tokens per second via Cerebras for about $1.97 per task. Two near-frontier coding options landed in one day, both priced around $2. The catch on SWE-1.7 is that it's Devin-only with no direct API, so it's not a drop-in.

What I'd do: if you're running a fan-out harness that makes lots of cheap subagent calls, this is exactly the workload where a 60% price cut compounds. Route the high-volume, lower-stakes calls to Grok 4.5 and keep Opus for the verification pass where the extra 5 benchmark points actually decide correctness. The frontier isn't one model anymore. It's a routing decision, and the cheap tier just got good enough to matter.