Codex Declines: SemiAnalysis Reveals Claude Opus 5.5 Delivers 5x Value Over OpenAI

Introduction

The author, a veteran AI programming commentator, argues that OpenAI is attempting to distract from its models' inferiority to Anthropic's offerings — specifically slower speed and higher token consumption. The catalyst is a 28-day continuous improvement challenge by Tibo, who announced a 50% default inference speed boost for GPT-6 Astra and GPT-6.1 Sol across all ecosystem partners including Devin, OpenCode, Amp, and Pi.

Hours before Tibo's announcement, SemiAnalysis published a deep-dive report titled "Anthropic Subscriptions Offer 5x+ More Value Than OpenAI," revealing that in real-world workloads, Claude subscription plans deliver equivalent API value more than five times that of OpenAI.

Why Developer Flow Matters More Than Peak IQ

In actual AI programming, the most valuable metric is not a model's single-turn intelligence peak but the developer's Flow . When refactoring a module in Cursor, OpenCode, or a terminal, a developer's mental model runs at high speed; if the model stalls — emitting only a couple of variable names every few seconds — focus is instantly shattered.

Benchmark Comparison: GPT-6.1 Sol vs Gemini 3.8 Flash vs Claude Opus 5.5

A community test compared three models on the same coding task, measuring total elapsed time and effective token-per-second (TPS) output:

Claude Opus 5.5 : 88.12 seconds total, 71.5 TPS

Gemini 3.8 Flash : 185.34 seconds total, 239.1 TPS

GPT-6.1 Sol : 317.95+ seconds total, 20.1 TPS

Many observers wondered why Gemini 3.8 Flash, with over 3x the TPS of Opus 5.5, took nearly twice as long. The answer lies in agent task planning and thought density . Gemini 3.8 Flash outputs explosively like a machine gun, generating extremely long reasoning chains that pile up total tokens; Opus 5.5, by contrast, uses razor-sharp architectural judgment to cut straight to the point, completing the loop with concise, high-signal code. Thus, despite a lower raw TPS, Opus finishes in 88 seconds.

GPT-6.1 Sol is the clear laggard. At 20.1 TPS, a typical Python script requiring hundreds to thousands of tokens forces the developer to stare at the cursor for minutes per confirmation — enough time to forget the calling conventions of the previous function layer.

"Sol's IQ handles daily coding fine, and token consumption is only one-fifth of Astra's, but it's slow enough to make you want to throw your keyboard! My train of thought stays highly coherent, yet by the time it finishes spitting out a code block, I've completely forgotten the parameter rules of the upper-layer function."

Workarounds and Quota Strangulation

Driven to desperation, engineers devised a "poor man's three-layer agent architecture" to mitigate Sol's slowness.

Why not just use Astra? Because Astra burns through quota like dry kindling — OpenAI's weekly quota is exhausted in two days if Astra is used heavily. Under this pressure, droves of developers originally anchored in Codex have migrated en masse to the Claude Opus 5.5 camp.

Subscription Economics: The SemiAnalysis Report

SemiAnalysis's token-economics financial model shows that while subscription revenue accounts for only ~10% of Anthropic's total revenue, subscription users consume over 40% of total inference compute due to high-frequency calls, long-context caching, and endless agent loops. This extreme imbalance drags down data-center revenue per megawatt by a full $36 million.

Faced with this compute hemorrhage, OpenAI and Anthropic diverged onto two opposite survival paths.

OpenAI's "Nuclear Hard Landing": Quota Halved and $500 Upsell

OpenAI's response is ruthless: launch a new $500/month tier offering a 300 TPS "Ultrafast" lane, while simultaneously slashing the quota of the beloved $200/month plan by 50%.

The conspiracy-theory take: OpenAI deliberately throttles default Sol to 20 TPS, cuts quota in half, then repackages the high-speed lane as a $500/month luxury add-on.

Two Divergent Rescue Strategies and the 5x Value Gap

The contrast is stark:

OpenAI chose a blunt nuclear option : slash subscription quota to the bone, retracting losses across the board.

Anthropic chose fine-grained gradient subsidy : fiercely protect the flagship Fable 5.1 model, but on the critical programming productivity tool Opus 5.5 , continue astonishingly generous subsidies.

The normalized comparison chart tells the story: in per-dollar equivalent API value, Claude Opus 5.5 achieves 4 to 5 times the comprehensive return of OpenAI .

Independent developers once praised OpenAI's generous quotas, even forcing Anthropic to roll back reduction plans multiple times. Today, the tide has turned: OpenAI's value-for-money myth in developers' minds has completely collapsed.

"Going from 20 TPS to 30 TPS is like swapping a bicycle for an e-bike, but next door Claude Opus 5.5 is a born Porsche; moreover, their single $200 plan equals five of yours, and you still cut quota in half — this arithmetic is elementary-school level."

Conclusion and Personal Recommendation

If Codex relies on reset gimmicks to maintain reputation while its model capability remains suppressed by Anthropic — not to mention Google's catching up — it will only get "more and more lame."

Based on current experience, the author finds Gemini 3.8 Flash both fast and capable, occasionally supplemented by Opus 5.5 , making it an excellent combination.