Google Gemini 4 Carbon Is Out! World #1, but It Performs Like Argon?

3-Line TL;DR

Google announced Gemini 4 Carbon on October 28, and it took first place on the Artificial Analysis Intelligence Index with 59 points, nine above Gemini 4 Argon, at the same price and almost the same cost per task
On other scoreboards the gap nearly disappears: Vals AI has Carbon at 70.4% vs Argon's 69.2%, and Arena's text board puts them 8 points apart with overlapping error bars
Carbon is only open to selected cyber defenders for now, with no date for the Gemini app or Antigravity, and Argon on the $19.99 Pro plan already runs out fast

Google released Carbon on October 28, two weeks after Argon (Google)
It scored 59 on the Artificial Analysis (AA) Intelligence Index v5, ahead of Claude Opus 5.5 (58) and GPT-6 Astra (57) (Artificial Analysis)
On the same board Argon sits at 50, eight points behind Opus; two weeks after Argon, Google is on top, so it was clearly sharpening its knife
In Google's own comparison table, Carbon has the best score in 15 of 17 rows, losing only FrontierSWE 2 to Astra and OSWorld-2.1 to Opus 5.5

Google's benchmark table for Gemini 4 Carbon, top rows: AA Index v5.0 Carbon 59 vs Argon 50, Vals Index v2.2 Carbon 70.4% vs Argon 69.2%

Source: Google — Gemini 4 Carbon evaluation table, top rows; red box added by HSL

The API price is the same as Argon's: $2 input and $10 output per 1M tokens during the launch period, then $4 and $20
AA charges the full price and puts Carbon at $7.76 per index task, against Argon's $7.68
Paying 8 cents more per task for nine more points is about as good a deal as a model upgrade gets

The nine-point gap is AA's number; two other public boards see a much closer race
Vals AI's index, a mix of finance, legal and coding tasks, has Carbon at 70.36% and Argon at 69.24%, about one point apart
On Arena's text board, where people vote between two anonymous answers, Carbon (1528 ±9) edges out Argon (1520 ±6), but the error bars overlap and Carbon's score is still marked preliminary
Google's own table tells the same story: Carbon is ahead everywhere, but the size of the lead swings a lot

Dumbbell chart of Argon vs Carbon scores on 12 benchmarks from Google's table, sorted by gap from +0.9 on Chartography to +12.8 on ExploitGym

Made by HSL — numbers from Google's Carbon evaluation table; the AA Index row is in points, the others in percent

Chartography (reading charts), the Vals index, AutomationBench and CWE-bench move by three points or less
The big jumps are hacking-related work (ExploitGym +12.8), reading very long documents (GraphWalks +12.0) and science tasks in a terminal (+11.9)
That fits Google's pitch: Carbon is built for cybersecurity and long, multi-step work
So the headline depends on the job: for everyday chat it may feel like Argon; for long agent runs it looks like a real step up
One trade-off: on AA's knowledge quiz Carbon answered more questions correctly than Argon (58% vs 48%) but also guessed wrong more often instead of saying "I don't know" (11% vs 4% hallucination rate)
Google says its internal tests show half as many unsupported claims as Argon, but that is a different test with a different definition

Scatter chart of AA Index v5 score vs cost per task: Carbon 59 at $7.76, Argon 50 at $7.68, Opus 5.5 58 at $10.04, Astra 57 at $6.25, Sol 55 at $1.27

Made by HSL — Artificial Analysis cost per index task at standard prices; Sol from the v5 announcement; Opus, Astra and Sol at max effort

Cost per task is the full bill for one test item, including reasoning tokens, not the token price
GPT-6.1 Sol is still the cheap option: 55 points for $1.27, about a sixth of Carbon's cost

Google is giving Carbon first to a subset of cyber defenders, then to trusted partners in its Fairwind Program
Developers, businesses and consumers get it "as soon as possible", with no date
On October 29 the Antigravity model list still shows Argon at the top, and Carbon is not there (Antigravity docs)
Argon went the same way: announced on September 30 for defenders only, opened up on October 13

Timeline: Argon announced Sep 30 and released Oct 13; Carbon announced Oct 28, with Fairwind partners and everyone still undated

Made by HSL — dates from Google's Argon and Carbon posts

If Google repeats Argon's pace, Carbon would open around November 10, but that is my guess, not Google's plan
Argon's launch discount ends on November 30; AA says Carbon's discount has no confirmed end date

In my Argon post each question on my AI Pro plan took about 5% of the usage meter, and it still feels stingy
Google counts subscriber usage by compute, so harder prompts, higher thinking levels and longer chats use up more (Gemini Help)
Pro limits refill every five hours, with a weekly cap on top
AA's full index run used about 200 million output tokens on Carbon versus about 110 million on Argon (AA Carbon, AA Argon)
If the Pro meter tracks work like that, the same meter could drain faster on Carbon; Google has not said anything about Carbon's limits yet

A user holds a Pro plan card with an almost empty usage bar while a #1 model robot holds a trophy at the counter

Champion at the counter, two questions on the card

One good change: Antigravity, Google's coding agent app, now lists Argon for paid AI Pro plans; on October 14 it was Ultra only
The app itself has been fragile; four days of release notes include these fixes (changelog):
- Oct 22: agents stopping after sleep or a Wi-Fi change instead of reconnecting, and a failed undo wiping the conversation
- Oct 26: a broken saved session blocking sign-in
- Oct 27: conversations switching to a different model after a restart
The Gemini app had its own bad day on October 8, with error messages and about 4,800 Downdetector reports at the peak (Tom's Guide)
So my request to Carbon, the new top student: please fix the Antigravity software and the chat app first

What you want	What works now
Try Carbon in chat or Antigravity	Wait; no date yet
Google's best model today	Argon on AI Pro ($19.99) in the Gemini app and Antigravity
Carbon through the API	Only for selected partners for now
Cheap and close to the top	GPT-6.1 Sol: 55 points at $1.27 per AA task

Hacker News user nater5000 says Carbon could justify a subscription if it delivers the improvement at Argon's price (no measurements) (Hacker News)
Another HN user, thefourthchime, calls it "another Gemini release where they don't release it" (Hacker News)
A new Pro subscriber on r/Bard, Xhite, likes Argon's answers but hit a wait of a couple of hours after five messages (Reddit)
On r/google_antigravity, touhami_dz reports Antigravity 2.22.0 on Windows 10 losing its login on every reboot (Reddit)

Q. Is Carbon a new model or an Argon update?
- Google calls it its strongest model and says it uses the same safety stack as Argon, but does not say how it was trained
Q. Argon scored 53 in your October post. Why 50 now?
- AA changed its test mix with v5 on October 27, so all scores moved; compare models only within the same version
Q. Will Carbon come to the AI Pro plan?
- Google has not said; Argon reached Pro in the Gemini app on launch day and in Antigravity later
Q. Should I wait for Carbon or use Argon now?
- For chat, Argon is close on Vals and Arena, so I would use it now; for long agent or security work, Carbon looks worth waiting for