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Gemini 4 Argon vs Gemini 3.8 Flash

Reading a 26.2K-token pull request costs $0.0524 on Gemini 4 Argon, 2.7× the $0.0197 it costs on Gemini 3.8 Flash. Both sit in the mid-range price tier, so the choice between them is about review quality more than budget. The benchmark cannot separate their recall: Gemini 4 Argon minus Gemini 3.8 Flash is +14 pts (95% interval +2 pts to +27 pts).

Side by side

Gemini 4 Argon and Gemini 3.8 Flash side by side
FigureGemini 4 ArgonGemini 3.8 Flash
Price tierMid-rangeMid-range
Bugs caughtshare of known bugs82% (better)68%
False alarmsper clean PR1.11.0 (better)
Cost per reviewmeasured$0.0527 (better)$0.0862
Cost per bug caught$0.0706 (better)$0.1166
Exact linecatches on the expected lines78%94% (better)
Review timemean99s (better)427s
Typical review calllist price$0.0766$0.0287 (better)
Input / 1M tokens$2.00$0.75 (better)
Output / 1M tokens$10.00$3.75 (better)
Context window1M1M

Head to head

The known bugs both were scored on, by who caught each in at least one run.

Of 42 known bugs both were scored on: Both 29Only Gemini 4 Argon 7Only Gemini 3.8 Flash 2Neither 4

By language

Share of known bugs each model caught, by language
ModelAllTypeScript6 bugsGo4 bugsJava4 bugsRust4 bugsC#3 bugsJavaScript3 bugsKotlin3 bugsPHP3 bugsPython3 bugsRuby3 bugsSwift3 bugsC++2 bugsC1 bug
Gemini 4 Argon82%83%50%83%75%89%67%100%100%83%100%100%100%0%
Gemini 3.8 Flash68%83%75%43%75%78%67%0%50%83%100%100%50%50%

Where they differ

Of the 42 known bugs both were scored on, both caught 29 and neither caught 4. Gemini 4 Argon caught 7 bugs that Gemini 3.8 Flash missed: 3 in Kotlin, 2 in Java, 1 in C++ and 1 in PHP. Gemini 3.8 Flash caught 2 bugs that Gemini 4 Argon missed: 1 in C and 1 in Go.

On pull requests with no known bug, Gemini 4 Argon raised 1.1 false alarms per review and Gemini 3.8 Flash 1. A measured review cost $0.0527 on Gemini 4 Argon, 39% less than $0.0862 on Gemini 3.8 Flash.

Each known bug, and how often each model caught it
Pull requestLanguage · kindGemini 4 ArgonGemini 3.8 Flash
ggml-org/llama.cpprpc : cache and reuse compute graphsC++ · Security1/10/1
kotest/kotestFix DataClassEq comparatorKotlin · Logic1/10/1
kotest/kotestRefactor eventually to ensure wall-clock time usageKotlin · Error handling1/10/1
ktorio/ktorKTOR-9171 Redesign ByteReadChannel.readUTF8Line APIKotlin · Logic1/10/1
mockito/mockitoAdd core API to enable Kotlin singleton mockingJava · API misuse1/10/1
symfony/symfony[Security] Allow multiple OIDC discovery endpointsPHP · Security1/10/1
jhy/jsoupStore cached child els in Attributes, not fieldJava · Concurrency1/20/4
c-ares/c-aresEvent Thread could stall when not notified of new queries on existing connections that are in a bad stateC · Resource handling0/11/2
golang/gocrypto/tls: add LocalCertificate to ConnectionStateGo · Logic0/12/2

Defects caught over all runs: a PR reviewed three times with one known bug shows 3/3 when it was caught every time.

Every bug each was scored on: Gemini 4 Argon and Gemini 3.8 Flash.