Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Grok 4.20
73
Grok Code Fast 1
40
Pick Grok 4.20 if you want the stronger benchmark profile. Grok Code Fast 1 only becomes the better choice if coding is the priority or you want the cheaper token bill.
Coding
+9.8 difference
Grok 4.20
Grok Code Fast 1
$2 / $6
$0.2 / $1.5
233 t/s
172 t/s
10.33s
2.81s
2M
256K
Pick Grok 4.20 if you want the stronger benchmark profile. Grok Code Fast 1 only becomes the better choice if coding is the priority or you want the cheaper token bill.
Grok 4.20 is clearly ahead on the provisional aggregate, 73 to 40. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Grok 4.20 is also the more expensive model on tokens at $2.00 input / $6.00 output per 1M tokens, versus $0.20 input / $1.50 output per 1M tokens for Grok Code Fast 1. That is roughly 4.0x on output cost alone. Grok 4.20 is the reasoning model in the pair, while Grok Code Fast 1 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Grok 4.20 gives you the larger context window at 2M, compared with 256K for Grok Code Fast 1.
Grok 4.20 is ahead on BenchLM's provisional leaderboard, 73 to 40. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 76.7% and 70.8%.
Grok Code Fast 1 has the edge for coding in this comparison, averaging 70.8 versus 61. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
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