Claude 3.5 Sonnet vs Step 3.7 Flash

Pick Step 3.7 Flash if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.

Step 3.7 Flash is clearly ahead on the provisional aggregate, 72 to 40. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Step 3.7 Flash's sharpest advantage is in coding, where it averages 56.3 against 49.

Claude 3.5 Sonnet is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.20 input / $1.15 output per 1M tokens for Step 3.7 Flash. That is roughly 13.0x on output cost alone. Step 3.7 Flash is the reasoning model in the pair, while Claude 3.5 Sonnet 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. Step 3.7 Flash gives you the larger context window at 256K, compared with 200K for Claude 3.5 Sonnet.