Independent scores put GPT-6 Sol 10 points behind Opus 5.5, and Reddit reports it regressing on GDPval and DeepSWE

r/OpenAI (585 upvotes, 178 comments), Artificial Analysis·high signalXBlueskyLinkedInCopy link

Artificial Analysis scores GPT-6 Sol (max) at 48, rank #18 of 212, against 58 for Opus 5.5. Sol costs $1.06 per index task against about $5.98 for Opus, and it used 77M output tokens on the index where Opus used 260M. A 585-upvote r/OpenAI benchmark roundup says Sol scores about 100 Elo lower on GDPval than the GPT-5.6 Sol it replaces, and says Artificial Analysis traced the drop to deliverables that skipped required parts of the task. Separate threads report Sol doing worse than 5.6 Sol on DeepSWE and Luna 6 as a downgrade from Luna 5.6. For builders, Sol looks like the cheap high-volume tier, not a frontier upgrade.