AI League — Game Day 15: Grok Posts Back-to-Back Double-Digit Speed Drops as Flash Fights Back

xAI's Grok 4.3 just posted its second straight double-digit speed collapse — 143.5 t/s today, down from roughly 164 t/s on Day 14 and a steep 31% off its season-high of 207.6 t/s set just four days ago on Game Day 11. Two consecutive losses of that magnitude aren't variance; this is a full-blown slump. Meanwhile Google's Gemini 3.5 Flash answered with a partial recovery to 150.9 t/s, Claude Fable 5 sits unfazed at the top of the intelligence board, and off the field a fresh Similarweb report confirmed what the speed numbers have been hinting: Anthropic is eating OpenAI's lunch at the audience level too. 1

The intelligence rankings haven't moved since Claude Fable 5 landed on Day 13. Claude leads alone, GPT-5.5 holds second, and the Google duo holds third and fourth.

Sources: Artificial Analysis Intelligence Index v4.0, measured via each provider's first-party API. 2 3 4 5

Grok entered the week as a speed story. On Game Day 11 it crossed 207.6 t/s, a new season-high and a 43% jump from its May 29 baseline of 145.2 t/s. That was the headline. Then the floor started dropping.

Day over day since the peak: −9.5% on Day 12, −12.5% on Day 13, −13.4% on Day 14, now −12.5% on Day 15. Three of the last four games have seen double-digit declines. Grok still sits above Flash by 7.4 t/s — but at the start of the week that margin was north of 50 t/s.

Flash, for its part, managed a +3.3% recovery from yesterday's reading of roughly 146 t/s. Not a comeback, but it stops the bleeding and keeps Google's speed flagship in the hunt. 6

GPT-5.5 produced 50.1 t/s — barely moved from yesterday's 49.8 t/s. OpenAI's flagship has now spent three consecutive game days hovering in a narrow 49–51 band, which by this season's standards reads as a prolonged plateau rather than a temporary dip. 4

No pricing changes today, but the spread between the top of the intelligence board and DeepSeek remains the most striking table in the league.

The raw number: running the full Artificial Analysis Intelligence Index on Claude Fable 5 cost $9,939.80. The same test on DeepSeek V4 Pro cost $267.82 — 37× cheaper for a model that scores 13 points lower on the intelligence index. 7 That gap has been widening all season, and nothing on today's board changes it.

No new entrants today, but the open-weights standings are worth a frame. Kimi K2.6 and MiMo-V2.5-Pro both sit at 54 on the intelligence index — one point above DeepSeek V4 Pro and one below Grok. The open-source community team keeps pace while carrying a fraction of the compute overhead. 2

Meta's Llama 4 Maverick clocks in at 102 t/s at a $0.34/1M blended rate, but its intelligence score of 18 keeps it off the main board. 8

The speed and intelligence tables tell one story; web traffic tells another. Similarweb's June 2026 update, released June 11, measured the generative AI website traffic landscape as of May 26, 2026: 9

Gen AI website traffic share: Jun 2025 vs. May 2026. Source: Similarweb, published Jun 11, 2026. 9

OpenAI still runs the largest share in the room — 52.7% is not a small number. But its franchise value has been declining at nearly 2 points per month for a year straight. Anthropic's counter-pressing safety squad now holds almost as much share as Grok and DeepSeek combined in the traffic column.

Claude Fable 5: Intelligence throne held. Day 3 of the Fable 5 era with no challengers in sight.

xAI: The speed record from Day 11 looks increasingly like a single hot quarter. Grok has now given back 64.1 t/s — 31% of its season-high — in four days. No injury report from the front office.

Google: Flash stops the bleeding with a 3.3% recovery; Gemini 3.1 Pro holds steady at 111.3 t/s. Still the best value-per-intelligence-point in the top five of the intelligence board.

OpenAI: GPT-5.5 is parked at 50 t/s and has been for three consecutive game days. Season-best was 64.7 t/s on Day 8. The gap between peak and current form stands at 22.6%.

DeepSeek: The low-budget dark horse still offers 52 intelligence points for $0.18/1M. Doesn't sprint, doesn't stutter. Just shows up.

See you on Day 16. #AILeague