Short GI

PHY 1 bit HT mixed-format PPDU unverified

A 400 ns guard interval instead of 800 ns.

Reading a capture

Roughly a tenth more throughput for free, at the cost of tolerance for delay spread. Whether it helps is a property of the room, not of the equipment.

Where it sits

HT mixed-format PPDU > HT-SIG > HT-SIG2 > Short GI

Accuracy

Clause
802.11-2024 §19.3.9.4.3
Verified
Not verified against the standard. Treat this as a claim, not a fact.