Right, no idea how Windows drivers behave. But odds are that the
bottleneck is at the client, since that often has worse antennas than
the AP. If you're in a position to take packet captures at both clients
and AP you may be able to figure it out; may require tightly
synchronised clocks to do properly, though.
I could try running wireshark on both, it's a ton of packets, and I'll be honest, I don't know that *I* would know what to do with them.
How do you see the latency spikes? An end-to-end ping? You could try
pinging the AP from both clients and see which one sees the latency
spike...
steam homestreaming has an in game performance monitor, it shows you your ping, estimated bandwidth, and how fast it's currently streaming. So when the game stutters I also notice a recorded ping/latency increase. Sadly though, it doesn't include highly detailed logs to my knowledge.
Yeah, those are link-layer retransmissions. The ath9k driver sometimes
retries individual packets up to 30 times, which is obviously way too
much...
that's fun...