I had 2 AP800s connected via a wireless bridge,

Therehave been performace issues for some time. Then the Ethernet on one of the AP800s stopped working. I have replaced it with an AP810 and got it working but the connection is still slow

The AP800 is on firmware 1.1.5 The AP810 is on 1.1.6

Even sitting right next to each other I'm only getting about a 10mbps connection. Ping times are 5-25ms too. Pinging over ethernet gets <1 ms

Any advice on getting a more reliable connection

are they both fixed to 802.11 N only? if you allow mixed modes then the speed is likely to differ.
Are they acting as just a bridge or Wifi access points too - this will also slow then down.

I am only really failure with the 900s and 910s but the principle is the same