This is a weird one. at least for me.

I am having trouble with switching my wifi to anything other than B mode.
if i switch to G my ping rockets from 1-10ms to 200ms+ with freezes randomly on the laptop/android/anything.
if i switch to B/G/N same thing
N by itself. same thing.
The only thing that works is B mode only.

This is on two devices first being the RB2011.
and a rb600 with a wifi card AR5213.

I also tried with and without encryption. no difference at all.

By the way I do live in an apartment building with lots of signals around me.

Reset the device to factory setting and just apply basic configuration and try again.

If no changes,

The version may not be compatible with card that is if the card is not MT card. Try swapping the card also and you will find solution.

If same, upgrade or downgrade the OS depending on the version you have running.

Do let us know the resolution.

Thanks for the reply, JP_Wireless

as i said this is also the same exact problem on the rb2011 which has a built in wifi. they are both (the rb600 and the rb2011) using version 6.7....