I think there is thread here about 'overclocked' wi-fi driver by Serge and you can find his reports also in maemo-developers and cx3110x-devel at garage.maemo.org
(thread WLAN Horrible Roaming Performance (N800, OS2008), Software or Hardware Problem ?) Not sure now but the speed was over 1MB/s then. This is partly due to suboptimal code in cx3110x driver and slow SPI bus used for talking to the chip (raising SPI bus clock helps).