Hi -
some EEE PC models use a Atheros mPCI wireless card (the 701 for example) but my 901 was shipped with a Ralink rt2870 (802.11 abgn) that I replaced with an Atheros abg card ASAP...
Actually I'm using Ahdemo mode in my EEE-PC which works nicely together with other devices with 'normal' IBSS-mode but fixed IBSS-ID - in our local mesh we use Madwifi with OpenWRT patches and Broadcom-based devices (WRT54G/GL/GS, Asus WL500GP) with OpenWRT Whiterussian and Broadcom proprietary driver with fixed IBSS-ID hack (Freifunk Firmware).
Rate adaption with the Ministrel algorithm works well in Ahdemo mode - and you have the possibility to set up a AP VAP on the same interface, too.
Performance is fine. That may be different if you run a Ahdemo-only network in range with other wireless networks - they won't detect collisions, hence performance can suffer.
Cheers, elektra