Don't know about PCI but could get cardbus adaptor for d-link DWA-652
that works well for me or look up it's chip. What usb are you using as
the ones i tried a while back weren't much good though there have been
changes to the drivers since so probably worth trying again.
http://www.ebay.co.uk/itm/D-Link-DWA-652-Xtreme-N-Wireless-Notebook-Adapter-Draft-/400461073245?hash=item5d3d570b5d:g:HdsAAOxyrP9RZur0
For USB I am using the run(4) driver for Ralink 802.11n product
Netsys980000N but my head hurts a bit while using it. Not so good for
long-term use. :-) Works extremely well though, very long-range. But
still, looking for PCI/PCIe.
http://www.dx.com/p/netsys-980000n-2-4ghz-4200mw-high-power-802-11b-g-n-150mbps-usb-wi-fi-wireless-network-adapter-93722#.Vled1noy30M
