Twhat is the most mbs wifi card usb adapter?

Question

like 50mbs, 108mbs, 300mbs.

Answer 1

If you mean the speed, 802.11n (108Mbps) is the fastest...but you may be wasting money if you don't use it to it's full potential.

If you only care about internet, 802.11b (11Mbps) is plenty fast. They don't really sell these anymore but what they do sell is 802.11g (54Mbps) which replaces and is backwards compatible with 802.11b.  This is also what most built-in WiFi laptops and handhelds sold today use. I wouldn't get anything else because it's just a waste of money. Residential broadband internet is usually only 1-5Mbps so even WiFi-b is plenty fast.

If you plan to do file-sharing, you care about the wireless speed more so go with 802.11g (54Mbps) or the new 802.11n (108Mbps).  I should say I've never actually seen 802.11n in action but from what I understand it's compatible with all 4 standards (a/b/g/n) and claims to be wider-range.