Does OS Matter?
Since Win98SE and WinXP are very different operating systems and are based on different TCP/IP stacks, we checked to see what changing the OS would do. Plot 4 shows the results from running the pair of send and receive tests using the Compaq laptop, using WinXP Home then Win98SE. You can see a 10% gain in send performance with XP, but receive performance is about the same in both OSes, including the higher variation in results.
Plot 4: WinXP vs Win98SE
Since the Dell has a built-in Ethernet adapter (a 3Com 3C920 Integrated Fast Ethernet Controller - 3C905C-TX Compatible), we took the opportunity to compare its performance with that of the Linksys PCM200. Plots 5 and 6 show very little difference between the two adapters. Although it would be foolish to say that this means that there are no differences to be found among different CardBus Ethernet controllers in general, we think it's safe to say that you should only consider CardBus adapters for your laptop (if it doesn't already have one built in) if you plan on running on a 100BaseT network.