Analysis and Conclusions
The charts represent a summary of the FTP-based tests for all products tested in Part 1 of this series as well as in the separate SanDisk WiFi Zire 71 review. Because my test procedures have evolved as I've run into various obstacles along the way, I can't honestly say these results represent apples-to-apples comparisons in all cases.
The main differentiators are that I used different FTP clients - which are noted in parentheses for each result - but I also used a couple of different access points, as well as different files for the transfers. This was not done to give any products an edge over others, but merely a result of the variety of techniques that I had to resort to along the way and the fact that all the testing wasn't done at the same time.
Looking at the FTP results only, one can safely conclude that the palmOne SD WiFi card / PalmOS PDA combinations provide higher wireless speed than the SanDisk SD WiFi card with either the palmOne Zire 71 or any of the PocketPC products tested. From background information and my own speculation, I suspect the biggest factor in the speed difference lies in the SDIO drivers, although SDIO hardware differences can also play a part.
What I don't understand from the FTP data however, is why the PocketPC based devices with internal radios fared so poorly next to the PalmOS-based Tungsten C. Figure 9 shows IxChariot results for the Axim X30 with internal radio, HP 2210 with a D-Link DCF-650W Compact flash 11b card and ASUS A716 with internal radio.
Figure 9: Wireless downlink throughput - Axim X30, HP 2210 w/ CF card, ASUS A716
(click on image for a larger view)
This is somewhat of a mixed comparison, but one key point is that the Axim X30 turned in 5Mbps average throughput - which is right up there with what you'd get from most 11b wireless solutions - with IxChariot vs. only 0.96Mbps using Scotty FTP! There's probably a good explanation for this, but I don't have it. All I can say is that the lower FTP speed was consistent across multiple runs and point to protocol / application overhead as the probable culprit.
Figure 9 also shows that processor speed, or even internal vs. external radio aren't necessarily the deciding factors in choosing a speedy wireless PDA. The A716 and H2210 both use an Intel 400 MHz PXA255, but the H2210 / CF card combo was significantly faster than the A716 with its internal radio (although it did have a lot of throughput "dropouts" which held down the average throughput reported by IxChariot).
So given all the variables, I feel the only fair thing to do is to declare two champions of the crop of wireless PDAs that I tested. The palmOne Tungsten C is still the speed champ in the PalmOs camp and the Dell Axim X30 takes the top slot for the PocketPC-based devices tested.