Much as synthetic benchmarks (more on my
benchmarking methods later), particularly video tests, don't necessarily show the real
difference between devices, a new one, which shows the benchmark data of the I-Mate JasJar, the Dell Axim X51v and the HP iPaq 2190, is definitely worth checking out if you really want to get a WM5 device ASAP.
The results can be found here
As can be seen, the x51v, where not directly affected by the graphics speed impact by VGA, is the fastest device.
Addition: What about more real-world tests, you may ask. I prefer tests that come up much more often in real worlds and show the overall speed of the entire architecture. Some of them:
The achievable maximal (download) speed with Wi-Fi
Searching speed in (large) documents
Pocket Internet Explorer rendering speed with enabled cache
(also see the above-linked Searching speed in (large) documents