In our earlier tests on the S520 and S750, there were sometimes quite lengthy pauses in printing at mid-page which could halve the speed otherwise expected. This was also true of the i520, but we discovered the reason for it. The printers were deliberately bridled to prevent the ink from flowing from one page to the next. The function could be deactivated via the driver in Windows 98 and earlier. In Windows XP, you have to go to Settings/ Printers. In the device properties, click on the Maintenance tab, then Custom Settings, and uncheck "Set printer to ECP mode." The printer will then run at top speed. This is how we tested the i550 and found that, set like this, it runs at twice the average speed. 10 x 15 centimeter prints are turned out in just one minute, and A4 enlargements in a little under three minutes.
In the end, the i550 outpaces the S520. It is, in fact, as good as its big sister, the S750, which has suddenly lost its advantage.