The processor shows almost no load during this time. Even compiling and starting from an external browser does not help.
Strange is that we do have two other computers (one Windows XP one Linux) with exact the same setup where the hosted mode is working at normal speed without any problems for the same application.
Do yourself a favour, move to GWT 2.0 (currently in RC2) and take advantage of Out Of Process Hosted Mode (OOPHM), which lets you debug straight in the browser, and is lightning fast!
Try removing all breakpoints. It helped me in such a scenario. Apparently if you place breakpoints in critical points in the program, it can cause everything to grind to nearly a halt in hosted mode.
I second the suggestion to switch to GWT 2. Please note, however, that with GWT 2, hosted mode is very slow in Chrome. I recently switched from 1.7 to 2.0 and found hosted mode to be very slow ... until I switched to Firefox. Reason for this is that Chrome's process model is not benificial to OOPHM, at least now.
A few ideas:
<li>Does the slow Windows box have a heavily fragmented hard-drive?</li>
<li>Is it a specific database query that's taking a long time once the application is running, or are all interactions slow?</li>
<li>Are the project files on a local filesystem?</li>
<li>Is the database on a local filesystem?
<li>If so, does it have the same size data set as the other machines?</li>
<li>If not, are they on different subnets or have different bandwidth available?</li>