If you run 64 bits windows (xp or vista), you might want to try this experimental upgrade which makes the server core 64 bits. The server is not faster, but can handle bigger DICOM objects, although the size limit is not yet known. For the 32 bits version it is around 500 MB. For this version it may be 2 GB or more.
Download it here:
Please read the enclosed readme.txt. I believe it works with all databases, but mysql requires some tweaking. The version is set to 1.4.14a, and it fixes some issues raised on 1.4.14.