Hi, Mike lean me on to post some of my personal benchmarks. In one project I generate pretty large set of HTML pages (more then 5000, total size 40 MB) from single 16 MB XML file. During processing a lot of key lookups and calculation is done (you can see output at http://studijniplany.amu.cz). Saxon finishes this stylesheet in less then 3 minutes and consumes ~130 MB of RAM. For the most of the time Saxon utilizes only 70% of CPU -- disc is probably slower then Saxon ;-) I tried the same stylesheet and data with Altova2007. After 30 minutes only 400 files from 5000 vere generated and 950 MB of RAM was vasted, CPU utilization for Altova process was over 90%. I decided to interrupt test here. For this stylesheet Altova was at least 100 times slower then Saxon. Moreover Altova eat more and more memory with each outputed file, so there is probably some memory leak in this product. OTOH, Saxon memory consuption was constant after initial loading and preparation of documents.