Hi, thanks for the response, some notes. I know that the dll's won't be reused, that's why I want to UPX only the rarely used ones, which I think there are a lot...problem is more which one is rarely used and which one much. Mhh I think it's more an idea then realistic to do it. I have disabled the pagefile and hiber file. The clustersize is probably a good one, because there is now 16MB wasted.