ABC (and torrent stuff in general) is a pretty big resource hog, especially when it first starts up. It's going to depend on how many files your DLing at once and how big they are, more than anything else. When you start or resume a file, it has to check what you already have of it, which is the worst time for your system resources, especially if the file is large. Once that's done, it's mostly a matter of how many files you have DLing. While I can usually handle upwards of 10 in most P2P programs, I had to cut it down to 3 with ABC, and then things ran mostly ok. I still had considerable slowdown starting up new applications, and transfer rates from websites were really slow even when ABC wasn't really moving a lot, but I could manage. This was on a 2.8GHz P4 w/512MB Ram. Hope that means something to ya. I'm hving 8 items in ABC now with 6 active and my comp work fine... But yeah, the hash check is a bit of a pain, but I'm glad you don't have to wait for that when you're seeding.