Thanks to all for the feed back and links to info confirming the problem. I have to say, except for the first couple of times we experienced this issue (the hoops we had to go through to get them to agree to send a repalcement MB), Dell hasn't questioned the MB replacement requests. Now I have to see, given the machines are out of warranty, what their stance will be. Unlike our Dell servers, we never received any notification about this defect. If so we would have requested preemptive replacements here as well. Most likely anyone receiving such notice would have done as much. What a support nightmare that would have been for Dell, HP, or any other manufacturer subject to the problem. Normally we are on a 3 year replacement cycle (in line with the warranty expirations) for our PC's. However this cycle we want to wait until the Optiplex's start shipping with Vista (or a free upgrade is offered). We don't plan to migrate to it right away. But paying separately for an OS upgrade 9-12 months into our life cycle for 90+ machines isn't cost effective. Again, thanks for the feedback. Hopefully Dell with offer up some type of extension given it's a know problem. At least I have some good info to plead the case. - Al