Stefan, Many people have suffered exactly the same problems as you! If your Cube runs perfectly on the 450mhz upgrade then there is definitely a combination problem with your Cube and the Powerlogix upgrade card. Powerlogix is very aware of this issue and will shortly be releasing a 'fix' that will involve the addition of a custom DC/DC board. If you check out the Cubeowner forums there has been a lot of discussion about your very problem. You will also see more information about the new processor upgrade cards about to be released by Powerlogix and the new service agreement they have with Other World Computing. The best action for you to take is to contact Powerlogix for an RMA number for warranty return and then ship your processor upgrade back to them ASAP. I understand they will be sending out working cards as soon as the new upgrade cards are officially released and all warranty replacements will be served first. Apparently the new upgrade cards are going to be awesome and the custom DC/DC board will ensure that there is plenty of stable power to keep the Cube running happily. Don't waste any more time trying to find the problem yourself - get an RMA number and get your upgrade card back to Powerlogix ASAP. Hope that helps! ... And have a Happy Christmas, Bryce. (still waiting anxiously for my Powerlogix warranty replacement) On 14/12/04 12:19 AM, "Stefan" <no-spam at punkt-x.de> wrote: > Hello friends, > > after a long time of waiting I decided to buy a Powerlogix 100 1.3 > GHz 7457 Upgrade. > > Nervous and with a feeling like christmas I waited and built it into my cube. > In fact: about 3x times faster than my 450 MHz CPU I could measure > with Xbench. Heureka!!! > > But than the problems began: crashes, defect and even dead harddisks > followed and so on. > > Be sure, I did everything like the instructions told me. Three days > and tow defect HDs later I ask myself, what might be the reason. > So I couldn't install more than 10.3: 10.3.2.dmg couldn't be mounted, > same with installation of other software. (I made a clean install, > therefore I can't imagine, that owner rights or preferences can be > the reason...) > > As I remarked, my cube had and has Boot ROM Version 4.1.9 "f". > No, back to 450 MHz, my cube works stable again. > I'm quite sure, the CPU is OK. In fact it > > Has anybody of you had similar problems? > > Very interested > Stefan > _______________________________________________ > Cube mailing list > Cube at listserver.themacintoshguy.com > http://listserver.themacintoshguy.com/mailman/listinfo/cube