vvoois
(vV)
2
People have reported problems with UAD before. Have you checked the drivers? Using a specific version may help.
http://forum.renoise.com/index.php?/topic/29548-buggy-plug-heavy-cpu-spike-loading-first-uad-1-dsp-plugin/
http://forum.renoise.com/index.php?/topic/17809-buggy-installation-some-uad-1-vst-plugins-crashed-during-scan/
HotelSinus is a UAD1 user, he might be able to help out or perhaps others as well.