Try deleting the temp files. I am refering to: "My documents"> DAZ>Carrara8>temp. C8 is much better than C6 or C7 about deleting them, but after any crash, one gets left behind. My C8 speed increased noticeably after deleting a few that I had accumulated.
Also, the first C8 start after a reboot is slooooow, but all subsequent starts are much faster. (Similar to Poser in this respect). I suspect it has to do with checking all the browser links, though this is not confirmed. I usually start C8, then walk away and make breakfast. :)