I'm running two radeon 5830's however I have found no way to successfully
modify voltage, clock or memory on both cards, just the first one...this
is an extreme disadvantage since in MSI afterburner at least I can do both
cards, but if I want to slightly modify voltage on both I have no way of
doing so. Is there anything I can do to change both cards voltage and
clocks using Trixx? This would help me a lot as I am able to overclock
this card highly, I just need to be able to do it on both of them instead
of just the first.

I went out and bought a crossfire connector but it still doesn't work on
both cards even with crossfire enabled.

We have launched the latest TriXX V4.0.2 that can solve below issue.

http://www.sapphireselectclub.com/ssc/TriXX/TriXX.aspx

Thanks.