I haven't found a single place to find all the issues that bad risers can cause. I'm pretty new to mining and so far have found a number of them.

Here are the issues that I've run into so far:
-GPU not even being recognized (Initially I thought this was motherboard BIOS problem)
-GPU going to code 43 often
-GPU causing more than normal black screen flashes

And the most annoying so far:
-GPU to cause errors in HWinfo

I kept underclocking and adding voltage, but the errors would just continue. At first, I didn't think this could be a riser related issue, but after I changed out the riser, the GPU errors went away and I was able to clock it back up to where I thought it would be. One week of frustration; SOLVED.

Anyone else see any other issues with their risers?

Edit: Forgot to add one. Problems with reported hash rate vs effective hash rate in pool mining.

Moral of the story is, test your risers!