Gotcha. I am waiting on a huge download to finish and I don't really want to interrupt it, so I will do that as soon as it finishes (it's almost done).
I switched one of the DIMMs to another slot and now it's reading as dual channel. I then went into the bios and set the DRAM frequency to 1066.
These are my new readings:
looks like CPU-Z still reads it as PC2 6400 instead of 8500.