icloud backup of iphoto is stuck

I just signed up for more storage on icloud to store my 25,000 photo iphoto library in icloud. I have been patiently waiting for this to complete for over a month. In the mean time, it brings our internet speed to a crawl, and has only uploaded about 4,000 photos. I have stopped/restarted, I have unplugged my router, I have rebooted, I have downloaded the latest OSX. My next step is to revert back to google drive, which did not have the same issues. Please help.