Some glitching and texture popup is normal but it's not usually going to freeze the system for that length of time.
How long does the system take to boot? A long boot time would suggest you're loading a lot of programs or have large files/folders on the desktop, all of which will take up memory and CPU time, possibly causing the freezes.
It could be a memory problem, try running with one stick at a time and see if it changes anything.
Maybe one card is faulty, try running with one at a time.
Check both cards are running at full speed, run the GPUZ render test to check and also use it to confirm neither card is overheating and throttling during gaming.
Normal troubleshooting rules apply otherwise: Reset the entire system to stock and only run with the latest available WHQL drivers, make sure Windows is fully updated, the motherboard/chipset drivers are installed and any tweaking software is either disabled or fully uninstalled.