EDIT - ussnorway had the answer I needed, Thank you x9000!

I have a Dell xps with 8gb ram, a 480 8gb graphic card.

This doesn't happen all the time, but when I am in a huge boss fight, the screen freezes and I cannot do anything. The music is playing, but everything stops.

Pressing Ctrl Alt Del doesn't do anything and I have to completely sign out and go back in order to get the computer to function normally.

This last time, I was fighting a metal Golem with a bunch of giant bats and Harpies, It took me a bit to realize the parts I needed to hit weren't on the Golem, then Death came in and caused the freeze.

Is there a workaround for this? is this due to a memory leak?

Haven't had anything of the sort happen to me. Only a single crash to desktop in 130 hours of playing, and I've left the game open for very long periods of time.

Maybe a driver issue?

For the record, I have a GeForce GTX 970 and I'm using the 376.53 drivers.

Ok this is definately related to "Death" since I have updated everything I can think of and anytime he appears, and I start fighting him, the screen freezes.

I have not had any issues with my first two playthroughs so I really have no idea why this is happening.

did you try disable the sync and notice overrides until you get past that boss?

I'll give that a try and post back with the results.

I actually hadn't thought of that so, wish me luck!
And thank you so much for your help.

Edit - I was able to get past the Metal Golem but death has not shown up again in order for me to decide if it was the unchecking the Sync or that he just hasn't shown up yet.

Death has 2 guaranteed and one almost certain spawn upon entering certain areas for the first time. If you haven't made it that far yet, that would be your chance to check if Death is causing the issue. Otherwise you may have to use some Rancid Bait Meat and hope that Death is the one to show up.

Ok, finally encountered Death again and no freeze at all.

I disabled Sync and reverified the game, those seemed to do the trick, Many MANY many many thanks to ussnorway for being brillant, thank you soo much!