Sharing my similar experience with Skyrim on One X. Immediately after buying my One X, Skyrim ran better than it ever had. I leveled a character to 30 with zero crashes - never in my hundreds and hundreds of hours and dozens of playthroughs had that ever happened. After the patch(es), the initial one to 4K and the subsequent smaller patch, the frame-rate (while tolerable in most areas) has plummeted to unplayable levels in other areas. My main issue, however, is that the loading screens are double or triple what they were - usually taking longer that Oldrim on an XBox 360 - which is abhorrent. Not to mention the fact that Skyrim is causing CTD's that are so severe I'm worried it's going to damage my console. It's causing it to turn itself off and then, when turning it back on, it acts really weird (doesn't respond to being turned on by controller, the load-up sequence takes an extra long time, etc.) and Skyrim is the only game that does this. My mod list is hyper-researched and thoroughly experimented on, I've probably spent more time in the last year doing LO research than actually playing the game, so frankly, with respect to Bethesda, I find it very, very hard to believe it's mod related at this point.