The number one "fix" on this forum for Skyrim is to disable vSync through the "iPresentInterval = 0" tweak in the INI file. However over the last week or so it's come to many people's attention that disabling vSync this way causes all manner of bugs and glitches.

Notice that even if you force vSync through your GPU's control panel, Radeon Pro, DXD3Overrider etc, these bugs will still persist. The only way to stop them, unless noted otherwise, is to set iPresentInterval to 1.

Crazy Physics
Allowing your FPS to go over 60fps causes the physics engine to go a bit out of control. The slightest touch, even opening a door, can send pots and pans 10 foot away flying all over the place. Whilst this may seem funny, it can have disastrous consequences if a really important item flies so fast it gltches out of the playable area.

This can however be solved by limiting your FPS to 60.

Day and time out of sync
With iPresentInterval disabled, the time and day will gradually go out of sync. Shadows update correctly, shops close and open at the right time and the sun sets and rises correctly. However the physical day (for example Turdas) won't change until 5pm. This not only breaks immersion, but can also break some quests where the AI relies on the actual day changing.

NOTE: It has been confirmed that this will cause NPC schedules to go out of sync, and does break some quests.

This cannot be fixed with a FPS clamp, or by forcing vSync externally.

http://www.gamesas.com/index.php?/topic/1280991-do-not-disable-vsync/page__view__findpost__p__19368231

Flickering Water
Only happens on certain systems, however it happens to me. Water LOD is fine, however once you approach the water it constantly flickers when you move the camera.

This can be fixed by forcing vSync externally.

Y Axis Camera Issues
The Y axis of the camera seems to be tied to your FPS when iPresentInterval is disabled. This causes your X axis to function correctly, however your Y axis will alternate terribly over-sensitive and sluggish.

This can be lessened through some INI tweaking and a FPS clamp, however won't really go away completely.

Additional timing issues
Having iPresentInterval set to 0 seems to give some (after an extensive playthrough) delay with certain functions. Namely receiving items off NPCs and getting markers added to the map. These things happen 5-10 seconds after they should.

This cannot be fixed with a FPS clamp, or by forcing vSync externally.

Hopefully this will give people a little heads up.

But the alternative is a massive amount of input lag, making control seem sluggish, unresponsive and awkward.

This is why I'm waiting for the frame rate related bugs to be patched before I even reinstall the game.

My input lag is pretty much gone. I've got VSync Enabled + Forced Triple Buffering + FPS capped at 45. I also increased the sensitivity a bit and disabled mouse acceleration.

This is true no matter what, v-synch on or not. The sensitivity of Y is effected by framerate, sluggish when lower and fast when higher. It's a bug (one assumes).

Of course. However it's a lot less noticeable with vSync enabled for me.

Even when Vsync is enabled, I personally have my days starting and ending at 11pm, most likely due to the small fluctuations you get with Vsync.

LOL! Brilliant!

I've spent the last two days thinking the 'pots n pans' flying about might have been some ghostly side quest I'd stummbled upon. My guy even started levatating, the screen turned greenish and my weapons kept falling off!! You couldn't script this kind of stuff could ya.

I also thought FRAPS was winding my up when I reached 150+ fps while 'pot-holing' erm.. I mean cave exploration.

I can honestly say I've spent more time with my nose in those bloody ini files than I have playing the game. I've got a i5 760 at 3.8Ghz, 5870 stock and 8gb 1600 RAM, and over the first couple of day with Skyrim I was running at 1600x900 on med settings just to get an hour without a CTD or mostly Display Driver Stopped Responding.

However.. I think I've found my solution.. Large Memory Address dl. Amazing! My entire ini settings list has rocketed and up to now (10+ hours) no CTD's. I'm now running at 1080p, Ultra with all the sixy ini tweeks and Vsync. FRRAPS is looking smooth at 60fps with small dips in npc heavy areas. I've pushed my memory cell buffers up too. I've not tried UGrids as yet. Also try adding '+fullproc' to the Skyrim properties box in Steam.

I can also recommend turning off all auto-save functions as many of my CTD were just after a load. You quickly learn to manually save when needed.

Desptite this all..... What an amazing game!

That's some pretty shoddy programming there...

Never use the games auto save...ever.

Its a hard fact that if you continually write into the same file over and over, its bound to corrupt.

So forced vsync in CCC or Radeon Pro is not enough? Why would it not be?

It seems it's something to do with the engine having iPresentInterval set to 0. This, coupled with FPS highs seem to be causing a whole host of issues.

Not arguing with that, but there are 3 auto saves now (and it looks like there's a .ini setting to change that number), in addition to the quick save. So if one of them corrupts, you'd still have two more back ups. Those auto saves actually saved me after a freeze once. It saved right after I exited a dungeon, followed by a freeze. Had to force reset my PC. Despite the auto save being just before the freeze, it loaded up and played fine (as fine as it'll get at the moment anyway).

But I agree that everyone should make manual saves after every play session at least.

I'm having a hard time confirming this to be the case...

The game now runs at a level where it's pretty playable, where one of the tweaks was the "iPresentInterval=0".

Tried a few times now with the value set to both 1 and 0, and can't really say that the physics have been improved or changed in any way.

Noticed my days change at 11PM, but I guess that's "by design"?

Anyway, would be interesting to see if someone could confirm this fixes the physics, as that's the last really annoying bug (or whatever it is).

I've had vsync off for my entire game so far, and I haven't had any of these problems (maybe the time one, but I haven't been paying attention to when the days of the week change). You can keep vsync off, just use an external FPS limiter (like this http://www.skyrimnexus.com/downloads/file.php?id=34) and keep it at or under 60. I keep mine at 30. That should stop the physics from going crazy.

Skyrim.ini, not SkyrimPrefs.

I am seeing alot of talk about how Vsync disabled causes bugs, and obviously you addressed them. I have not ran into these bugs, and I have had vsync disabled since day 1.

I now understand the Physics bug, but that is not related to Vsync at all, I had that bug even before I did the preset interval ini tweak.

Good post. Yeah, my Vsync only changed when I made the change in Skyrim.ini . I don't know if the identically named setting in Skyrimprefs.ini is a copy from Skyrim.ini, or from the templates used by the launcher when you don't have skyrimprefs yet. Or if the line just isn't used at all in Skyrimprefs.ini , while the one in skyrim.ini is...

I'm using d3doverrider to force vsync, i wonder if that interferes with the game's iPresentInterval=1 ? I'll test to see if triple buffering still works next time if d3doverrider does not force vsync (and tries to use the game's vsync setting), but forces triple buffering only. I want to avoid as many stock game bugs as possible, because when the CK comes around each mod could be a source of its own bugs.

Edit : I'm also curious to know whether framerate capping does anything to mess with game timing. I have noticed spike traps happening out of sync with their sound effects (or the other way around, I don't know which) with my FPS capped at 45. But I don't know if that already happened without FPS capping. I have played with the fps cap for maybe 10 hours total but am still looking out for weird bugs since I am used to Oblivion/fallout eventually getting weird bugs later on in play as I discovered different things.

Its just like the ini files for Fallout 3:


And yet, in that tweak guide, ipresentinterval is in the fallout ini, not falloutprefs.

Anyway, I just tested it and I still get the same results, even with vsync disabled/enabled and even with the line completely erased.

I dont mean to be rude OP, but I really doubt Vsync is causing the bugs you addressed. I dont even have a great system and yet, like I said, I just tested it out.

Remember, it is skyrim ini, NOT skyrimprefs

With Vsync disabled/enabled/ipresentinterval erased:

Water was fine

I discovered the time bug you mentioned, but I had vsync on and tried it without the ipresentinterval line

Only physics bug I encountered was when a Giant hits you and you go flying. I had that bug before I messed with the ini files

And the x/y axis are fine with me.

Again, I do not mean to sound like a dike but I am just telling what I saw, vsync had nothing to do with those bugs.

...how can the time of day, which is a function, be affected by your FPS locked to your refreshing rate? o.O

Zhayne: Bad coding or porting artifact, most likely. Neither Oblivion or Fallout 3 had that happen.

I just checked, and it appears that my clock has gone out of sync due to this bug. Too late to change anything now, I'm afraid. This might be a game-ender, since it can cause so much havoc with AI scheduling.

I am now debating a full-on restart.

Its a Bethesda game, can never be sure what will cause what problems half the time.

the y sens is always tied to your FPS, granted you won't feel it if you have 60hz monitor, you'll however feel it if you have a 120hz

also, if npc's are sitting on a chair or standing close to objects you'll get this sound at 120 fps http://www.youtube.com/watch?v=KfafLK_fhp0 (Lydia sitting on a chair in the Whiterun house) , object flying around doesnt seem to happend at 120 fps, but does at atleast 200+

so 120 hz:ers need to limit the fps to get a non-buggy game.

Why disable vsynch if you're going to enable an outside fps lock?

As I posted in another thread I have the bug where the day name only changes at 5pm, and this is the case with or without changing "iPresentInterval".

However I've clocked lots of hours with it set to 0, so maybe it can't be reversed by changing it to 1 again?

less mouse lag with a fps limiter at 60 than vsync at 60

Sad...it' feels like we get the middle finger again. I wonder why there is so much console hate.