Most people has this issue and its been present since day 1 of release since i can remember:

http://www.youtube.com/watch?v=IUHvV80xEbQ

I dont know if this issue is present on nVidia cards or if its caused by Skyrim engine, but since AMD decided to drop monthly updates (which is good in a way) maybe we should to report and kindly ask AMD to check this issue in the following link:

http://www.amdsurveys.com/se.ashx?s=5A1E27D20B2F3EBB

Its kinda getting worst in my System:

AMD PhenomII x4 810 (OC 3.1Ghz)
AMD Radeon HD 5770 1Gb
6Gb DDR3 1333Mhz
800 Watts PSU
Win 7 x64
Skyrim Ultra Detail 1280x1024
AF/AA x2

Or maybe report this issue to Bethesda?

This is quoted from a youtube video I looked at and it totally fixed it for me. SOURCE: http://www.youtube.com/watch?v=orcXIA3gnBg

- Updated tweak: Go to SkyrimPrefs.ini and make sure these settings are under the section [TerrainManager]:
fTreeLoadDistance=75000.0000
fBlockMaximumDistance=500000.0000
fBlockLevel1Distance=140000.0000
fBlockLevel0Distance=75000.0000
fSplitDistanceMult=4.0000
bShowLODInEditor=0
What it does is that instead of decreasing the distance at which LOD has high quality, it increases it, thus forcing more detailed LOD to be further away. The downside is less FPS, but it's hardly noticable.
In conjuction with this, you can also set fSkyCellRefFadeDistance=500000.0000 in SkryimPrefs.ini and in Skyrim.ini under [General] section (if these settings doesn't exist already, just add them to the Skyrim.ini under the [General] section) change these settings: uGridsToLoad=7 and uExterior Cell Buffer=64. Beware when increasing the uGrid and Cell Buffer though of the performance and stability consequences it can cause. You should have a look at this thread (http://www.gamesas.com/topic/1274926-ugridstoload-skyrimini-comparisons-and--explanation-default-57911/) if you think about increasing the uGrid. Thanks to torminater for this updated tweak.
I also recommend having fNearDistance=25.0000 under [Display] section in Skyrim.ini in conjuction with this above .ini tweak. Together it should decrease your mountain flicker / Z-fighting a lot, if not almost completely.

To get a definite fix for the mountain flicker / Z-fighting, we will have to wait for talented modders or Bethesda.

If you know a fix for the mountain flicker / Z-fighting, I personally beg you to please comment it in this video. I personally, and I'm sure other people who have this problem, would appreciate it as well.

For more information and discussion about this problem, see the relevant thread at the official Skyrim forums: http://www.gamesas.com/topic/1336456-mountain-flicker-z-fighting/