Don't have Fallout, but I do have Oblivion in my library. Last time I tried it was with my 60Hz monitor though.
It seems like same thing applies to Oblivion, game vsyncs to 144 FPS with default iPresentInterval=1
and with 0
it goes way beyond. However there doesn't seem to be any problems in the gameplay. Vsync is option on launcher and disabling allows unlimited frame rate I'm guessing there's no problems with that game running that at high frame rates.
So basically they simply took out vsync option from launcher to fix massive frame rate problems introduced in Skyrim and were done with the issue but didn't take high frame rate displays into account? Actually with Skyrim iPresentInterval=0
still keeps vsync on at least for me and there's no setting called iFPSClamp and adding the value under [General] has no effect to anything at all. It does look more and more like they "fixed" frame rate related issues with vsync instead of cap.
EDIT: I can force vsync off with nvidia panel, so I get ~200 FPS and with that same Skyrim intro I'm flying trough sky like santa claus.