7ms Present() fact-finding mission

gistfile1.txt

The problem: Every 9-10 frames, Present() takes a huge amount of time.
Original tweet with Parallel NSight screen shot: https://twitter.com/rygorous/status/245270559020171265

Short but representative log of Present() timings: (frame number:time taken)

4721: 7.628466ms
4722: 0.294534ms
4723: 0.340265ms
4724: 0.282702ms
4725: 0.283661ms
4726: 0.282702ms
4727: 0.321717ms
4728: 0.286859ms
4729: 0.289417ms
4730: 0.284301ms
4731: 7.619512ms
4732: 0.291656ms
4733: 0.287818ms
4734: 0.291976ms
4735: 0.335149ms
4736: 0.290377ms
4737: 0.282382ms
4738: 0.296453ms
4739: 0.335788ms
4740: 0.283341ms
4741: 7.578897ms
4742: 0.291976ms
4743: 0.342504ms
4744: 0.291016ms
4745: 0.284940ms
4746: 0.285580ms
4747: 0.320438ms
4748: 0.286219ms
4749: 0.289098ms
4750: 0.285260ms
4751: 0.325874ms
4752: 7.584334ms
4753: 0.288778ms
4754: 0.284301ms
4755: 0.341225ms

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Suggestions so far:

@milesmacklin: "Haven't seen that one before. GPUView might have the answer though"
-> GPUView keeps crashing on me trying to load the ETL files. Small repro case found,
  support request sent, waiting for an answer :)

@alphanew: "Last time I ran into this, it vanished whenever I disabled Windows Aero Desktop.
  Never found out what exactly caused it, though."
-> Nope, not the reason: Get the exact same behavior with Windows Classic theme.

@xoofx: "you get this in full screen?"
-> Yes, I do. (Although I typically run windowed for Debugging, I've verified that this
  also occurs in full-screen mode)