The Problem is tweaking the System for GPU (throughput/latency between GPU/system memory) Performance (CPU clocks/async) and tweaking it for CPU performance are different especially for discreet systems in Systems like Sandy Bridge or Brazos you wont have these problems, and you have to differentiate between Video Engine Load and GPU Load Video Engine Load isn't problematic @ all. And especially for lower Bandwith systems like Laptops/Netbooks you should always try to use DXVA instead of NVcuvid (Nvidias Video API falsely called CUDA by many).
And yes getting CPU playback flawless on a High Performance Dual or Quadcore is rather easy if Multithreading is supported, and granted their are still a lot of issues with GPUs especialy OS wise we have no real preemptive multitasking yet on the Driver side not with WDDM 1.1 and it still floats in the Air how the Plans are here from Microsoft and GPU Vendors for Windows 8 we might see the first changes
I hope we soon get some more information what happened in those regards
http://download.microsoft.com/downlo...ri103_wh06.ppt is a little outdated these days
We are surely not their yet and so i will never be surprised about user who report frame drops
especially those who doesn't take other problematic stuff with this into account like low timers and applications especially like Aida,Afterburner or other Hardware poolers that can interfere here running in the background, unfortunately Windows is no RTOS :P
I hope @ PDC this year we finally get a update on the state above WDDM 1.1
and im a little surprised to hear nothing about it from the Windows 8 milestones yet
seems no one looked as far down and is only interested in the stuff above which is imho absolutely uninteresting consumer stuff.