Annoying C1E/EIST program issues - any solutions?

Hi all, I have the following system as our 'front room' htpc/downloads machine;

E6320 on EP35-DS3L
2Gb DDR2-800
8800GS
Vista 64
Connected to 15" Dell LCD (primary) and 1370x768 LCD TV, using dualview - extended desktop with separate resolutions.

The machine is set up with all the energy saving functions on, i.e. C1E, EIST and temp controlled fans, but also with the dynamic overclock feature set to I think the 3/5 setting - might be 'sports' for example.
In practice it means that it will idle the chip at 1600Mhz by dropping the mulitplier to 6, and will overclock up to about 2.3Ghz using the FSB when required - great.
However it seems that certain programs just don't get along with this. Windows Media Player, for one seems to have problems. When playing avi files there will be half second pauses every 15 seconds in the video playback caused by the CPU multiplier being adjusted up for a second. These are regular and frustrating, and you couldn't sit through a movie like that. I have tried with C1E and EIST turned off/on in both combinations and it only settles down with both off (and with the overclock option off too as somehow this also causes the same proiblem!), however VLC plays flawlessly with both on, even though both players use <30% of the CPU when playing an .avi.
Is this something I just have to live with? And either turn all the dynamic clock stuff off or not use the programs that have issues with it?
I guess its not making much of a difference in power consumption between 1.86ghz @ 1.31v and 1.6Ghz @ 1.16v.