G400m DualHead Performance Again, Again

[SunDriedGrapes]

I've been away from my g400-equipped box (not to mention the internet, and technology in general) for the past year or so, so apologies if all this has been adequately covered before. I'm sure it has, but the boat left and I wasn't on the boat. Feel free to link to link me to an old discussion and call me a 'lamer' for not spending the next three quarters of an hour searching through MURC's archives

Pdesk 6.51 claims to let one en/disable dualhead without rebooting (The Holy Grail!). It still asks me to reboot, though (hhm). Has anyone done exhaustive tests and benchmark (so that I don't have to) and ascertained the performance hits of the new dhead configurations allowed by the newer drivers. For example, if I were to disable 'extend desktop', and rebalance AGP and texture memory say 100% to the primary display, how close would this bring me to single-head performance?

What is the biggest Lief Ericsson?

[Kruzin]

It's not that you can enable/disable DH entirely without rebooting. You can switch DH modes (clone, extended desktop, etc.) without a reboot. If you want to completely disable or enable DH, it will still require a reboot.
Just un-extending the desktop from the second display still leaves DH enabled, and will still show a performance hit compared to SH mode.