You might have allready figured this out by now, but you do not have to revert back to MS's CPU driver. When the power scheme is set to always on, Windows doesn't attempt to do any dynamic switching. Also, the driver from AMD isn't what determines what voltages and frequencies are used. The BIOS is where that information comes from. The CPU driver queries the BIOS and obtains the necessary information to populate a table that is then used by the ACPI feature of Windows XP to control the cpu speed. Sager doesn't give us the option of adjusting these settings like alot of desktop motherboard manufactures do. AMD does publish guidelines as to what the CPU should be running at, but it is still up to the pc manufacture to implement those settings within the BIOS.
So, you can use either driver if you want to. I lthink people should use AMD's latest so that they can revert back to stock settings if they want to, and still get some benefit of Cool N Quiet.
As for the lower end, it does make a difference in going to .8 volts. You just don't notice it as much because there are other components of the notebook that are consuming so much power that the 10 watts or so if shaves off are negligable. It will add up in the long run, however.
I will let everyone in a little early on what I am attempting to do with my 4750. I am trying to acheive over 3 hours of battery life under "normal" use. Some will think that is a crazy idea, but I don't think so. The main reason this notebook consumes so much power is that Sager chose not to implement a few power saving features. The first feature they omitted is ATI's PowerPlay feature. I won't reiterate here what this does, but it can have a huge benefit. There isn't a good excuse on their part as to why they didn't implement this (they aren't the only ones, though.) Second, they didn't implement any hard disk power management features. This I can give them a pass on, because there are so many hard disk choices, and each manufacture has their own power management techniques.
In doing some research, Hitachi's new 7K60 7200rpm has some awesome power reduction features, but they aren't being realized on our notebooks.
So here is my plan:
1. Reduce the CPU power requirements to as low as possible while still being stable (of course)
2. Implement ATI's PowerPlay feature. Set to disable most features if not running a 3D app/game.
3. Allow the hard disk to go into a low power idle, and then power off completely when not used. Windows XP is itself a problem here, because it is constantly accessing the drive. It is even worse with SP2.
Step 2 is the hardest. Step 1 is done, and Step 3 is almost done. I will post information on the HDD power management when I get it working right.
(sorry about the spelling, I don't have time to check it, so don't complain about it)