If I perform the mod, then I want to go back to mining at 600-850mhz again for some reason, that still works? (but still using 2W more?)
Of course, the power consumption is directly related to core voltage, so frequency does not matter much in that regard.
If you want to hard mod the voltage to 1.25v, and use different miner software:

This allows you to have a stable overclock without the special version of CGminer and voltage=1???
Yes, up to 950 MHz would be stable, I am using cpuminer.
Excellent! I knew there had to be a further hardware mod 'jumper' to get stable operation at 1.25V without converting over to a different mining program. I'm using cpuminer and am quite satisfied with it since I have a very small farm anyway.
One thing that still bugs me though is having to reset the USB ports every 24+/- hours.
Anyway, I can make the jumper mods easily as I own a professional Weller soldering station with adjustable temp, very fine tip assortment, de-soldering etc. So no problems making the mods.
I wonder though, have either of you chaps tried seeing if any of the existing header's pins correspond to either of those two jumper points? Or is that header simply a serial port connection. I haven't studied the schematic yet so I realize this may be a stupid question.

Anyway, I'm very interested in this mod for my own miners. Having done years of laboratory level R&D in electronics, this stuff is a piece of cake!
Have the two jumpers stabilized the GS units well enough to overclock above 950 yet?
Man, if we can get these little buggers running at 500KH/s, that would be fantastic!
But, 400KH/s ain't nothin to laugh at either

I have all my units fanless now. If necessary, I can simply use 1 or 2 fans to blow air on the fins indirectly which will of course keep them running cooler.
I might be interested in making this mod for others too if the money is right.
They'd be responsible for all shipping costs and insurance etc. etc.
I'll figure out what is a fair price to charge per mod later if anyone shows interest.
Thanks for coming up with this mod. Sure saved me some time and hassle.

Wolfey2014