The most obvious difference from the 10X Quiet is the plastic top cover and integrated fan controller used on the 10X Extreme. The controller works while directly connected to the cooler, or can be detached and used with the included extension cable which is approximately 15" in length. Power for the fan and controller is supplied from a 4-pin cable that comes out of the top cover. It would be nice if the power cable came out of the bottom of the Extreme for aesthetics and better cable management. It appears as though you could reroute the cable behind the fan bracket, which should be fine as long as you keep any slack out of the fan blades.
Rather than the Quiet's clips, the Extreme's fan is attached to a plastic frame with four screws. The frame clips into notches in the fins and is attached to the top cover via screws. The 4-pin PWM fan is rated for 1,000 - 2,150rpm and 20 - 39dBA when used with the included controller. This is slightly faster and louder than the Quiet's fan, and current draw is rated at 0.40A as opposed to the 0.25A, however again Zalman does not list airflow numbers for either fan.
The design of the Extreme base is identical to the Quiet, the only difference is in the nickel plating. There still appears to be slight gaps between the heatpipes and base, however there is no excess solder flash spattering the pipes like we saw on the Quiet. Perhaps the Extreme undergoes some additional quality control prior to being plated, or maybe it is purely coincidental that our review unit shipped like that. Either way it should not affect the cooling ability of the heatsink as long as there is good contact between the heatpipes and base.
Speaking of cooling ability, let's get these units installed and tested.