The NUpowr card uses approximately 7.5 Watts. This is essentially the same, or less, power draw as the 68040 card it replaces.
There are three versions of NUpowr which differ only in the amount of RAM they have soldered. NUpowr is available with 0K of memory. This version is for users who possess 16MB or 32MB memory modules. There is a 4MB version of NUpowr for users with 8MB, or larger, memory modules. Finally, there is a version with 8MB of RAM soldered for those users who have 4MB, or larger memory modules.
NUpowr has been found to work with existing PowerBook 500 memory modules. This of course assumes that the memory was designed correctly.
The required version of the Operating System can be installed two different ways. While the PowerBook 500 computer still contains the 68040 CPU the user may install System 7.5 (They will need to use Custom Install and chose the Universal System for any Mac). They may then run the 1.0 updater and then 2.0 updater. At the completion of 2.0 Updater installation their "About This Macintosh" window will inform them they are running System 7.5.3 with System Update 2.0. The second method of obtaining the correct install is to simply install System 7.5.3.