I would not bother, i used one on a p4 3.2, yes it was quiet but it was not much cooler than standard heatsink.
For an AMD A64 try the arctic cooling Freezer 64 .
Knocked at least 10c off my loaded temps A64 3500 newcastle even when using 1.7 volts.
And its near silent, psu fan is louder than the freezer 64.
Its also cheaper than the Zalman.