Are you talking about the replacing the Windows processr.sys driver with amdk7.sys?
I've read lots of discussion about which one should be installed for AMD CPUs (especially mobiles) but I don't think it's been proven which one is better for desktop CPUs. Almost everyone including myself leaves it at the default processr.sys driver but either should work fine. The exception is AMD mobiles in laptops must have amdk7.sys for PowerNow to work properly.
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