will this work for a 850w power supply?

This will work for any power supply. The cable is definately a little thicker and I imagine would last you a very long time. I feel safer using a 14 AWG over the standard 18AWG.

Is this compatible with an Apple computer from 2008?

It is a premium (14 AWG) universal power cord that is compatible with standard personal computer power supplies that utilize 3 prong connectors (google NEMA 5-15P to IEC320C13) to see an image. This cord should work with any computer commonly found in use.

Questions & Answers: C2G 03131 14 AWG Premium Universal Power Cord (NEMA 5-15P to IEC320C13) TAA Compliant, Black (6 Feet, 1.82 Meters)

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