Depends on the benchmark I think. In this case it's probably close. Apple is cagey when it comes to power draw or clock metrics but I believe the M4 max has been seen drawing around 50W in loaded scenarios. Meanwhile, Phoronix clocked the 395+ as drawing an average of 91 watts during their benchmarks. If the performance is ~twice as fast that should be a similar performance per watt. Needless to say it's at least not a dramatic difference the way it was when the M1 came out.
edit: Though the M4 Max may be more power hungry than I'm giving it credit, but it's hard to say because I can't figure out if some of these power draw metrics from random Internet posts actually isolate the M4 itself. It looks like when the GPU is loaded it goes much, much higher.
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Depends on the benchmark I think. In this case it's probably close. Apple is cagey when it comes to power draw or clock metrics but I believe the M4 max has been seen drawing around 50W in loaded scenarios. Meanwhile, Phoronix clocked the 395+ as drawing an average of 91 watts during their benchmarks. If the performance is ~twice as fast that should be a similar performance per watt. Needless to say it's at least not a dramatic difference the way it was when the M1 came out.
edit: Though the M4 Max may be more power hungry than I'm giving it credit, but it's hard to say because I can't figure out if some of these power draw metrics from random Internet posts actually isolate the M4 itself. It looks like when the GPU is loaded it goes much, much higher.
https://old.reddit.com/r/macbookpro/comments/1hkhtpp/m4_max_...