An update from the Reddit comment that's not on the first page of the macrumors thread:
[Edited to add note: From messages others have sent me, it seems that this MSR is actually not Intel's default, but rather this is what Apple has been setting the MSR value to on all intel chips in Macbook Pro and Macbook Air for a number of years ... This is just the first chip to actually be capable of drawing enough power for this to matter. Previous chips just couldn't draw that much power, so they never hit the VRM limit before]
I think it's the other way around - MacRumors post was July 22nd at 4:57pm while the Reddit post was July 22nd at 4:36pm GMT-7. (I can't tell if I'm being messed up by time zones though as that doesn't appear on mouseover for MacRumors)
[Edited to add note: From messages others have sent me, it seems that this MSR is actually not Intel's default, but rather this is what Apple has been setting the MSR value to on all intel chips in Macbook Pro and Macbook Air for a number of years ... This is just the first chip to actually be capable of drawing enough power for this to matter. Previous chips just couldn't draw that much power, so they never hit the VRM limit before]