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macrumors G4
Jun 18, 2017
Don't worry about it. From the sounds it, it is a rare occurrence and applies to only specific usage, and even most people who do use their computers that way will not experience it.

Apple will update their firmwares and/or macOS to address this as necessary.

If you're really worried about it, you can disable HT (although that doesn't apply to your i5). However, in my case that would apply to both my MacBook and my iMac but I'm not going to bother. For the MacBook it would affect performance too much, and for the iMac, I am just not going to worry about it regardless. ;)
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macrumors 65816
Dec 9, 2014
It's sort of the devil you've seen vs the ones you haven't.

CPU's are chock full of bugs, just like anything else. The good news is that most of the bugs only occur when you do meaningless or wildly obscure instruction sequences, because the meaningful ones have been flushed out with testing. This bug falls into a bit of a grey area, you have to be doing something weird and obscure but not totally nonsensical to provoke it. It's hard to not worry about it, but that would be my advice...

Maxx Power

Apr 29, 2003
The i5s used in the Macbook Pro series are all 2-core, 4-threads (e.g., any 13-inch Macbook Pro). In other words, all the Skylake and Kaby Lake i5s of the mobile variety (so not iMacs and older series of Macs) are all Hyperthreading-enabled. Intel is driving away the distinction of Hyperthreading between its i5 and i7 CPUs. Last rumor I heard on this topic, Intel is eventually going to add Hyperthreading to desktop i5s in the future.
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