The very first graph (Cinebench R15) is wrong. i7-8700K does not score 3314 or even 2515 on this benchmark [1]. i7-7700K numbers are also way off. Not sure what happened here, but I can't take any other measurement they published seriously. This is more useful:
https://www.phoronix.com/scan.php?page=article&item=sandy-fx...
If you're using an overclockable workstation CPU, the good news is that turning SMT off gives you additional ~200Hz of overclocking headroom. Modern Intel chips are thermally limited when overclocking and turning SMT off makes them run a bit cooler. My i9-7900X overheats over 4.4Ghz, but with SMT off it's comfortable at 4.7Ghz on air (Noctua D15).
> I can't take any other measurement they published seriously.
Here's another problem with the article:
> Microsoft is pushing out OS-level updates [...] However, this doesn’t mitigate the problem entirely, for that we need motherboard BIOS updates and reportedly Intel has released the new microcode to motherboard partners. However as of writing no new BIOS revisions have been released to the public.
That's wrong - microcode updates can be successfully applied by either the OS or by the early-boot firmware, you do not need a BIOS update (just apt update intel-microcode).
No. I have to look it up to be certain but I believe that MS did not want to patch CPU microcode during boot and tried to leave that to the firmware. But - I may be wrong here - this stance changed with Spectre and Meltdown and Windows does indeed patch microcode during boot on affected CPUs. However, I don't think there is a way to apply a user-specified patch. The update has to come from MS.
Microcode is stored in volatile memory on the CPU. Updates are applied on boot, every boot. "Downgrading" is as simple as not applying updates, or applying an older update.
Loading microcode on a CPU (without patching the firmware) takes effect immediately. The update is lost immediately upon reboot and must be reapplied each time.
Just note that the perf loss is 20-40% in their benchmarks, so in your case, you'd need to bump that 4.4Ghz to 5.5-73.GHz, which is a tall order.
In any case, the article is worst-case FUD-like nonsense. No idea what the eventual perf loss will be, but it's a safe bet it'll be less than that.
Consider that it's likely safe enough for 99% of usages for the OS to allocate CPU cores to processes in pairs, and that would incur only a small penalty. And something smarter is almost certainly possible, too.
If you're using an overclockable workstation CPU, the good news is that turning SMT off gives you additional ~200Hz of overclocking headroom. Modern Intel chips are thermally limited when overclocking and turning SMT off makes them run a bit cooler. My i9-7900X overheats over 4.4Ghz, but with SMT off it's comfortable at 4.7Ghz on air (Noctua D15).
[1] https://www.guru3d.com/news-story/intel-core-i7-8700k-benchm...