So my PC runs 5% slower because someone could break into my house to get physical access to decrypt memory? OK sure, but not my top concern, and a bad tradeoff for the lost performance. And not only fair, but completely accurate to describe TSME as non-critical for *most* consumer desktops. I'd go as far as to say useless and counter-productive for most, but not all, consumer desktops.
So you turn it off by default in BIOS and allow those that feel it's useful to them to enable it, and you solve for both sides of the problem.
Does it run slower? I'd expect dedicated hardware to do that encryption/decryption, in which case there should be no difference.
I think it's more a reference to Spectre and Meltdown and Rowhammer and a bazillion other hold-my-beer attacks that have never, ever been used in the wild but that everyone pays the price for by having their CPUs slowed down by the countermeasures. Applying Unicorn Repellant is fine when there's no cost, but it definitely has a cost in these cases.
How can you be so sure they have never been used in the wild? Surely not all uses of them get reported...
The same way I'm fairly sure that no-one's ever been attacked by a unicorn. There could be lots of unreported attacks, but I'm pretty sure there aren't any actual ones.
What we do have is millions of actual, real-world attacks (see any security body's top-ten list) that we aren't mitigating because we're too busy focusing on silly attacks that no-one ever uses.
I had read there was a ~5% slowdown with it enabled.
If it's not your top concern, you're probably a government employee with full security clearance and the "consumer desktop" doubles as a pirated game rig, top secret NAS and Twitter battle box.
The 180 is incredible to see though. I remember when enforcing FDE was all the rage bc well, shit gets stolen. This stuff was a critical concern then. Apple got raked over the coals for months because they did nothing to prevent shoulder surfing (as if a phone could).