Re: LUKS/ dm-crypt/ ext4 appears to be single threaded
I've frequently found performance in Linux while running an IO intensive process to leave something to be desired, though I've only delved as deep as changing IO schedulers to resolve this. I'll be interested to hear what you find.
As for hard drives with built-in encryption, I'd suggest avoiding them unless you have some reliable assurance that they work as you believe they do. It's just too easy for an invisible implemention detail (mistake or intentional) to result in compromised security.
dm-crypt mailing list