Not all of them were known back then obviously, but there were definitely known timing-info-leak flaws with Pentium 4 hyper threading[1], its remarkable on that

Not all of them were known back then obviously, but there were definitely known timing-info-leak flaws with Pentium 4 hyper threading[1], its remarkable on that basis that the modern class of execution timing exploits has taken so long to arise, considering their approach and concept really isn't fundamentally any different. [1] http://www.daemonology.net/papers/htt.pdf http://www.daemonology.net/papers/htt.pdf by none other than our resident cpercival!