Even in multithreading scenarios Bulldozer could easily lag behind Intel. This is because each pair of cores shared floating point execution units, as well as other resources. Under many circumstances, the performance profile became more similar to a quad-core CPU with HT than an octo-core CPU... Which meant it was all around shit.
There's one particular game, BeamNG.Drive, which I remember had *tons* of people bitching about their performance with Bulldozer. It's a car simulation game, with real-time soft body physics, and runs each vehicle simulation on a single core. In theory, this gives you rather linear scaling with core count for the number of vehicles you can run at the same time in-game. That was not the case with Bulldozer. Turns out the floating point calculation load in BeamNG is yuge! The seething and malding from so-called superior 8-core CPU havers was delicious.
There was even a class action lawsuit over false advertising, describing Bulldozer as octo-core - and AMD lost.