The high failure rates of the Xbox 360 did not help.
"Microsoft did not reveal the cause of the issues publicly until 2021, when a 6-part documentary on the history of Xbox was released. The Red Ring issue was caused by the cracking of solder joints inside the GPU flip chip package, connecting the GPU to the substrate interposer, as a result of thermal stress from heating up and cooling back down when the system is power cycled."
IBM's Power was the only logical option at the time.
These consoles were being designed around 2000. Intel and AMD weren't partnering on bespoke CPUs at that time. I don't even think AMD would have been considered a viable partner. Neither had viable 64 bit options and part of console marketing at the time was the ever increasing bit depths.
Prior console generations had use MIPS which wasn't keeping up with ever increasing performance expectations and players like Toshiba and Sony were looking for a higher performance CPU architecture. IBM's Power architecture was really the only option. Sony, Toshiba, and IBM partnered to develop their a new 64 bit microarchitecture called Cell.
Microsoft's first console was basically a PC and that's how everyone saw it. The 360 was an opportunity for Microsoft to show that it could compete with the big boys. It was also an opportunity to keep a toe dipped in RISC, because it had dropped support for RISC CPUs with Windows 2000.
What wasn't viable?
Previously:
Speculative execution, however, can cause less problematic side effects. For instance, a speculatively executed load or prefetch will usually actually prefetch which will pollute the cache, TLB, etc., and reveal side-band information, but that is a performance problem and perhaps a subtle security flaw, not a correctness bug like this was.
In the last week Raymond Chen on his The Old New Thing mentioned the concept of delay slots on some CPUs.
It sounds like a similar thing, just formalized so it’s not a bug. Knowing that the instruction after a branch always executes, regardless of if the branch is taken.
Do I have that right?
With enough sophistication, physical access is more powerful than root access, no exceptions.
