If you remove the SPE's from the equation (which many developers did) the PS3 has a much slower 2 Ghz Dual Core PPC64 CPU, while the Xbox has a 3.2Ghz Triple Core (6 thread) PPC64
The extra threads aren't directly as useful as games back then were almost entirely single-threaded, a trend that has only begun to really change course in the last decade or so (partially due to the Xbone and PS4 having anemic Bulldozer derived CPU's that had weak single-thread performance)
IIRC it's not even a dual core but a single core with two threads.
Sony really dropped the ball with the PS3 chip.
It's a shame they invested hundreds of millions or even billions in this new, hot, complicated to use chip, only for it to be completely surpassed by off the shelf x86 parts.
Sony though the chip would be so good they could sell it to be used in super computers for years to come, but by the time it was out, x86 had basically caught up and no customers cared about buying their cell processor.
The winner of 7th generation was clearly Nintendo with their Wii: over 100 million units.
And the funny thing is 2nd place: PS3! Just at the end of generation it managed to oversold X360
Piling onto that with "we're getting rid of game sharing or the resell market" and "our new console is going to be your entertainment hub, i.e. it's going to be jammed full of shit most gamers don't want!" and the launch was just... ugh.
XBox vs PS2: XBox was faster, but PS2 launched earlier, was cheaper, and had more games, so won the generation.
XBox 360 vs PS3: Sony reacts to Microsoft by making the PS3 more powerful than the 360 and more expensive. Microsoft reacts by getting more games and really doubling down on Halo (the biggest draw to XBox back then). XBox wins the generation.
Note: this is from memory, didn't check sources!