Currently, I think the PS3's processor is more powerful than current quad-cores, although much of its power goes to waste. I have however heard of scientists using multiple PS3s to process data instead of regular supercomputers, based on the ratio of performance to cost.
When it comes to graphics, most games are designed to run at 720p (1280 x 720), and are upscaled to 1920 x 1080 for display on capable TVs, so the resolution is lower than at what most PC games are run. Then there's also optimisation for the specific console hardware, which is much more difficult for PCs due to the myriad of configurations. Furthermore, most would sit at least 5 feet away from their TVs compared to 1-2 feet from their monitors.
The X360 however does have 10 MB of eDRAM, which helps its framerates while having full screen anti-aliasing enabled.
When it comes to graphics, most games are designed to run at 720p (1280 x 720), and are upscaled to 1920 x 1080 for display on capable TVs, so the resolution is lower than at what most PC games are run. Then there's also optimisation for the specific console hardware, which is much more difficult for PCs due to the myriad of configurations. Furthermore, most would sit at least 5 feet away from their TVs compared to 1-2 feet from their monitors.
The X360 however does have 10 MB of eDRAM, which helps its framerates while having full screen anti-aliasing enabled.