Originally Posted by Homeles
In this case, it seems that the savings from soldering a chip to the system board outweigh the savings from flexible upgrades and individual component replacement. Caches used to be separate form the CPU — now they're integrated. Memory controllers are now integrated. Graphics are now integrated. Someday we probably won't have anything that resembles a motherboard at all.
Caches must be integrated because cache control is important for out of order computation and for proper branch prediction/recovery.
Memory controllers might work faster when they are integrated, but they put much more strain on CPU and memory manufacturers to have properly compatible components, and memory controllers on chip can cause stuff to be burned out. When you look at XQ chips they have still insane RAM bandwidth, just moving it to CPU changed stuff to be cheaper to manufacture, thus the bandwidth was available even for low end CPUs.
Graphics card integrated on chip was choice of Intel, and possibly AMD, they work better when they are separate. As long as they can be disabled when not used, they only make CPU more expensive. When they are not completely disabled, they wreaks havoc during overclocking. (Which is the reason why I liked these celerons, or E2xxx, or E5xxx chips better for overclocking. They have less cache, thus less thing can go wrong. 200 MHz better overclock would completelly kill the difference in cache, and 400 MHz higher overclock... YES. Also less strain on MB, and possibly lover voltage during overclocking, especially when that chip was moved into lower category for bad bus part. Then Intel locked low end chips.)