Wednesday, October 15, 2008
Something interesting about modern CPUs
As TheRaven64 pointed out nicely on slashdot, low-cost CPUs are more often the result of a faulty construction than of a brand new design.
Here is how he puts it (in comment 25384737:
A modern CPU is quite big and contains a lot of components that aren’t essential to the operation of the chip. If you disable these, you have a slightly less good chip without the engineering cost of designing a entirely new die layout. AMD takes this to extremes. Their Opterons have 4 cores, three hypertransport connections and a load of cache. If there is a manufacturing flaw in the cache, they are sold as a model with less cache. If it’s in the cores, then they are sold as three, two, or single core chips. If it’s in the HT controllers then they only support 2- or 4-way multichip configurations. Intel’s 486SX line was just a 486 (later renamed the 486DX) where the FPU didn’t work.