Thursday, March 5, 2015

performance - What makes a computer slow?


Why does it take so long to start up a computer or run an application? What's the bottleneck? How can we improve it?




Well, I mean, what takes so much time to boot, or run an application?


So far, I got a pretty good answer:


1.The Hard disk is too slow.


Anything else?


Answer



Today, the bottleneck is the harddisk. The main memory is about 10-1'000 times slower than the internal caches of the CPU. The harddisk currently is about 1'000 to 1'000'000 times slower than that. On the negative side, applications get bigger all the time (more fancy icons, more functionality), take more memory (so you need to swap to disk -> slow).


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