How can the system be bumped-up to the next evolution of RAM-processing..?

Marko Vojinovic vvmarko at gmail.com
Wed Nov 2 03:08:44 UTC 2011


On Wednesday 02 November 2011 01:56:13 Linda McLeod wrote:
[snip]
> Why is there RAM..?  Why can't the OS
> run its RAM off'n the hd..?

RAM exists because I/O of a HD is waaay too slow. You can get a feeling just 
how slow it can get when you open too many apps simultaneously, thus 
exhausting available RAM and making the OS use the swap partition for extra 
memory. It's *painfully* slow, the machine becomes practically unusable, and 
it's a complete waste of cycles of today's fast processors.

Even the I/O of RAM itself is fairly slow compared to the typical modern 
processor. That's why processors now have a built-in cache (which is basically 
a smaller amount of RAM on the processor chip itself), in order to speed up 
execution of programs and calculations.

You might then ask "why the processor designers don't put all RAM on the 
chip?" Because it would be too big, geometrically. In order to make the 
processor work on a 2GHz frequency or such, the chip surface must be small 
enough to keep everything in working conditions. Otherwise you run into out-
of-sync problems, uneven heat and voltage distribution problems, and all sorts 
of stuff that would make the processor fail. So the bulk of RAM must be 
separated, on their own chips, and communitace with the processor via the 
motherboard, which is again quite slow, due to its size and other reasons.

HTH, :-)
Marko



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