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The more transistors a CPU has the faster it is right? We seem to keep trying to make the transistors smaller and smaller yet the size of the CPU remains the same, a few cm squared.

Why isn't the size of the chips ever doubled allowing twice as many tiny transistors on to the chip. Surely this would be a less expensive way to create a faster chip? Or will this create performance and/or manufacturing problems?

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I disagree that this question likely will solicit opinion because the reason for keeping the size of the die small is objective, and not a matter of preference. There are real reasons to do this. I have been exposed to this discussion at length, through my workplace, but unfortunately I can't post an answer due to it being closed. – sidran32 Aug 24 '11 at 0:58
@studiohack I forgot to @-reply here, so I'll do it now, so you get notified. Sorry if this is comment clutter but I can't edit my previous comment anymore. :) – sidran32 Aug 24 '11 at 1:37
This is a manufacturer's question, a question that concerns marketing and one that invites conjecture about why the industry is working the size issue as it is. @sid – random♦ Aug 24 '11 at 2:13
@sidran32: yes, random is correct, this post should remain closed because it is subjective and not constructive, it doesn't really have a clear definite answer. – studiohack♦ Aug 24 '11 at 2:20
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@studiohack It obviously must have a definite answer, else they would be bigger. I hate how on SE just one person can close a question based on their opinion whether its subjective or not. The answers below seem pretty clear definitive. – Jonathan. Aug 24 '11 at 8:36
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Well, the larger a single die is, the lower the yield of usable processors - ANY flaw would result in a useless or crippled chip.

Multi die processors are possible, but not cost effective - the pentium pro was THREE dies in a package, and had horrid yields.

I also believe heat dissipation would be affected - you'd need bigger heatsinks to dissipate the increased heat from the increased transistor counts.

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a long line from one transistor to another makes the switch time (and clock speed) slower

this is because the long line acts as a capacitor that needs to be charged above a certain level before the connected transistor switches

and many lines in parallel can interfere with each other on high frequencies (the main reason parallel connectors are disused)

and you can only dissipate so much heat with normal heatsinks (the reason why the processors are flat is to avoid heat buildup inside it)

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With the heatsink, laptops have very small heatsinks yet they do the job, how come desktop heatsinks are so much bigger, that they wouldn't be able to dissapate the heat from an oversized chip. With the distance between transistors, surely even just enlarging the chip by 2mm, would gain performance without a loss – Jonathan. Aug 25 '11 at 0:02
@jon laptops cpus are designed to keep power usage/heat generation low. desktops can afford to use more power however silicon (main component of a chip) can only transfer so much heat to the heat sink. So if there is a significant amount of it between transistor producing the heat and heatsink the cpu can overheat – ratchet freak Aug 25 '11 at 0:21
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