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what do nanometers say about CPUs

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March 15, 2013 10:30:01 AM

I have a question about what do nanometers do in CPUs. I really have no idea since its far from be 22 nm in any direction. Its probably something with interior but I really dont know. I heard that Intel is making new 14nm CPU and I want to know how much does that help in gaming. ANY help is wellcome.

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March 15, 2013 10:43:43 AM

The "process size" in namometers measures the width of the individual transistor elements in the CPU. Modern Electronic components are made from huge numbers (into the billions on high-end parts) of transistors wired onto silicon chips. Shrinking the individual circuits allows a similar chip to be made smaller and to consume less power, or for a more complex chip with more transistors (and more computing power) to be built in a similar size and power envelope.

Intel is the world leader in shrinking transistors, a major reason for their dominance.
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March 15, 2013 10:54:47 AM

In a nutshell, nm basically refers to the physical size of the CPU. Specifically it has to do with the size of the transistors. The smaller the size of the transistor (nm), the smaller the overall CPU is. By itself, it has nothing to do with performance.

The smaller size allows for lower cost of production because more chips can be manufactured on a single silicone wafer. It also means lower power consumption and less heat is produced. Indirectly, this means that the clockspeed can be increased as long as the amount of power consumed does not burnt out the circuitry and the amount of heat does not damage the CPU.

Theoretically speaking, an Intel Ivy Bridge i5-3570k built using 22nm and 140nm die process will perform the same as long as both CPUs get enough power and the heat generated efficiently. Of course an Ivy Bridge CPU built using the 140nm die process would be massive. Assuming a i5-3570k using the 22nm die process is 1" x 1", if it were built using older 140nm tech, then it would be around 6" x 6" in size.

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March 15, 2013 10:59:35 AM
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Funny you should ask. I actually am an integrated circuit designer and am designing in 28nm right now. However, I do analog design, that is, amplifiers and bias circuits and PLL's etc. not computers.

22nm means twenty-two billionths of a meter, or just under a millionth of an inch. That is the gate length of the CMOS FET's, or transistors in the chip. To simplify things, the gate length is the distance between the two contacts in the logic switches. The lower that distance is, the smaller, faster, and lower the power of the logic switches are and hence, the faster and lower power the processor is. 14nm, or a bit more than one two millionth's of an inch.

Now how this will effect gaming is a whole other question. The subject is very complex and involves quantum mechanics and all, but, basically, making transistors smaller and smaller is getting harder and harder. The cost is rising, and the benefits are shrinking. Way back in the 80's when we went from , say, 2um to 1um (two millionth's of a meter to one millionth's of a meter), the area of the chip was more than halved, and the performance was doubled, at least. Now, because we are hitting the limits, those gates are only a couple dozen atoms long now, weird stuff happens and you no longer get the response you want. One advantage for sure is lower power.

To boil this down. 14nm will be lower power and faster, but not a whole lot like the good old days. For most games around now, this extra processor power won't be needed. However, some new games, like Crysis 3, really requires a lot of processor power. So, by the time we see Broadwell, summer2014 or later. Perhaps many games will need extra processing power. Keep in mind though, Intel seems to be going after lower power, rather than greater processing power.
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March 15, 2013 11:17:49 AM

jaguarskx said:
In a nutshell, nm basically refers to the physical size of the CPU. Specifically it has to do with the size of the transistors. The smaller the size of the transistor (nm), the smaller the overall CPU is. By itself, it has nothing to do with performance.

The smaller size allows for lower cost of production because more chips can be manufactured on a single silicone wafer. It also means lower power consumption and less heat is produced. Indirectly, this means that the clockspeed can be increased as long as the amount of power consumed does not burnt out the circuitry and the amount of heat does not damage the CPU.

Theoretically speaking, an Intel Ivy Bridge i5-3570k built using 22nm and 140nm die process will perform the same as long as both CPUs get enough power and the heat generated efficiently. Of course an Ivy Bridge CPU built using the 140nm die process would be massive. Assuming a i5-3570k using the 22nm die process is 1" x 1", if it were built using older 140nm tech, then it would be around 6" x 6" in size.


Well, as a professional integrated circuit designer that has designed 14GHz counters in 28nm CMOS you are wrong on many counts. That doesn't mean much, for this stuff is exceedingly complex and you need a degree in engineering to begin to understand this stuff.

Until we got to, say, 90nm or so, each step down in size made the transistors much faster. The basic speed of a FET is it's gain divided by its capacitance. As they got smaller, the gain went up and the capacitance went down so halving the size would make it up to 4 times faster (doubled gain and halved capacitance). But as we approach quantum mechanics effects, this is no longer true, For instance, 28nm is only marginally faster than 40nm when you just look at the transisters themselves.

Another factor in speed, and a dominate one in small feature lengths, like 22nm, is the size of the circuit. For the longer the traces connecting the transistors are, the slower they are. This is due to the parasitic inductance, resistance, and capacitance of the traces. You simply cannot make a 140nm CMOS process run a 4GHz. It is physically impossible. Any given circuit in 140nm will be nearly 100 times larger than it would be in 14nm. The parasitics would kill you. Not to mention, the fact that 140nm transistors are slow and have low gain. If this was possible, don't you think it would have been done years ago? Another factor is simply the speed of the signals on the traces. They travel at about 60 to 80 percent of the speed of light. With large dies this is a factor too. Not to mention transmission line effects, reflections etc.
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March 15, 2013 12:08:59 PM

babernet. That's great explanation. Is "Hot carrier damage" also a parasitic effect?
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March 15, 2013 12:26:44 PM

satyamdubey said:
babernet. That's great explanation. Is "Hot carrier damage" also a parasitic effect?


Interesting question. No, hot carrier damage is actually a quantum mechanics effect where an energized electron punches through the channel and destroys a tiny bit of it. This is caused by putting too much voltage across the transistors. It causes a gradual degrading of the transistor's gain. This is what happens when we overvolt processors.
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March 15, 2013 12:50:27 PM

okay, I re read your post on parasitics and think I get it a bit. It's some what similar to power losses on long transmission lines due to line mutual inductance and capacitance. thanks a lot :) 
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