The death of CPU scaling: From one core to many — and why we’re still stuck

This is the first time I have heard of this: Dennard Scaling.

Dennard scaling. Dennard predicted that oxide thickness, transistor length, and transistor width could all be scaled by a constant factor. Dennard scaling is what gave Moore’s law its teeth; it’s the reason the general-purpose microprocessor was able to overtake and dominate other types of computers.

Interesting Stat of speed improvments comparing periods of time:

From 2007 to 2011, maximum CPU clock speed (with Turbo Mode enabled) rose from 2.93GHz to 3.9GHz, an increase of 33%. From 1994 to 1998, CPU clock speeds rose by 300%.

Sorry this is a long one. This statement really talks volumes on how one chip that can do 40-400ghz is far supiorior to a 110multi core chip (say 110 core/3.0 = 330ghz) "current MIT research breakthrough"

or the past seven years, Intel and AMD have emphasized multi-core CPUs as the answer to scaling system performance, but there are multiple reasons to think the trend towards rising core counts is largely over. First and foremost, there’s the fact that adding more CPU cores never results in perfect scaling. In any parallelized program, performance is ultimately limited by the amount of serial code (code that can only be executed on one processor). This is known as Amdahl’s law. Other factors, such as the difficulty of maintaining concurrency across a large number of cores, also limit the practical scaling of multi-core solutions.

AMD’s Bulldozer is a further example of how bolting more cores together can result in a slower end product.

Holly cow this is allot of power use: Ref page3

Intel’s CPUs top out at 140W TDP; Nvidia’s upper-range GPUs are in the 250W range.

Dark Silicon:

The fact that transistor density continues to scale while power consumption and clock speed do not has given rise to a new term: dark silicon. It refers to the percentage of silicon on a processor that can’t be powered up simultaneously without breaching the chip’s TDP.

THIS ONE GETS ME HORNY!

Regardless of chip organization and topology, multicore scaling is power limited to a degree not widely appreciated by the computing community… Given the low performance returns… adding more cores will not provide sufficient benefit to justify continued process scaling. Given the time-frame of this problem and its scale, radical or even incremental ideas simply cannot be developed along typical academic research and industry product cycles… A new driver of transistor utility must be found, or the economics of process scaling will break and Moore’s Law will end well before we hit final manufacturing limits