What is CPU Throttling and How Do I Identify It?

[InteXX]

Hello from Alaska

A contributor to my thread over at ServerFault suggested that I look into CPU throttling. Specifically, random down-throttling.

As this is the first I've heard of the concept, I'm investigating. Given the problem at hand (see the link above), what is it, what's the best way to monitor for it (long-term) and how would I recognize it if indeed it is occurring?

I've gotten as far as finding CPU-Z, but this appears to be only a short-term ad hoc monitoring tool. I need to set up some sort of logging that can last as long as a two week session.

Thanks,
Jeff Bowman
Fairbanks, Alaska

 

[mrmez]

Throttling is where the CPU gets too hot, and reduces it's speed to keep cool.

Not sure of anything that can log that long, but Speedfan can be good.
http://www.almico.com/speedfan.php

 

[InteXX]

Throttling is where the CPU gets too hot, and reduces it's speed to keep cool.

Not sure of anything that can log that long, but Speedfan can be good.
http://www.almico.com/speedfan.php

Thanks. I'll look closer at SpeedFan.

 

[InteXX]

Throttling is where the CPU gets too hot, and reduces it's speed to keep cool.

Not sure of anything that can log that long, but Speedfan can be good.
http://www.almico.com/speedfan.php

Is this CPU speed that you refer to the same info as what's available via WMI?

Thanks,
Jeff Bowman
Fairbanks, Alaska

 

[mrmez]

Seems like you are taking a pretty complicated look at something thats quite basic, but lets take a look...

If you look at my signature, my CPU runs at 3.0Ghz. In my case, being an older CPU, it runs at 334Mhz FSB (front side bus), with a x9 multiplier. 334x9 = ~3,000Mhz or 3.0Ghz. This is known as your 'clock rate' and can be made up of varying FSB's and multipliers.

It's the most common number used to determine 'speed', but theres more...

From there, you have CPU cores. You can think of it as a separate CPU, but on the same physical package. 4-6 cores are pretty standard these days.
In my case, there are 4 cores, each running at 3.0Ghz.

Lastly there is the CPU instruction set.
While your Ghz lets you know how many CYCLES a second the cpu can perform, your instruction set determines how many and what instructions can be performed per cycle.

So... cycles aint cycles.
Think of it as traffic or transporting stuff.
Whats better, transporting goods at 80, or 100?
100, right?
100 with a car load, or 80 with a truck load?

It's why an Intel Core i3-4130 @ 3.2Ghz and only 2 cores is still faster (for gaming at least) than an Athlon X4 750K @3.4Ghz and 4 cores.
The Intel CPU also uses ~half the power, comes with integrated gfx, but it does cost more.

A combination of clock rate, cores and basically the generation (or year) of the cpu will be a good guid as to how fast it is.
Like anything tho, it's all relative and you do need to know what is what.