Why does my i5 4590 not stay at max boost for longer periods of time?

[CuriousMike]

I'm running an app that uses all four cores at 100% for about 40 minutes ( DeepSkyStacker, astro-photography software.)

I notice that my processor will only blip for a second at it's advertised max turbo speed of 3.7ghz -- it stays at 3.5ghz 90% of the time ( 1300/800/2800 etc the other time.)

What gives?

 

[Dufus]

3.7GHz (37x) is for when only one or two cores are active. When all 4 cores are active the limit is 35x (3.5GHz)

 

[CuriousMike]

3.7GHz (37x) is for when only one core is active. When all 4 cores are active the limit is 35x (3.5GHz)

Marketing doesn't make it sound like that.

Thanks for the explanation.

 

[Dufus]

Told you a fib there, 37x is when only 1 or 2 cores are active, 3 cores active 36x and 4 cores 35x.

 

[CuriousMike]

Is this the same methodology for all non-K chips?

i.e., max turbo-boost is governed by the number of cores active?

 

[Dufus]

Pretty much, there are some sites that will give the turbo stepping. For instance google wiki i7.

The i5-4590 has a base or guaranteed frequency of 3.3GHz (33x) and that is what TDP is based on. When running just 1 core instead of all 4 it's likely the CPU will be drawing less power. This can be taken advantage of by increasing the frequency and power draw of that one core while still remaining below the whole thermal design power (TDP) of the CPU. Hence the stepped frequencies wrt the number of active cores.

Yes, marketing wise it could be misleading without explanation.

 

[PG]

Cpu-world is the best site I know for this type of detail.

http://www.cpu-world.com/CPUs/Core_i5/Intel-Core i5-4590.html

3500 MHz (4 cores)
3600 MHz (3 cores)
3700 MHz (1 or 2 cores)

----

Maybe you already know this, but you can search by the cpu part number, or in the case of Intel, the S spec works too.
Every Intel cpu has an S spec code on it, and you can look it up that way.
In this case the i5-4590 is SR1QJ

 

[Erithan13]

There's definitely room for confusion with the way turbo boost works, and depending on how it's advertised it can be rather deceiving. The base frequency of your CPU is 3.3ghz which will often be quoted in the specifications but this makes it appear less powerful than it actually is. As long as the temperatures aren't too high when all 4 cores are loaded it will turbo up to 3.5ghz across all cores, giving a small boost compared to the base frequency performance.

The flipside to that is the 3.7ghz 'max turbo frequency' is only going to be seen on a single core at a time. So the specifications say '3.3-3.7ghz' while in reality you'll mostly see it locked to 3.5ghz under load.

 

[know of fence]

As long as the temperatures aren't too high when all 4 cores are loaded it will turbo up to 3.5ghz across all cores, giving a small boost compared to the base frequency performance.

I'm not so sure any more that temperature sensors are at all part of Turbo operation, seeing how especially mobile CPUs are TDP conrolled, which has to be an arithmetical Wattage average rather then a sensor.

Unless voltage is increased temperatures don't affect power consumption (leakage) in a way that is measurable with a common Watt-meter.

CPUs do auto-adjust voltage with load line calibration and perhaps other means, however I've actually never seen confirmation that a CPU selects a certain VID (auto core voltage) when 60 °C and a higher VID still when 80°C.

 

[Magic Carpet]

Hi Mike, what is your system? Did your mobo at any time support Multicore Enhancement of any sorts?

 

[Termie]

I'm not so sure any more that temperature sensors are at all part of Turbo operation, seeing how especially mobile CPUs are TDP conrolled, which has to be an arithmetical Wattage average rather then a sensor.

Unless voltage is increased temperatures don't affect power consumption (leakage) in a way that is measurable with a common Watt-meter.

CPUs do auto-adjust voltage with load line calibration and perhaps other means, however I've actually never seen confirmation that a CPU selects a certain VID (auto core voltage) when 60 °C and a higher VID still when 80°C.

Temperature does play a role, but only in extreme situations. All Intel desktop chips will drop to the minimum speed rating when they hit 100 °C. That's the only temp threshold.

By the way, as others have pointed out, there's nothing wrong with Intel's marketing here - it's not deceptive at all. The 4590 is rated at 3.3GHz. It will always run at that speed under load, if not higher. Turbo is just a temporary speed state, as the name implies. If you want a chip that will always run at 3.7GHz, you need to buy one rated at that.

 

[Zodiark1593]

Depending on the mobo, you can force the multiplier to run all four cores at maximum boost even under load. My own i5-4590 has the multiplier set to 37 across all cores, and all four cores maintain 3.7 GHz under continuous full load. This is with the stock cooler as well.

Do be aware if the igp is being used, pushing the max tdp may throttle down the cores anyway.

 

[CuriousMike]

Hi Mike, what is your system? Did your mobo at any time support Multicore Enhancement of any sorts?

Not at my machine atm, but it's an incredibly basic motherboard so I would guess not.

I'm happy with the CPU, not pissed at Intel, it's all good.

 

[Magic Carpet]

Not at my machine atm, but it's an incredibly basic motherboard so I would guess not.

Find out what it is and we shall check. You can have Turbo on all cores under certain circumstances.

My own i5-4590 has the multiplier set to 37 across all cores, and all four cores maintain 3.7 GHz under continuous full load.

Just curious, what is your board and bios version?

 

[Zodiark1593]

Find out what it is and we shall check. You can have Turbo on all cores under certain circumstances.


Just curious, what is your board and bios version?

Asus H97-Plus with w/e is the latest bios version right now.

 

[john3850]

On my 930,2500k and my 3770k I can just disable C1E to get all the cores to the same maximum speed.
I use RealTemp to disable the C1E setting from the desktop.

 

[CuriousMike]

Find out what it is and we shall check. You can have Turbo on all cores under certain circumstances.

OK, according to CPUID HWMonitor, my motherboard is a MSI H81M-E33 V2 (MS-7846)