I5-4670K Overclock question (4.2 Ghz at 1.10V)

JQuon126,

While IBT is good for stability testing, Prime95 Small FFT's is the standard for CPU thermal testing, because it's a steady-state 100% workload.

Prime95's default test, Blend, is a cyclic workload for testing memory stability, and Large FFT's combines CPU and memory tests. As such, Blend and Large FFT's both have cyclic workloads which are unsuitable for CPU thermal testing.

Other stability tests such as Linpack and Intel Burn Test have cycles that load all registers with all one's, which is equivalent to a 110% workload, and are also unsuitable for CPU thermal testing. The software utility OCCT runs elements of Linpack and Prime95.

Shown above from left to right: Small FFT's, Blend, Linpack and Intel Burn Test.

Note the steady-state thermal signatures of Small FFT's, which allows accurate measurements of Core temperatures.

Shown above from left to right: Small FFT's, Intel Extreme Tuning Utility CPU Test, and AIDA64 CPU Test.

The "Charts" in SpeedFan span 13 minutes, and show how each test creates different thermal signatures. Intel Extreme Tuning Utility is also a cyclic workload. Although AIDA64's CPU test is steady-state, the workload is insufficient.

Standard Ambient temperature is 22C, which is normal room temperature, and is the reference value for Intel’s Thermal Specifications.

Intel desktop processors have thermal sensors for each Core, plus a sensor for the entire processor, so a Quad Core has five sensors. Heat originates within the Cores where Digital sensors measure Core temperatures. A single Analog sensor under the Cores measures overall CPU temperature.

Core temperature is 5C higher than CPU temperature due to sensor location. Intel's Thermal Specification is "Tcase", which is CPU temperature, not Core Temperature. Tcase for your i5 4670K is 72C. Tcase + 5 makes the corresponding Core temperature 77C. These are your specs.

The relationship between Core temperature and CPU temperature is not in the Thermal Specifications; it's only found in a few engineering documents. In order to get a clear perspective of processor temperatures, it's important to understand the terminology and specifications, please read this Tom’s Sticky:

Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html

Please download Prime95 version 26.6 - http://windows-downloads-center.blogspot.com/2011/04/prime95-266.html

Do not run any version later than 26.6. The reason is explained in the Temperature Guide.

Run only Small FFT’s for 10 minutes.

Use only Real Temp to measure your Core temperatures, as it was designed specifically for Intel processors: Real Temp - http://www.techpowerup.com/downloads/2089/real-temp-3-70/

Also, what is your ambient temperature?

Thanks,

CT

(1) Ambient is "room" temperature, or more correctly, the temperature measured at your computer's air intake. Standard Ambient temperature is 22C, which is normal room temperature, and is the reference value for Intel’s Thermal Specifications.

Knowing your Ambient temperature is important because Ambient directly affects all computer temperatures. When performing a thermal test below or above 22C, remember to add or subtract the difference so that test results are corrected to Standard Ambient.

Use a trusted analog, digital or IR thermometer to measure Ambient temperature. If you don't have a thermometer, then just read the temperature from the thermostat / thermometer typically located in a hallway of most homes.

Here's the temperature conversions and a short scale:

Cx9/5+32=F ... or ... F-32/9x5=C ... or more simply ... an increase of 1C = an increase of 1.8F

30.0C = 86.0F Hot
29.0C = 84.2F
28.0C = 82.4F
27.0C = 80.6F
26.0C = 78.8F Warm
25.0C = 77.0F
24.0C = 75.2F
23.0C = 73.4F
22.0C = 71.6F Standard ... or ... 22.2C = 72.0F
21.0C = 69.8F
20.0C = 68.0F Cool

With conventional air or liquid cooling, no temperatures can be less than or equal to Ambient.

As Ambient temperature increases, thermal headroom and overclocking potential decreases.


(2) Keep in mind that we're thermal testing only.

My previous post described why we use only Prime95 Samll FFT's for a 10 minute thermal test, which is a steady-state 100% workload that gives us a valid benchmark for comparing Core temperatures to Intel's Thermal Specifications.

For stability testing, Prime95 Samll FFT's and Blend should be run for several hours. A combination of other stability tests, assorted apps or games should also be run for the appropriate number of passes or periods of time to verify stability.


(3) Adaptive mode is typically the best configuration, which is described quite thoroughly in this Overclocking Guide: 3 Step Guide to Overclock Your i7 / i5 Haswell Platform - http://www.overclockers.com/3step-guide-to-overclock-intel-haswell/

Sorry ... I was still editing my post when you answered. Please have another look at my previous post.

Download Intel Xtreme Utility to monitor your temps. Play a video game like bf4 or something cpu intensive. The Utility has a chart that monitors your temps in a graph and states the maximum/minimum feature.

It also has a stress test feature. This test is better suited for actual real world use. Programs like Intel Burn Test and Prime 95 put the cpu in extreme situations. They don't reflect real world usage and your temps will never even come close to that in real world usage. Especially gaming.

Your screenshot shows 10.7% load on Real Temp, so I can't evaluate your temperatures based on this information.

Please try again.

Let's not get ahead of ourselves.

Yes, you missed the point.

We need to know what your Core temperature are during the 10 minute test of Prime95 v26.6 Samll FFT's.

Your screenshot of Real Temp was taken at 10.7% workload, not 100% workload.

Yes.



Yes, but to give it a practical perspective, it should correspond with the maximum number of hours you actively sit and run your rig.



That's refreshing. I wish more Forum Members would take a more conservative approach to overclocking. Many are hell-bent to squeeze out that last 100MHz, and are willing to disregard the maximum recommended voltage and temperature at the expense of longevity.

It raises the question of when enough is enough, which suggests a word that's sorely missing in today's vocabulary ... "contentment".

Enjoy your rig!

CT