7 Replies Latest reply on Aug 5, 2015 9:56 PM by rguevara

    i7 4790k temperatures fluctuation problem



      I put up together a new rig with i7-4790k and asus maximus vii hero onboard.



      During intel extreme tuning utility tests (measured by Real Temps) I see that my i7 have strange temperature fluctuations. It jumps constantly between 63-71*C. Each second there is gap between temperatures, for example 63->70, 71->65, 64->69 and so on. These gaps are in around 6-8 *C difference between each other.

      From the other hand when idle its stable 35-38 *C without any kind of fluctuation. I am using Dark Rock 3 cooling with push and pull config.

      ALso I am using 750 Corsair power supply. Uisng xmp ram profiles for 2400 MHz

      I haven't OC processor. It running 1.240 V at full load. I tried to lower voltages to 1.168 / 1.186 and temperatures fluctuation still occurs

      I changed paste twice already, dozing more or less paste. Cooling system is sitting right.

      It's bit strange for me, is that normal for Haswell to do so? Maybe there should be some options put to avoid that on motherboard?

      I would be glad for any help


        • 1. Re: i7 4790k temperatures fluctuation problem

          I don't think his i7-4790k is overheating. I think he was wondering if under load if it is normal for a CPU temperature to fluctuate unusually under load.


          The answer to that question, is yes it is normal for the temp reader to read CPU temps I did a test with my i7-4790k and running handbrake video encoding a video Big Buck bunny 4k 60fps  to ipod touch 460p 60fps constant I am getting anywhere from  56c to 62-63c temperature jump in 1 sec. All my cores are mid to to upper 50's and jump to mid 60's and upper 60's and back down to mid 50's. It feels like a huge gap, but because of load and the voltage temperature increase and decrease isn't linear. This is because of the aftermarket cooler being able to remove the heat quicker and the CPU speed changing from full load to almost full load.. According to http://www.hwinfo.com/ When rendering a video I am running anywhere from 4.4Ghz to 4.0Ghz, even 4.2Ghz constantly switching If you want to test a full consistent load, use cinebench or if it is to short use Wprime: Download | wPrime (run as administrator) run 1024 and it should take about 3 or so minutes to complete running all your cores at full load. Please don't use Prime95.. it does throw your cores to a hot temperature.. With Wprime you should see your temps go up and stay within 1 - 2c of each other because it is asking for full clock speed from all threads.




          PS I am using an aftermarket cooler myself because the stock cooler is below average in terms of keeping. I describe Intel stock cooler as a space heater plug into a dollar store extension cord.. It works but barely and not really safe.



          On another side note. The i7-4790k that my brother had was running 4.2 Ghz @ 4 cores with 1.250v...with stock cooler.. You can imagine it overheated... The first time I saw it my face almost hit the table.. The lowest I could get on his i7-4790k was 1.125v @ 4.2 Ghz.. Intel says 4.2Ghz should be good at 1.100v any lower and it blue screened. So I RMA and got another i7-4790k for him.. It runs better no doubt but I replace his stock cooler after it overheated again playing Battlefield 4 large map. The new CPU did run cooler and I was able to get lower voltage off of it. His CPU is now running 4.2 Ghz @ 1.070v.




          Intel stock voltages are way overestimated... When I put in his new CPU it tried to run stock voltages again at 1.200v+ @ 4.2Ghz... In his MSI bios I literately have his voltage offset by - 0.100 because that is how off Intel stock voltages are... that is right .1v offset because that is how off his was.. Mine is offset by 0.070 not as high as his but I am running a lower voltage then his.




          I have a Asus Z97-A and I attach some pics of my settings. I can do 4.2Ghz @ 1.056v stable 1.050v is mostly stable but will blue screen gaming for 2 hours. My brother can only do 4.2Ghz @ 1.070v so your mileage may vary.  Here are some pics from my settings.

          stock speed stock voltage.pngasus settings1.pngasus settings2.png

          • 2. Re: i7 4790k temperatures fluctuation problem

            Hi Simone

            Thank You for reply. Very usefull information for me. After quick thoughts I decided to RMA my i7 due to highter temperatures. With Realbench and Prime processor was hitting around 75 *C without any OC. I put in mind that I have Dark Rock3 cooling with push and pull fan config. Before that I was thinking to OC it a little bit but with that temperatures it's almost impossible to run in on manual voltages for longer time. I don't want to hit above 80*C even thought I have in mind that skylake comming in 1-2 years. I wish to use this stuff for atleast 4-5 years. I do hope that new part of i7 that will come to me in next week will be a bit better for OC purposes. Even without OC i shouldn't across70 *C on full load.


            Quick question Do You know really good cooling system that might work well with 4790k? I mean I have Fractal R5 case so it isnt a big deal to put any cooling system inside. Just it is not clear stated anywhere that else air or water cooling is better. From what I know water systems might finish off motherboard due to some sort of water leaks. Is it true?

            • 3. Re: i7 4790k temperatures fluctuation problem

              Hi, sorry for the late reply, Over clocking is all based on luck of the draw with the chips. At least that is what I have been reading online on what people are getting. Some can only get 4.6Ghz  and can't go higher no matter what voltage they throw at it. Others 5.0Ghz but with crazy voltage.. The first limit is the CPU design itself, what is the max multiplier it can run at, the next is what voltage can it run and is the voltage safe for long term. Finally is the temperature within a safe zone.


              Intel says the CPU is happy with a maximum of 74c for long term ARK | Intel® Core™ i7-4790K Processor (8M Cache, up to 4.40 GHz) under package specification. My aftermarket cooler isn't anything special it was $20 on Amazon. Under a full stress load, the worst I got was 72c with a 28c motherboard.


              The importance is the default voltage of your CPU. If the new one comes in, check to see what it is running at 4.2Ghz it should not be more then 1.100v if it is then you have to go to the bios and use offset and slowly turn it down until you get at least the CPU running at 4.2Ghz @ 1.100v then check the temps again. With your aftermarket cooler it should do the job.


              As for water leaks anything is possible but like anything it is probably very slim. Unless you plan to build your own custom water loop most of these off the shelf water cooler have everything sealed inside. Worst that can go wrong is the pump goes bad so it can't move water around. How To Spot a Dead CPU Water Cooler (My Asetek Water Pump Failed) - YouTube normally I guess what happens. The more extreme My $6500 Custom Watercooled PC LEAKED!!! Now lets fix it.... - YouTube more on the extreme side of someone customizing everything.


              For everyday off the shelf water cooler: Water Cooling Radiators as Fast As Possible - YouTube this guy gives a detail explanation.


              According to google most people just use the h100i as a default cooler for overclocking. If you want to install a bigger one for better heat absorption that is up to you. I came from a Pentium 4 to an i7-4790k so everything is fast for me...

              • 4. Re: i7 4790k temperatures fluctuation problem


                I am just woundering how to check what voltages i7 uses at 4.2GHz? Should I change something in bios? Kinda woundering is it something crusial about 4.2 Ghz speed. I'm asking this question because as I remember processor running idle voltages and on the load. it's 4.4 GHz at that point. Shouldn't I measure it on idle with basic 4.0 Ghz?

                I might got something wrong though

                Also I'm not that familiar how to put offset. Recently I tried to put manual speed but I guess it shorter processor lifespan , right?

                My motherboard it's Asus Maximus VII Hero rog z97.

                Correct me if I am getting something wrong, I'm still a begginer at this topic, OC stuff and all



                • 5. Re: i7 4790k temperatures fluctuation problem

                  The best way to over clock the processor is increasing the processor multiplier. I suggest you to use our Intel® Extreme Tuning Utility.
                  Intel® Download Center

                  It is not necessary to change manually the voltage and the offset.

                  Also, your Asus Maximus VII Hero rog z97 has its own tool to over clock the processor, It sets all the Cores at 4.4GHz, I recommend you to disable it.


                  Miguel C

                  • 6. Re: i7 4790k temperatures fluctuation problem

                    Hi Mike

                    Thanks for reply, I haven't install software tools for motherboard. It is something in bios settings that OC it automatically?


                    • 7. Re: i7 4790k temperatures fluctuation problem

                      Hi Greg87,


                      I am with Intel Customer Support and I cannot tell you about the tools that are available for your board because I don't know them, I know they are available and I would recommend that you check with Asus*.

                      On the other side, please check the following website: Intel® Extreme Tuning Utility (Intel® XTU) Supports Overclocking it has all details related to our Tuning tool.


                      I hope this helps,