CPU running very hot! Did I make a mistake?

[jebus_beler]

I recently posted about a system I intended to and then finally built:

Code: Select all

Case:  Sharkoon CA-I                      
CPU:  Intel Core i7 4790K - 4 GHz        
Cooler: Scythe Kozuti SCSK-1100	        	 
GPU:  GF GV-N970IXOC-4GD                 
Mobo:  Asus Z97E-ITX/ac                   
RAM: Kingston HX318C10FBK2/16  (16gb)   
HD: Samsung/Seagate   ST1000LM024 Momentus Spinpoint M8
PSU:  Silverstone SST-ST45SF-G 

The idea of the system was to have a very small portable and powerful system and it really seemed to fit the bill -- it only weights 4.34 kg! I wanted it to be quiet but it wasn't the main priority (portability and power were the main priorities, in that order). My main use is numerical work and I plan to have it running for days on end.

After building I started using it and noticed that on full CPU use the core temps would get really high -- starting at 70 and going quickly up to 80 then 90 then back down again. The scythe's fan would rev up to 3200+ and the case's outtake fan would also rev up. When idling the cores are between 35-40 C and the fan is at 2800. My other much larger desktop only gets to 60C at full load (with an i7 2600k) but I thought that might just be due to it have a much larger cooler (scythe mugen).

At first I thought the high temps were just an unfortunate side effect of a small case and was gonna post here asking for advice on how to improve things but googling around a ltitle I see that these temps might be alarmingly high. So my first question: should I be worried? I actually (stupidly) left this running overnight to check how it would do and it seemed fine the next morning but I've seen various posts saying to switch off your computer the moment the temps get so high. In any case its off now!

Just to be clear -- I am _not_ overclocking or doing anything like that.

In hindsight I remember when I built it that the scythe's fins touched the top of the ram and now I'm wondering if perhaps this stopped it from actually pushing down enough and making contact with the CPU. I did appy thermal grease and it seemed to connect well but there's no way to really tell. Could this be the problem?

I also have a Noctua NH-L9i that I had ordered (to decide between it and the scythe) and was gonna send back but now I'm thinking maybe I should try it since it won't have the same issue of bumping into the ram. But disassembling the whole thing is a huge pain so I wanted to get some feedback before going down that painful path.

I also should clarify that the case is definitely not crowded. Although its small the sharkoon is rated for an ATX power supply and a ~10cm cpu cooler. Since I got a smaller cooler and an SFF supply there's plenty of space for air flow (which is why the temps surprised me so much). My motivation for not getting a larger cooler was that I want to be able to travel with the case and I worried a heavier cooler would damage the motherboard if the box is bounced around.

Any thoughts, suggestions, would very much appreciated as I'm suddenly a bit morose about this whole thing

[washu]

Both the Scythe Kozuti and the Noctua NH-L9i are meant for 65W max CPUs. The i7-4790K is pretty much the hottest 1150 CPU at stock, those small coolers simply wont cut it. You will have to get something bigger to cool that CPU.

The thermal protection on Intel CPUs is pretty good, so you are unlikely to permanently damage it. You are seeing the CPU overheat, throttle and then repeat the cycle.

[jebus_beler]

Both the Scythe Kozuti and the Noctua NH-L9i are meant for 65W max CPUs. The i7-4790K is pretty much the hottest 1150 CPU at stock, those small coolers simply wont cut it. You will have to get something bigger to cool that CPU.

Thanks for the reply!

I have the stock cooler which I guess I could probably use but I somehow always thought that was inferior to aftermarket coolers but clearly it should be rated to handle this CPU.

Would the big shuriken be a good alternative or will it likely also interfere with the RAM? I have a much lower powered machine with a shuriken which I could switch with the kozuti.

I'm really a little confused though...looking at the kozuti and the stock cooler its hard to imagine that the stock cooler can really do so much better a job. The kozuti is comparably sized and it has a very high fan speed so how could it possibly be worse? Actually I just checked and it looks like the Kozuti can handle a TDP of 95W (whereas I think the 4790k is 88 TDP) but its only "quiet" for a 65 TDP processor:

http://www.quietpc.com/kozuti

Is it not more likely that the heat sink is not well connected?

Btw is there any way to test if I've damanged the CPU -- I guess the fact that it never shut down should indicate that it throttled itself appropriately?

[Abula]

The i7 4790K is very fast but also runs hot, im technically not overclocking, well kinda.... my motherboard allows the full turbo on 4 cores, so i run at 4.4ghz, but at this on prime.... i reach 90C+ on 800K test... i drop it to 4.2ghz and i dont reach 90s, more like mid to low 80s under prime95, under normal conditions i never even hit 70C, its mostly on stress tests, either way, there is no escape from the CPU getting hot if you are running it at past 4ghz under stock voltages.

[jebus_beler]

The i7 4790K is very fast but also runs hot, im technically not overclocking, well kinda.... my motherboard allows the full turbo on 4 cores, so i run at 4.4ghz, but at this on prime.... i reach 90C+ on 800K test... i drop it to 4.2ghz and i dont reach 90s, more like mid to low 80s under prime95, under normal conditions i never even hit 70C, its mostly on stress tests, either way, there is no escape from the CPU getting hot if you are running it at past 4ghz under stock voltages.

Thanks for the reply.

I'm not doing any manual overclocking but like you its possible my motherboard is letting it run at 4.4Ghz with all 4 cores. I can check that and maybe disable it. Do you think that might keep the temps down to a saner level?

I want to emphasize that in my case this is not synthetic stress testing...I set this up as a "compute" machine so it will be running 24/7 for a few days on end doing some numerical work (unless I switch to the GPU). So its more important for me that its stable and sustainable...a 10% performance hit (down to 4 Ghz) is not a big deal by comparison. Can anyone suggest what a safe temperature in this kind of scenario would be (for 24/7 usage)?

Btw abdula, is this with the Thermalright Silver Arrow IBE? That seems like a very serious cooler so if you can't keep the temps below 90C I very much doubt I can with my smaller case.

Is the 4770k supposed to be cooler? I could always try to send this back and get the 4770k (I opted for the 4790k because of the higher default speed).

[Abula]

Btw abdula, is this with the Thermalright Silver Arrow IBE? That seems like a very serious cooler so if you can't keep the temps below 90C I very much doubt I can with my smaller case.

Yea its tough to keep the 4790 under control, but this is motstly because of the stock voltages/clocks, no intel CPU has even been ran so high, 4.4GHZ is a very high clock for a haswell cpu, not many 4770K reach it, and this is a guarantee with the 4790K.

Is the 4770k supposed to be cooler? I could always try to send this back and get the 4770k (I opted for the 4790k because of the higher default speed).

No the 4770K is suppose to run hotter, it suppose to have worst termal paste than the 4790K. I also own a 4770K, under the same voltages and clocks the 4790K runs like 4C lower. Still my 4790K run hotter but with higher clocks =P

In my experience the temp skyrockets past 4.0ghz, below that its pretty much very easy to cool, you can try underclocking a bit, the 4770K comes stock 3.6ghz base 3.9ghz turbo, with this clocks your cpu should run a lot cooler, but you also nerfing it some.... but really the CPU can handle almost everything i throw at it, i don't need the full 4.4ghz atm.... its up to you to test and see what works for your setup, but i would recommend you keep the 4790K, its a superb cpu if you use the hyperthreading.

[jebus_beler]

Abdul, can I ask how hot your CPU runs at idle? I think mine starts aronud 35 but then climbs up to 35-40 (varied over cores and time). I guess at idle it should be running at 4 Ghz not 4.4 so should be a good comparison (to check if I've done something wrong installing the heat sink).

Btw have you seen threads like these claiming that this is really an issue with some 4790's:

https://communities.intel.com/thread/54 ... 0&tstart=0

I might also try some of the suggestions in that thread to see if i can keep the temps down.

[Abula]

Abdul, can I ask how hot your CPU runs at idle? I think mine starts aronud 35 but then climbs up to 35-40 (varied over cores and time). I guess at idle it should be running at 4 Ghz not 4.4 so should be a good comparison (to check if I've done something wrong installing the heat sink)

Mine idles 25C or around, but thats pure idle, light load like opening webpages can make it jump to 35C easily, and with light load i reach close to 50C, gaming around 55-60C, all those temps is with 20C ambient.

Now I do allow my CPU to downclock on windows, mine goes down to 800mhz like most haswell cpus, this helps keep the idle temps very low and the clocks go up to 4.2ghz (in my setup) depending on the load.

Btw have you seen threads like these claiming that this is really an issue with some 4790's:

https://communities.intel.com/thread/54 ... 0&tstart=0

I might also try some of the suggestions in that thread to see if i can keep the temps down.

TBH i didnt put too much into searching about the 4790K, its a great CPU, it has better termals than the 4770K, but still the way its design, you wont get Sandy Bridge temps ever.... but at the same time i never see it pass 65C on my usual tasks... so i dont really care much, for me its fine as it is.

[CA_Steve]

Too much CPU for either of these coolers or the box cooler.