i7-940xm high temp on only one core?

Hey guys I am slowly learning things from these boards and now have another question to throw out there hopeing someone can shead some light on my issue.

I have installed a 940xm in my r2 and I have found out they run a lot hotter than the 720qm I originally had.

I have repasted the cpu with AS5 and am getting ready to play around with the screw tension to get good contact.

However my limited knowledge leads to this question, in hwinfo I can see the 4 temps of the cores.....

max temp
core0 95c
core1 83c
core2 85c
core3 83c

why is the first one 10c hotter than the other 3, I would have thought they would all be close together????

 

are you using a software like prime95 or wPrime in order to load evenly all cores?.

If yes, or the paste hasn't applied evenly on the core, or the core doesn't lie evenly seated.

After repaste, start the laptop with the keyboard connected (or it wont start up) but removed in order to have access to the cpu screws. while running wprime or prime95 with load on 8 thread, adjust the screws in order to have even temperatures across the 4 cores. Apply the thermal paste as a layer, don't let it spread by it self.

 

no man I dont have either of those programs....the only thing I have done with this cpu is use the 5% overclock in the bios.......should I use one of those programs to get better core usage and even temps?

 

if you were not stressing your cpu on all of his cores, than maybe some application is using just a single core. Even so, your temperatures shouldn't be that high on normal usage.

I would sugest you to repaste your cpu, then download either wprime or prime95 (google them, you'll find'em without problem). once you have either of this 2 software, just run them and set them in order to use 8 thread and so fully load your cpu. My guess is that with the temperature you are having right now without pushing your cpu, you shall expect temps to skyrocket unless you do a repaste.

Use one of the above softwares to stress your cpu while adjusting the screws, so you will know exactly how good or bad you are doing it.

 

sorry man I should have mentioned that those temps were under pretty much full load playing BF3 for a while.

But I will have a look into these programs you mentioned as these temps are not ideal even under load.

 

it probably because part of the CPU die isn't making good contact with the heatsink or is lacking some thermal paste on one side.

I would do a repaste and reseat the heatsink. I'm willing to bet that it evens out the temps.

Also keep an eye on the heatsink...it could be slightly warped

 

That 95°C is too high for any game. You need to do a repaste regardless. You paid good money for that hardware, and you don't want it cooking like that my friend.

 

This is kind of happening to me after trying to paste job in two different methods of two blob in the middle and full spread

there is temperature difference between adjacent cores that can be somewhere from 7-10c under full load with prime 95. this causes throttling when using throttlestop as a core or two would reach the 95 degree mark.

I am assuming that at this point it maybe just these two cores running hot or something wrong with the temperature sensor. Because the two different method of paste job is literally ending in the same result of these same two cores behaving wierdly...

I have mine oced to 25, 25, 26, 26 with default voltage. it is OEM chip.

Any ideas what I can do?

 

I have the same problem, my cores 0 and 1 are consistently 10 C higher than the other 2 cores. Playing Skyrim, I usually see temps in the high 80's on cores 0, and 1.

I took it all apart and monitoring the temps fiddled with the screws without success.

Ideas?

 

ur 0 and 1 core may be high if the game utilizes those cores more than others. perhaps just with the task manager performance tab to see if this is the case.

if not, then try repasting or something. it might be that the left side of the processor is not well intact, hence your 0 and 1 cores having high temp.

I think mine seriously is something wrong with the sensors, since it is 0 and 2 cores that run high, hence eliminating the possibility of bad repasting. not to mention that i tried three times with different methods but same situation.

also when in idle or very light use of 20% or so, i can often see the hot cores having temperature difference of 10c in split second. literally it would be like 82c in one second and 70c in the next second. I highly doubt that 10c difference can occur in split second when the cpu usage is low and very consistent within same cores.

I can try to ask for a new heat sink, but not sure if that will make the difference.... I cant believe that OEM chips can be this unreliable!

 

If you messing with the screws you need to make sure to have an even load on all cores. I use wprime 1024 with a full 8 thread load.

 

Running prime 95 on full load gives equal load on all cores right?

The temp different is still quite large in this scenario. Before I can really blame the sensor, I would like to try something else...

Anyone got ideas?

 

Bro, repaste and reseat your heatsink. A slightly warped heatsink with bad contact on one side or too much/not enough paste on one side will cause these issues

 

I tried repasting three times each with different method.

the problem with my cpu is that, it isnt one side of cpu being hot, but rather like this:

cpu0: HOT
cpu1: Not hot
cpu2: HOT
cpu3: Not hot.

the heat sink could be warped, but shouldnt that result in one side of the cpu being hot? like cpu 0 and 1 being hot and cpu 2 and 3 being not hot.

The result was for all three methods. I used AC5 btw

 

interesting...that isn't something that you normally see. Next time you pull off the heatsink. Examine it for any imperfections on the copper plate. Could be wavy. Or could be the CPU itself in which case, there is nothing to do.

Check your CPU die for any imperfections too

 

it is beacause cure#1 is used more. But repaste. I think you have put too much of thermal paste.

 

I will check the heat sink. I do remember that when I repasted and took the heat sink off, I did see a pattern on the heat sink, which showed how some part was well stuck to the cpu and while others did not. if you know what i mean..

The temp was found when running prime 95, so all cores were running at the same level. I tried with little and a lot of paste with diff method. they all have the same result...

 

you can also try another paste. I've found that AS5 sometimes gets, for lack of a better term, watery. Could lead to high temps

 

Then maybe check if radiator grill isn't clugged?

 

what would you recommend? AC5 has served me very well since the core2quads till sandy bridges and multiple gpus..

Could it actually be the case where the cores or the temp sensor is slightly defective?? I thought the cpu was the most reliable part of a laptop...

everything is 100% clean. DId anyone have actual experience with defective heat sink though?

 

I love Prolima-tech PK-1. This is the best paste currently available (Dec 2011). I also like MX-4 and OCZ Freeze. The common denominator of all these is that they are easy to work with and have outstanding temps when there is only moderate contact. Seeing how you might be experiencing moderate contact between your heatsink and cpu die, you want to get a paste that does well in this arena. AS5 only works well when there is perfect contact between heatsink and cpu die

HERE: look at moderate contact for what you might expect in a laptop

2011 Thermal Compound Roundup – Results Compilation | Skinnee Labs

Anything is possible bro. I've seen desktop CPUs where there is nasty contact between the cpu die and the metal lid. There is nothing you can do in this situation. Mobile cpu's are lidless though, so you see the die right away. You can't control what's under that die

 

For sure I will have to check these out. I have been thinking that AC5 is always one of the best. But did not realize how imperfect heat sink can result in this...

Besides the new pastes, any other way I can resolve the issue? One one or two cores run too high, it results in cpu throttling, so I would really like to fix the issue.. thank you for your help so far!

 

Dellien, reset everything to stock, run Prime95 8 worker mixed test (default) for 10 minutes. You can monitor with something like HWINFO64 or whatever temp tool you prefer

What are your temps across the cores?

 

first of all, the first core reaches 95 degrees very fast so it throttles little bit. please keep in mind that i have it oc with throttlestop

core 0:87
core 1:80
core 2:84
core 3:80

The temperature above is not 100% accurate as the temps change spontaneously within a few-degree margin due to cycle of throttling and fulll speed.

but right before it throttles, the core 0 can reach 95.. right now with the above temp, the cpu is running at 930Mhz..... things are getting too hot, too fast.. Even when the cpu is running at 930mhz, core 0 runs at 87 degrees... throttle stop does not stop this throttling.

Resetting everything has the same result.

after using prime 95 after having been at normal use, it will throttle in literally 15 seconds with or without throttlestop. it is just running too damn hot!!

what do you think is wrong?

 

don't know bro. But in the meantime, keep the back of the laptop propped up without obstructing your intakes underneath. This will drop your temps 5-7c

if you're confident that your paste job is decent...maybe a bad heatpipe? I've seen that before too

It worries me that you are getting those 95c spikes though. Is the CPU under warranty?

 

I just had it propped up using my calendar and thank god the fans are no long as noisy... Yes the cpu is still under warranty. But not sure how I will have to ask them to replace it...

could this be the very unfortunate one of the 0.01% of defective cpus? urggggg.... would there be a better chance of my just having a bad heat sink?

I can live with the 3rd core being slightly hotter than its adjacent ones, but the core 0 is DEFINITELY wayyy hotter than others, seeing when running prime95. I mean it could be heatsink problem, but still not sure..

it is oced to 25,25,26,26 without voltage increase. do you think perhaps increasing voltage by 75mv will help? it could be running hot or misbehaving due to lack of power... i understand that it should theoratically increase more voltage, but yeah..

 

I've seen very interesting CPu temps like yours when there is a blockage in one of the heatpipes on the heatsink. That's also possible. Seeing how a CPU defect is very rare, especially on XM processors (because those are at the top of the binning process), i'm more inclined to think its a warped heatsink, bad heatpipe, bad paste and/or paste job etc

increasing voltage will only make it hotter. Don't see how that can help

I think if you are underwarranty, you should call dell and see if they will send someone. The tech will come with a new heatsink/fan, paste, and a cpu. They will try it all till it runs good

 

Thank you for your help again.

When I get back, I will try to get a new heat sink. There is only one kind btw for all cpu types for the R2 right?

 

my pleasure dude!

The heatsink for R2 is like this one

Upper Edge Tech - Dell OEM Alienware M17X R2 CPU Heatsink RVXVK Warranty Same Day Shipping

 

Yup that is the one that I have.

Meanwhile, I will try with those pastes first. Is amazon the cheapest place to get them?

 

Or this one Dell Alienware M17X Alienware-R2 CPU Heatsink RVXVK | eBay
I believe it is cpu... or paste