Asus n55sf random overheating issue

[Monsimeph]

Hi guys!

My wife's old yet still very capable laptop has been giving us hard time for the last couple of years. We tried to tackle this issue in the past but with little to no success.

About two years after its purchase it started randomly overheat. With randomly being the keyword. Most of the time it acts completely reasonable with idle temps of the CPU below 50C, But there are days when out of nowhere the temps start climbing to mid 60s and even reach 70C. The laptop comes with integrated GPU and Nvidia 555M card on top. IGPU can't stand any pressure at all and thermal throttles at 96C during gaming (very light gaming for the obvious reasons). Nvidia's card is a bit cooler but the driver crashes with TDR error as well around 85C.

In the hindsight we should have RMA'ed it when the issue came up for the first time, but we didn't. Due to previous experience with Asus tech service, which was exceptionally slow (took over a month to replace dead DVD drive) we just didn't want to do anything with it. So we called our friend laptop technician and asked him to check it out. He said there was too much thermal compound on the chip. He cleaned and re-pasted everything and it worked. For a week. Give or take. Then the craziness returned.

Now, it's a laptop. It's not new. So it overheats. I get it. The thing is, it's not consistent about it. It's been cool and well behaved for probably a few months and I heard no complains from the wife during this period. A couple of days ago the temps began freaking out again and the fans became noisy and annoying. The body is indeed hot, and hot air comes out of the exhaust vent, so I think bad sensors can be ruled out.

What we tried: updating windows, drivers, resetting bios, formatting, loading from live CD, system restore to 'cool' days, a cooling pad, fiddling with power options. Nothing. Doesn't matter whether it's on battery or not.
I can't put my finger on any sort of software related cause. However, it doesn't make sense to me that hardware problem will come and go as it pleases. Yesterday, for example, everything calmed down. By the evening when ambient temp dropped a little, the CPU was cold as ice with 39C. Today, while it's maybe 4-5 degrees hotter outside it's sitting on 65C as I am typing this post.

I suspect this is some sort of VRM problem, but I am not tech savvy enough to diagnose it properly. Any ideas what we can do to figure out the source of this annoyance? Is it worth to try and clean/re-paste again? Is it just bad laptop and we blew it by not RMAing it when we had the opportunity?

HWMonitor screenie just in case:

Spoiler

As always, your opining is very appreciated.
Thanks in advance!

 

[ModMonster]

Your CPU is fine. Its the GPU that's not good. 96C is REALLY high, but not that high for an older laptop. If you can try down clocking the GPU to decrease temperatures. Maybe the GPU needs new thermal paste or a heatsink/fan cleaning.

 

[Monsimeph]

It's integrated GPU that gets crazy hot so obviously it affects the CPU. I can't disable it because of the Nvidia Optimus horror - if only I could!

And no, it's not fine to have 70C degrees idle CPU. Especially if on some days it's much cooler than on others while ambient temps don't change much if at all. I know it's well within safe range, but even working on such a hot machine is unpleasant. If it stayed this way all the time, I wouldn't even bother. But since it can run much cooler I am wondering what can be done so it stays cool and doesn't start boiling randomly.

 

[Monsimeph]

Nothing?

 

[Wongeron]

Nothing?

I have the same Laptop series with the same specifications, when I first opened it, and note...REMOVED the whole cooling system, you will see that the GPU(video board) is separate to the CPU...yep, the N55SF has a removable/replaceable graphics card/chip(amazing huh? you can just make your own luck if you have a burned out video GPU to replace it from another N55SF spare parted one). The bit*hy part is that on this model you have to open the whole laptop up just to get to the whole cooling system itself. and when you reach it you actually see the separate heat sink going to the processor AND the actual GPU and this is why the whole thing knocks down your regular day techjunkies out there even in services(if you have the guts to do it yourself or have the opportunity see it for yourself if a person who opens it lets you sit by its side). This model thus being a actual hybrid between a multimedia one and a power one as well as a luxury/quality oriented product(this model had USB 3.0 and other tech stuff back when it came out when folks were only dreaming of, amazing tech) the heck the 3.0 was missing even in early 2014 models at a price, not to talk about sound tech(the portable woofer) and video quality. Therefor, when you open the actual product, you will see a specific thermal compound scattered all around especially on the GPU side, and after further analysis over the type of it I came to the conclusion that the actual factory compound used is the K5 Pro thermal compound, usually used on devices for example that require thermal pads(those being tablets, I phones, gaming consoles things that generate a lot of heat and need opening for cleaning very scarcely/rarely). And make sure you make a picture to see the manner of spreading of the compound as you open it up the manner being vital to the performance and heat dispersion, so if your average serviceman dogma placing a little pee size drop of thermal compound is usually OK in most cases, here you have to and you will see thermal compound being placed in higher quantity not only on the main GPU but on adjacent chips and components(remember to observe the photo I just told you to take before cleaning it up). The actual thermal compound and manner of spread and placing and proper cleaning will eventually offer a closer to the new bought period performance, of the product. Hope this helps and I am still satisfied by my piece of Asus jewelry of a model of N55SF

 

[Monsimeph]

Thanks for your lengthy reply Wonderon! I agree that the model is great and overall it's been an excellent machine ever since. As I mentioned, a friend of ours (experienced computer tech) opened and re-pasted everything a while back, however, it only helped for a week. I will definitely not be opening it on my own, But if another re-pasting could help, perhaps I can get someone do it for me.
May I ask what temps you're running at?
Thanks again!