Lessons from buying, breaking, and fixing my laptop PC.

My laptop is an ASUS K501-UX, I have mixed feelings about the machine. They are nice for battery life considering its processing power. I have attached images of my rework on the unit below.

My model shipped with:

• 6th generation (Skylake) dual core i7 6500u CPU
•  8GB DDR3 RAM, Nvidia GTX 950m GPU
•  128 GB m.2 SATA SSD
•  1TB SATA mechanical hard drive

I imaged the SSD onto an external to preserve factory settings before installing Linux Mint on the first day I had it, I have used the Windows drive for a while and although Windows 10 is much better than previous versions I still prefer Linux Mint for several reasons ranging from software architecture to my preferred look and feel.

The modifications I made to the machine are as follows:

• Replaced the mechanical hard drive with a Samsung 850 EVO 500GB SATA based SSD
• Upgraded the thermal paste (I'll explain later)
• Soldered the smaller fan to the main board
• Fixed the audio chips after solder exploded onto them

Replacing the hard drive and installing Linux onto it was my best decision with this machine, I used the new SSD as my Linux boot disk so I can easily put Windows back onto the smaller SSD if I so choose as I still have the disk image floating around my collection of hard drives. The Samsung SSD I installed is fast and saturates the SATA bus it's connected to allowing real world performance in the order of 450 to 499 MB read per second, not overly impressive compared to an NVMe SSD pulling more than 3 gigabytes per second read speed but the limiting factor here is the SATA bus and not the SSD.

Linux boots fast, and its quite stable on this machine. When I first had it there were some idiosyncrasies but an update a while ago made these disappear. The only issue I have so far is with the GPU which isn't surprising given Nvidia's attitude toward Linux and the fact that this machine has a hybrid graphics solution courtesy of Nivida's optimus technology. One is the integrated GPU that comes fixed to the CPU, it's slower but less power hungry than the discrete graphics processor which is slightly unstable on this unit. The issues have been largely fixed but I cannot put the machine to sleep if the Nvidia chip is running or it'll crash my graphical interface. However, Linux is still working fine and I can access it via the network over SSH, but having one GPU break the interface and render the machine unusable is not something a user wants to deal with. There are a few theories to the underlying cause, one of which was presented b a colleague who's got some experience with this issue and he thinks it might be a quirk with hybrid graphics and Intel's Skylake lineup, he reasons the CPU generation has other GPU related issues under Windows so this might be a CPU thing under Linux. Fortunately this is rarely an issue as I never use the discrete graphics unless gaming and plugged in to the power supply and the integrated Intel graphics are perfectly stable and they're fast enough for most uses. Since I rarely use the dedicated GPU, I don't bother activating it and therefore it's not worth the effort to troubleshoot it for the once per year I might use it.

I have noticed a flaw in this model though, I have had two of them because a power surge broke one of them. The surge was caused by a faulty UPS which was ironically supposed to protect them from such surges. I've since recycled the faulty UPS. Due to the fact I've owned two identical machines, I know this flaw is not a defect in my unit but either a design flaw, oversight, or some kind of independent fan control that fails to do its job properly. The flaw involves the small fan, this model has two fans and the small one will never activate even of it shuts down due to overheating. This happened to me 5 or 6 times and it took a while to narrow down the issue to overheating. The hinge exhaust design looks appealing and leaves room for ports but it can easily be made to not work properly as hot air can be sucked into the cold air intake and the entire system can be restricted by the closed lid. My model comes with a large intake on the bottom to help reduce the issue but I'm still not very fond of the design for laptops with a thermal output above the "thin and light" laptop range.

Once I found that the motherboard never sends power or signal to the fan on both units I have owned, I took matters into my own hands and soldered control and power wires from the working fan to the not working fan and now they both spin up together. I should have used good quality solder as my solder had an air bubble which exploded and propelled solder into the case, I tracked it all down and the only glob that proved to be an issue was one that shorted my audio chips. I eventually ended up having to pull apart the cooling system to access the audio chips and fix the short circuit which is why I replaced the old thermal compound since it cannot be reused after the heat spreader is removed. I found that this laptop had really poor thermal compound which applied badly, the quality was comparable to what one might find in a MacBook Pro which aren't known for having goo thermal performance. After the modifications and repairs to my cooling system, the temperatures dropped by 10 degrees. Crashes due to overheating no longer happen. My fans spin less because the load on one fan is split between two. And my battery life increased by 30 minutes, a five percent increase in battery life is quite a large gain from merely improving the thermal performance.

What I learned is that laptops in general are not designed for performance, and after market desktop PC thermal paste is a significant improvement over the factory applied paste on this machine and many other models. Checking if your fans work is a must and knowing how to get them both to work is also ideal.

My next laptop will be checked and stress tested on the first day I own it, and I will also consider upgrading the thermal paste if needed and maybe fixing the fans if they don't work as advertised.

Inside the back plate. mostly plastic but at least it won't burn you when the unit runs hot like my old MacBook did.

Inside with new SSD before cooling upgrade.

The fan that would not function

The power wire I soldered to the working fan.

Soldered the power wire to the not working fan

My makeshift cable management

Added the PWM control line jumper from the good to the bad fan.

Close up of my mistake attaching the control wire, and I also noticed the fan plug was broken so I made it work.

Both wires on the working fan side. That was an easy joint relative to the rest of the procedure.

My GPU with bad thermal compound, I had to scrape it off because it was hard as a rock, that's not what should be expected. Scraping thermal compound off a GPU with exposed SMD parts on the package is really risky and I took great care not to damage anything.

Please note: This WILL VOID YOUR WARRANTY and also annoy anyone working inside the machine later in its life. Do this at your own risk. If you do this, unplug it from power in case you short something, use anti-static equipment, and don't repeat my mistakes like accidentally breaking the fan's plug or having solder explode onto the motherboard. But you should only do this if you know what you are doing and are prepared to take the risk personally, you'll have nobody to blame except yourself if it fails to boot. This isn't trivial maintenance or upgrades such as blowing out dust or upgrading the storage respectively.