X100e Project for Christmas

[TitoLabieno]

Hello! The Christmas season is around the corner and I'll be having some spare time. I'm thinking about taking care of my old X100e which has been on reserve for a few years. It is a fairly slow machine and it can't even run Windows 7/10 smoothly due to the mediocre CPU it has, but it will be funny to tinker a bit. It is also a "different" project, as I have seen very few machines like those in use. I know it is a cheap consumer grade Thinkpad, but it is special for me.
This is what I'm planning to do:
1. Opening and cleaning it inside. That includes the heatsink fan, reapplying fresh thermal paste and removing the dust it might have.
2. Upgrading the WLAN card. I have a spare Centrino Advanced-N 6205. That card is tricky, it works fine but I replaced it from a T430 because I needed Wi-Fi AC and bluetooth. I have tried it on other old laptops (Asus, Dell, MSI...) but it refuses to work under Windows (haven't tested it on Linux). It is properly recognized but device manager said "This device cannot be started" with a warning sign. It has lenovo markings and FRU numbers written in it, does it have a custom Lenovo firmware which prevents it being used on other laptops? Also, does the X100e BIOS have a WLAN card whitelist?
3. Dropping a new system there. It has a spinning Hitachi HDD, which is not that fast but the bottleneck was the CPU anyways. I'll probably install a light *nix there (any recommendation here?) as the only Windows version which worked fine was XP and it is not recommended due to security concerns.
4. Installing a new CMOS battery. The one it has is already dead, and being a low-grade device, it is not as serviceable as any other X-T series. You have to literally remove the motherboard (full disassembly) to reach the CMOS battery.
5. Trying to improve the cooling. That Athlon CPU is hot as the sun running Windows. I wonder if kryonaut paste+*nix will make it better... Anyways, if you know any "hack" or way to reduce the heat it generates (I have very limited experience with old laptop AMD CPUs), let me know.
6. RAM: Already maxed out. Years ago I was able to get some 2GB modules, so with 4GB (DDR2) it is more than enough for anything with that CPU.

I don't intend to use it as a daily driver as it is too slow, but it will be a funny little project. It might be a good music/video player on the living room. The battery still last an hour or more even with that power hungry CPU, and the rest machine is in pristine condition (I took care of it).
Do you know any mod I could perform on it appart from what I have mentioned? Last time I took it appart was many years ago.

[axur-delmeria]

The X100e has always been hot. You can try Linux and undervolt the processor using phc-k8. You can grab the source code at https://github.com/cablespaghetti/phc-k8 because the linux-phc.org site is dead.

TBH I doubt even Kryonaut can help. You probably need liquid metal to get the temps down by a significant margin.

I recommend upgrading from HDD to SSD.

[TitoLabieno]

Yes, a new SSD is always a nice addition, something like a 120GB Crucial BX500 for 20€ should be good enough. However it was intended as a "low-cost" project, the only component I needed to buy was the CMOS battery as I have everything else. I'll consider it. Thank you very much, I'll definitely try to undervolt that Athlon!