ThinkPad X13 Gen 4 with AMD 7840U
My X390 bricked a few years ago after I lost power during a BIOS update, without warranty, and I needed some kind of usable on-the-go backup laptop.
In December, Lenovo DE had 30-40% discounts on some of the models, and the X13 Gen 4 AMD looked VERY interesting! Given uncertainty about RAM, SSD, and what else prices, I decided to get it. Compared to Framework 13" which is more expensive now.
After getting it, I had mixed feelings: 100% worse screen than my work MBP, okayish keyboard but it’s small and light! So my criteria would be to keep it as long as it wouldn’t run SIGNIFICANTLY slower than my PC that needs ~160W idling. I didn’t have any ready to go Elixir project to stress the CPU/MEM so I used “jj”. I compile it every 1st Wednesday of the month when the new release drops! Oh, and apparently, run all tests too, because it’s installed via Nix flake.
The setup:
- PC
- AMD Ryzen 9 5950X (16 cores)
- 32GB DDR4 3200MHz
- MBP M1
- 8 Core CPU (6P+2E)
- 32GB
- ThinkPad X13 Gen 4
- 7840U 8 Cores
- 32GB LPDDR5x-6400
All in “power” mode, with connected power cable.
A simple benchmark, with empty “target” directory in “jj” repository
| MBP M1 | ThinkPad X13 Gen 4 7840U | PC 5950X | |
|---|---|---|---|
| cargo build | 51s | 48s | 35s |
| cargo test | 360s | 193s | 124s |
I’m sure the M4 10 Core in MacBook Air would be faster than any of them, and no active cooling too, but then for 32GB RAM, 1 SSD and 3y warranty it wouldn’t cost 1000€, but 2100€.