I use guix 1.3, and a simple guix install takes forever. It hangs 2-10 minutes in the profile build phase.
I have a NVME drive, and see 10-80 MB/sec IO Write in this timeframe.

In the terminal I see: "building profile with 159 packages..."
Then I have to wait 5 minutes. 

I assume it hard-linking of packages because  I use ext4.

this behavior is machine specific. On the machines that are affected it occurs pretty consistent. But there are exceptions; when I install
a very small new package, the build time sometimes is in the 30 second range. But typically it takes 5 minutes.