The PSN speedtester has always been like this for me.
When I test the internet connection on my ps4 I get 30.5Mbps Download and 5.7Mbps Upload.
The results on ps3 are even worse.
If I do a speed test on my xbox one it say 70Mbps download and 18Mbps Upload.
I think the problem is that the Playstation speed test servers are just slow as download speeds when downloading from PSN seem normal.
Although I would just like to add that if you are using a Bthomehub 4 or homehub 5 then go into the hubs settings and switch off smart setup as that can slow down speeds on consoles as well as give the wrong MTU.