I suffered a slow i7 workstation with 32Gb RAM and solid state disks. Its fan is noisy. It was like this since I bought it second hand. So I thought it was normal for HP workstation since a few reviews also mentioned that Zbook can get hot and noisy.
It gets worse and worse until it becomes unbearable. I suddenly remembered my Asus A42 with i5 which because so slow despite constant defragmentation, until it failed to operate entirely. Its CPU burned. I replaced it with an i7.
I should have know about this but was in denial mode. Too lazy to open up the laptop until today. After a few mistakes, everything works as usual and cool. Luckily I have just bought a few pieces of 1mm and 0.5mm thermal pads and I still have spare thermal paste.
The ideal temperature of this laptop is now 50 degrees. Before that it was 80 degrees. It frightened me and may end up losing its CPU again.
Now it reminds me of my office PC. It could be due to worn out thermal paste also.
Not really solved. Only problem reduced but today it is much better. 2/2/2020.
I just go to BIOS setup and tick the fan always on on AC supply.
