OS vs "Code Base" on SSD vs HDD

Question

I have a HDD and also a SSD in my Windows computer. Also I have a C++ code base that spend nearly one hour to compile. I'm keeping the code base in my HDD and installed the OS in SSD. But I have seen some people use a secondary SSD for the same code base, and they can compile it withing 10 min. But in my case, I don't have a secondary SSD. So my plan is, move OS to HDD and move code-base to SSD.

Will it impact OS performance in considerable way? Will it help to build the code base faster considering overall change?

Answer 1

Changing from SSD to HDD will most likely reduce your OS speed.

There is already an answer to this question, that You can find in this post:
https://stackoverflow.com/questions/15199356/speed-up-compile-time-with-ssd

Answer 2

It will reduce your OS speed, and maybe increase your build speed. I imagine there is a lot of reading with lots of files during the build process, and writing new files. SSDs have less latency when starting a read, and are more parallel because all parts of the storage can be accessed at once - these are both good for reading lots of files. They also have higher throughput.

However, this test from Joel Spolsky resulted in compile time not improving. The bottom line is that the CPU is what really matters. It might improve, but a better CPU would really help, and maybe faster/more memory.

Here's another more recent test I found.