The audio processing speed is dependent entirely on the speed of the CPU and RAM in the machine. Storing the DAW software itself on a slow hard drive will not have any effect at all on the processing speed.
What will be critical however is where you store the audio that you are working with. Most DAW's will buffer audio to a certain extent, mitigating the ...
I have replaced the stock drive in my macbook with a 500 gb hard drive with 4gb flash memory. It automatically copies the most used files to the flash. Not nearly as fast as a real ssd though.
Wouldn't it be a better option to have a (perhaps smaller) ssd for your OS and applications, and put a normal 500gb or 750gb drive in place of the dvd drive for your ...
They do argument, that the OS does not need to run on a fast hard drive
That maybe made sense a couple of years ago when SSDs were expensive and small, so you'd use them for the most critical data only.
These days, the price difference is small enough to just go for the SSD for everything except archival storage.
I have two computers from the same year, ...
I have an SSD in my Macbook, love it.
However, be aware that the Komplete factory library takes up around 200GB, even with a lot of the Kontakt patches in their compressed states. That doesn't leave you much room for the OS or anything else. I store Komplete (and all other big libraries) on an external drive. No other choice really.