Did you even compile on a RAM drive? If not - now you know, why...
No, what is the difference in comparison to a desktop (7200rpm produced in the last 2-3 years) hard disk?
I would have upgraded to a ssd, but looking at the reports on the internet, there is no big difference, that's why I've not upgraded.
As far as I can tell disk performance will be important only to the linking phase.