Hello, the main advantage of SSDs is much reduced sensitivity to mechanical shocks and vibrations compared to traditional rotating HDDs. A few months ago there was a speed advantage in reading SSDs over HDDs, but writing them was slower - I guess this is changing, too, but we have conducted no comparisons. The concrete bottleneck during analysis depends on many factors, including the concrete model and mesh. According to our observations, RAM memory access is typically the weakest link. Saving results can also significantly affect the performance, if the disk is very fragmented and/or very many results are stored (e.g., after each step instead of only every 10th step).
I assume you have already read the article "I plan to buy a new PC to run ATENA on it, what do you recommend?" from out FAQ page at http://www.cervenka.cz/faq