Invest into SAS drives on a pure mysql box, with a small dataset?

Im thinking of moving mysql DB onto its own server. Should I invest into 15k rpm SAS drives, over standard SATA ones? My dataset is only 450mb... grows at about 40mb/month. The server would have 4GB of ram, and would also run an instance of memcached.

it's not about the size, but the speed you require. SAS are lot faster. However, because the dataset is ~0.5GB and you have 4GB and the grow rate is so slow, you might as well just load everything into memory (mysql cache) and not worry about the hard disk speed.

Such a small dataset should work fine out of memory. But if you want to invest in a performance disk, get a solid state disk. That can outperform any SAS disk out there.