Well for starters, you don't NEED to use a cache pool. You can use a single SSD if you'd like as a cache drive. You need 2 drives to make a cache pool though which is what I'm using. I use 2 x 480GB Intel 730's in my cache pool configured in RAID0 so it gives me about 960GB on the pool. I do this because I copy large amounts of data daily (backups) and I also have some cache only shares (meaning they stay on the cache pool and never get moved to the protected array) such as my Downloads share and my DVR share. For any share that is not cache only, the cache acts as a resting place for data before it gets moved to the protected array. You can schedule the data to move at certain times or certain intervals. Mine is every 2 hours I believe.