4 SATA drives and 1 M2 drive, but it would depend on what you currently have connected. That's the maximum number of drives that can be connected to the motherboard. The 4 SATA drives can be SSD or HDD as long as they are SATA. Just have to be aware of the size limitations of the Caddy's as per table below.
Hello, I have an alienware R8. I've added a SSD drive in it so I have 2 SSD drives and one HDD.How many SSD drives can I have in this computer? If I want to upgrade it further, can I add a hard drive or do I have to find bigger drives?Thanks in advance for your answer. Regards, Cyril  
How many SSD slot in a R8?