I had a dell computer with an SSD and on the SSD itself it said 3Gbps. They sent me a replacement laptop and the ssd is thinner (still 2.5 inch, but it's thinner) but I'm trying to see if it's 6gbps because I'm trying to figure out which one to keep. I used "speccy" but it didn't give me speeds. Any ideas?
Try using CrystalDiskInfo. If the SSD is running at 6Gb/s (6 gigabits per second, or 600 megabytes per second theoretical maximum speed), the Transfer Mode field will read SATA/600.
Your SSD, as well as the motherboard in your computer, must both support SATA 6Gb/s in order for the SSD to operate in the SATA/600 transfer mode. If either one or both support only SATA 3Gb/s, this field will read SATA/300.