Hard disks, USB drives, SD cards — anything with storage space must be partitioned. An unpartitioned drive can’t be used until it contains at least one partition, but a drive can contain multiple partitions.
If you partition a HARD DRIVE, the first partitions perform better than the last ones because they're situated at the outermost tracks which have the highest transfer rates. People often do this to make sure, for example, that the OS is located on the fasted part of the hard drive. But SSDs have the same transfer rates for all sectors, so this does not apply to them. There's no reason to partition an SSD in the hopes that you can get better performance out of one partition than another.