Mirroring will indeed affect performance, the SSD's will be massively faster then any mechanical drives and will be constantly waiting on them.
Since you have AMD and AMD's RAID isn't something I'd ever trust you may be better off using a single SSD and then running an occasional backup/image operating to one of the older drives. Honestly RAID 5 or RAID 1 is a complete waste for a home user and gives you no protection against malware, encryption attacks, data corruption, or most other things that you'd want to be sure you protected against, all it'll do for you is allow for a single drive failure while staying running.
RAID5 with old drives and an AMD controller won't even give you a fraction of the performance of a single SSD, let alone two SSD's in RAID-0. RAID 5 should be done with a true RAID controller card to get great performance. If you are using an AMD system you can try updating the BIOS and installing the latest chipset and RAID drivers from the AMD website and then you may get not awful performance.
Since you have AMD and AMD's RAID isn't something I'd ever trust you may be better off using a single SSD and then running an occasional backup/image operating to one of the older drives. Honestly RAID 5 or RAID 1 is a complete waste for a home user and gives you no protection against malware, encryption attacks, data corruption, or most other things that you'd want to be sure you protected against, all it'll do for you is allow for a single drive failure while staying running.
RAID5 with old drives and an AMD controller won't even give you a fraction of the performance of a single SSD, let alone two SSD's in RAID-0. RAID 5 should be done with a true RAID controller card to get great performance. If you are using an AMD system you can try updating the BIOS and installing the latest chipset and RAID drivers from the AMD website and then you may get not awful performance.
