Optane 32gb for caching a RAID1 SATA SSD pair is pretty slow on random write bandwidth. I am thinking to change it to a P3700 to gain some speed.
Intel Optane 960GB 905P 2.5" x 15mm, U.2, PCIe 3.0 x4, 3D XPoint Internal SSD 735858342872 | eBay
Optane SSD 905P Series. Part Number.
www.ebay.com
Or the P4800x 100gb may be good for the $