I have played around for both.
RamDisk is good program if you don't restart your computer and you have extra ram. It will help load times of many programs and I used it for maps and such which helped.
RamCache did really help with some load times and increased the speed of my SSD and M.2 drive until I decided to put my M.2s in RAID 0. At that point it actually slowed things down.
So RamCache is good if you are looking for some extra speed and help with some writes to the SSD.
Panteks Enthoo Elite / Asus x299 Rampage VI Extreme / Intel I9-7900X / Corsair Dominator RGB 3200MHz
MSI GTX 1080 TI / 2x Intel 900p / Samsung 970 Pro 512GB
Samsung 850 PRO 512GB / Western Digital Gold 8TB HD
Corsair AX 1200i / Corsair Platinum K95 / Asus Chakram
Acer XB321HK 4k, IPS, G-sync Monitor / Water Cooled / Asus G571JT Laptop