On many of the newer Cisco switches, there is a concept of platform memory. This is memory on the device similar to RAM on a PC and not the memory that is contained within the processor. You can get the memory levels from the following command: show memory plaform. Cisco switches 3650, 3850, 9300, 9400, 9500, etc. utilize this memory. It's very important to monitor this memory as Cisco has a number of memory leak bugs that will cause all kinds of terrible network issues and/or a crash of the switch. We have monitored this memory prior using SolarWinds. Do you have a sensor already built for this or is this a custom build? On SolarWinds, I use the following OIDs in a calculations to determine percent memory.
Memory Used: 220.127.116.11.18.104.22.168.22.214.171.124.1.12 Memory Free: 126.96.36.199.188.8.131.52.184.108.40.206.13