Tickrate - how many regular 'pulses' of updates and adjustments the server makes. If your server is 66 tickrate, it will update 66 times a second (think it's second) etc.
100 tickrate is most accurate if its recieving and sending out enough information, and isnt getting overloaded. 33 is most innaccurate, but requires the least bandwidth and cpu runtime to host properly.
Basically, as long as the server is up to it, and your net connection is up to it, 100tickrate is far more accurate, as it can send and recieve 100 updates to and from the CSS clients each second, if your client is set to send and recieve that many data packets but ofc its more stressful on your line if you set your rates up as such.