What will be the effect of disabling the cache? My load test vendor wants the run their load test after disabling the cache. Is running DBCC DROPCLEANBUFFERS and DBCC FREEPROCCACHE at the beginning of the query is the process to disable the cache?
Those will clear the data and plan caches. I don't think you can disable them but I imagine they meant 'clear'. Of course, this will have a significant negative effect on the server while it re-compiles incoming batches and fetches the required data from disk.