Teradata Optimization for large table(20 billion rows) - response (2) by Shelley

The estimated time in an explain is actually a cost, not a time value (even though it says time).
You cannot predict performance time by the number of amps. Performance time is affected by the hardware platform and workload on the system among other things.
Is your large table partitioned? Are you using the PI or a secondary index in your joins?
Are stats collected and up to date?
There is not enough information in this request to even guess at how long your query will take to run.
--Shelley