Improve performance by partitioning
Can partitioning the table help reduce the completion time?


No. Partitioning is not a performance feature, is used for other purposes. If the table has 120 million rows unpartitioned, it will also have 120 million rows after partitioning. Read How To Decide if You Should Use Table Partitioning.

If you want to improve performance you need to identify the bottleneck and address them appropriately. Is it a bad plan? Missing index? Slow IO? Slow CPU? Not enough RAM? Poor code? USe a methodology like Waits and Queues to identify the bottleneck.