DBCC CHECKDB WITH PHYSICAL_ONLY option runs slower compared to a Full DBCC CHECKDB? Is it possible for DBCC CHECKDB WITH PHYSICAL_ONLY to run slower compared to a full DBCC CHECKDB? The platform is SQL Server 2014 SP2.
According to Microsoft, no. 

DBCC CHECKDB Documentation


  PHYSICAL_ONLY
  Limits the checking to the integrity of the physical structure of the page and record headers and the allocation consistency of the database. This check is designed to provide a small overhead check of the physical consistency of the database, but it can also detect torn pages, checksum failures, and common hardware failures that can compromise a user's data.
  A full run of DBCC CHECKDB may take considerably longer to complete than earlier versions. 


I confirmed this by running DBCC CHECKDB against the same 50GB database twice, once with PHYSICAL_ONLY specified, and the other without any options set. The results:

 With physical_only:
 SQL Server Execution Times:
 CPU time = 46894 ms,  elapsed time = 61546 ms.

 All checks: 
 SQL Server Execution Times:
 CPU time = 247964 ms,  elapsed time = 263678 ms.


Having said all that, do you see that PHYSICAL_ONLY takes longer than a full check?

EDIT: Here's the results for a 320GB database:

With physical_only:
SQL Server Execution Times:
CPU time = 552805 ms,  elapsed time = 1218867 ms.

All checks:
SQL Server Execution Times:
CPU time = 2074875 ms,  elapsed time = 3007516 ms.


So, no - PHYSICAL_ONLY on databases larger than 200GB is not slower than a full check.