11.5.10 to R12.1.1 upgrade patching (6678700) performance issues

Hi,
We are doing test iterations of R12.1.1  upgrade from 11.5.10 .  Both database and appl node are in separate machines

1st iterations :    Non Rac database  , with 11.2.0.3    : Db size  550 GB

Db node :   32 GB Ram , cpu 2 
appltop node : 32 gb ram , cpu 2
SGA size : 2GB

number of workers :4   , batch size :  1000

R12.1.1 apps binaries : 32 bit

This iteration took around 50 hours to complete

2nd iteration

2 node Rac database   , with 11.2.0.3     : Db  size 550GB

DB node : 64 GB Ram  .  cpu 8
11.2.0.3 Grid /cluster installed
SGA size : 2G


R12.1.1 apps binaries : 64 bit

Appltop node : 32 G , cpu 8

number of workers : 12 ,  batch size 4

This iteration took around 70 hours to complete.

I expected the 2nd iteration to finish faster than the 1st but instead it took more time.      I am thinking it is a database performance issue.