Unacceptable Latency on IPSec Site to Site

Hi,

I have replaced 5-6 boxes from SG to XG this week for few of my customers. But immediately after the change, I have been noticing high latency on the traffic passing via IPSec and sluggishness on application's traffic. I am using XG85 on the branches and XG125 on HO and concurrent user per branch is less than 5. I can ping WAN IP with latency of less than 5ms but branches LAN latency is sometime 3 digits and 2 digits usually. 

Both the boxes are with only base licenses on it. Looking for some quick solutions. 

Regards,

Rupesh