GIS app loading very slow through F5 LTM

Hi, 
Beside the below Comments, 

1- try to use Performance layer 4 for your GIS Virtual server , doing this ( BIGIP doesn't termintate SSL also doesn't perform HTTP pasrsing ). 

2- Take a PCAP and check the response time for this specific URI. 

3- Take HAR file from your browser to see this Latency from end user perspective. 

you can also bypass BIGIP from the path and access the application server directly for this URI, and check if the perfomance improved. 

All of the steps just to isolate, because this slowness maybe from the Application server. 

Also it's very important to ask the application developer/owner if this URI perform heavy DB Queries or not. 

Take also Pcap via standard Virtual server, and check if you encounter TCP error messages regarding Latencies like ( TCP Zero Window , Window Full ..... ) 

https://my.f5.com/manage/s/article/K35612380