ASP classic “execute” is incredibly slow on local server

I am executing these two cycles in Classic ASP:

for g=1 to 5000
    dummy=1
next

and

for g=1 to 5000
    execute("dummy=1")
next

On cloud server (Windows 2008 with IIS 7.5) these two cycles are executed in 0 seconds. On a local powerful machine (with Windows 10) the first cycle is executed in 0 seconds, the second one inabout 40 seconds. And every time I relaunch the same script, the execution time increases by some seconds!!

Tried on a second Windows 10 machine (IIS 10.0), same results.

Cannot understand what is happening, any ideas?

This is the script I'm using for testing:

<%
server.scripttimeout=9000000

starttime=now()
response.write "<b>Default method</b><br>Start time: "&starttime
response.flush  

for g=1 to 5000
    dummy=1
next

response.write "<br>End time: "&now()
response.write "<br>Time elapsed: "&datediff("s",starttime,now())&" seconds"

starttime=now()
response.write "<br><br><b>Execute method</b><br>Start time: "&starttime
response.flush  

for g=1 to 5000
    execute("dummy=1")
next

response.write "<br>End time time: "&now()
response.write "<br>Time elapsed: "&datediff("s",starttime,now())&" seconds"
%>

Please help!!!