SharePoint Designer Performance Issue at the client side

Sometimes i have seen SharePoint performance issue at the client side - this can be due to many reason but you can give a try for below steps at client side and see if this helps you !

1. Close SharePoint Designer.

2. Clear your Internet Explorer's temporary Internet cache and close the browser.

3. Remove content in Folder %System Drive%\Users\%user%\AppData\Local\Microsoft\WebSiteCache).

4. Type %temp% at a run prompt and delete all the temp files in there.

5. Type temp at a run prompt and delete all the temp files in there.

6. Delete %APPDATA%\Microsoft\SharePoint Designer\ProxyAssemblyCache

7. Delete the contents of: %APPDATA%\Microsoft\Web Server Extensions\Cache 

8. Delete contents of %USERPROFILE%\AppData\Roaming\Microsoft\SharePoint Designer

you can also check @ server side - change with your URL

$app = Get-SPWebApplication http://abhi.interest.com

$app.ClientCallableSettings.ExecutionTimeout

Try to increase ClientCallableSettings.ExecutionTimeout values - 

$app.ClientCallableSettings.ExecutionTimeout = 5400000000

$app.Update()

Best of LUCK!