Safari stalls when scrolling or zoom

Question

My iPhone 6 using iOS 8.1 has a problem with Safari.  When scrolling up or down the page freezes for a while, or when zooming again it freezes for a time.  If you keep the page moving up & down its fine.  Took phone back to Apple store where they found Cameralert & Waze had crashed a few times & reinstalled the operating system.  This improved it for a few days.
Returned the next week & phone was replaced but still have same problem.  Google Chrome works so much better & I would use it more but when clicking on a link Safari always opens.

Answer 1

K --
What "Network Optimizer" did you try?
Please look over this list, and go through them all, OK?
Then tell us how you're doing . . .
1. Empty your cache & History settings via the Safari menu
Any improvement?
2. Quit Safati.Trash your Icons Folder:
HD>Users>Home>YourName>Library>Safari -->Icons
Restart Safari and a new folder will be automatically regenerated.
(This folder saves favicons of all the sites you visit. Needs cleaning periodically -- or you can change that file's preferences to "Read Only"
rather than "Read & Write." This will keep it from growing in size.)
Restart Safari. Is it better?
3. Launch Font Book and check all fonts for duplicates. A duplicated font will have a bullet beside the font family and you can resolve duplicates by selecting the font and at the menu bar, go to Edit > Resolve Duplicates.
Do this for each font with a bullet next to it. Restart Safari & Test.
If you're still having problems:
4. Shut down your computer . . . unplug the computer, modem, and router, if you have one. Let everything sit for 2-3 minutes. Plug everything back in, start up your modem & router. After the lights settle in, then restart your computer.
5. Do you have internet apps SpeedDownload, iGetter, PithHelmet, Acid Search, Safari Enhancer ? Or Norton or Virex? Sometimes non-apple internet apps need updating or uninstalling. If you do, let us know which ones and which version, please.
6. Check your Syster Preferences>Network>Automatic>Built-in Ethernet Settings. Have you chosen "Using DHCP?" And under the Tab "Proxies" is anything checked off? If so, uncheck all.
Hope this helps