You may see a very long loading time when you try to open jb and REAL backend pages when using Win 8.1 + Kaspersky, you can find more info here.
The only fix we found was to switch off Kaspersky while we use Chrome. Later on, when you're finished editing the page you can turn it on again.
Due thin circulation of Win 8.1 (7,9%) and Kaspersky (5,5%) and the fact that many users still use no antivirus at all, 1 of 1000 visitors will face really page loading problems.
Fix This is not in our hands, fix has to be delivered by Kaspersky.