Freezes on your dual-tuner subscription do not depend on the server you are connected to. Back-up server is used when the normal server is failed. If you have dual-login activated in your billing and if your subscription is dual-login subscription, it should be no problem with freezes. Otherwise, check your settings.
P.S. Complete your signature and describe your equipment, subscription(s), etc. Finally, provide a log-file when you experience freezes.
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