Weird - nvidia drivers lock up connection tray

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After installing a nvidia GF740, following error conditions happens:

Upon wake-up after going into 1.st. standby the network notification tray has a red crossed icon.

Clicking settings->network connections are delayed (there is a hanging condition going on).

When the net.window appears, it shows "network cable unplugged". Despite this it is possible to browse aka using the net-connection.

Trying manually to goto standby again hangs the puter with the sign "preparing to standby" (only a 4-sec power-off is possible)

I have tried (more and less exclusive each other)

* Several version of the nvidia driver
* Even disable the Mobo network controller hangs the connection tray (if we assume that the network drivers and services are not loaded/active). This makes it weird.
* Entirely removing network s/w components.
* Installing a minimal nvidia driver part (and not all the other additional circus that is possible - like auto update).

The standby works on a restore of a basic windows (no drivers and progs but with GF740 card ). So therefore I am certain it has to do with the nvidia stuff.

Data about the silicon:

* Gigabyte GA-H61M-D2H-USB3 v1.2 mobo (1155 socket with Intel I3-3240)
* The net.chip is a Qualcomm Atheros 8161 gigabit
* The GF 740 is of brand Palit (quite cheap, wonder if there is some h/w flaws on this discound model. Maybe a few more bucks for an Asus model would have been better)

Data about settings:

* The standby BIOS is S3 (suspend to ram)
* No over-stupid-clocking
* No special net.card settings, like wol)
* Tried the oldest/newest GF740 drivers aka 337.88 and 350.12 (and several in between)

My immediate sol. is to disable stby and only have monitor/disk stby. But i wouldf be much more happy with the full S3 stby