Gigabit direct connection Intel 82566 DC 2 & Vista

Dear PapaBear, thank you very much for your attention!
I answer to your questions below!

Have you tried a known good cable?

I'm using the cable that comes with the NAS, is it reliable?
If not, can you suggest me a known good cable?

Have you had any other network connection problems with this NIC?

I've never had problems with the nic of my PC, but I've never used it at 1 GB / s !

How old is the NV+?

The NV+ is pretty new, I've bought it in july, but not used it very much.

What lights are lit on the NIC ports when you first start and are the still lit when the NAS goes off line?

When the NIC is working there is a fixed yellow light and a blinking green light for network activity.
As soon as it blocks again I tell you what it does when it's blocked.

I tell you one more thing that I think is important: these are the network errors of my NIC:


Errori di rete [Ethernet 1]

Negoziazione automatica 7
Pacchetti danneggiati 0
Disconnetti 0
Portante False 7
Errori inattività 255
Errori di collegamento 0
Errori di ricezione 179
Errori di simbolo 15
Tag VLAN 0
Ritrasmissioni TCP 23
Ritrasmissioni TCP non recuperate 15

And I ask you some more questions: what should be the approximate speed of file transfer with a GB direct connection?
Can I use Jumbo frame with direct connection? Would a GB switch give more speed than a direct connection?

Thank you very much in advance!