Yes, that's no problem. :-) Can only recommend.

Why do I only get 100mbs with this card and 1000mbs with the board's standard card? I should now be getting my 10000mbs.

The card is compatible with pretty much every mainboard you can buy on digitec. Maybe you should check if you have a free PCI slot and if it is not covered by the graphics card.

Yes, but it only reaches the speed of 10 Mbit in the first few seconds. After that it drops and fluctuates between around 4 and 7 Mbit/s.