What is the motherboard where you use this?
Are you sure that cables is okay ?
I m running my MT on Asus Intel 82801 chipset, like I said I alredy have Realtek - RTL- 8169 Gigabit ether (x4 ports) runing very stable.
But I need extra 4x ports and all they have was 44gv - VIA vt6122 ether (they call it green card because they cut some 1-2w power consumption lol and they save the world).
like meshnet said "Ports just drop off, and you have to disable/enable them to make them work" and sometimes MT freeze need hard reboot.
Mikrotik is excellent product, but hardware they selling is "peace of crap" - sorry
I m using all R52, R52H and R5H (witch every 1 or 2 of 5 cards have problem) but last time I order UBIQUITY UB5 5Ghz just for 33$ and I think this is most beautiful peace of hardware that I ever have its like baying cisco for 33$.
I cant never understand how MT gays can compere intel or old 3com Cyclone or Tornado (stability, extremely reliable, 5 years warranty) ether with VIA (its made in some province of china for 1$ per peace lol.)