Problem with Realtek NIC

[Ivan Radovanovic]

Hello,
I am experiencing weird problem with Realtek network card under FreeBSD. 
Recently (10 days ago) I cvsup-ed to RELENG_7, so that may be the cause 
of problem too (although I noticed this only last 2-3 days).
Network card looses connectivity in some way after around 1 hour of 
being connected - "in some way" because I am able to ping gateway for 
example but large number of packets is dropped (like first 15 going 
through, then 40 without reply and so on). If I do
ifconfig re0 down and after that ifconfig re0 up everything is restored 
to working state for another hour. I tested the same machine under 
windows and everything seems to work normaly. I tried ifconfig re0 
-txcsum -rxcsum but that didn't have any effect.
Data from dmesg
re0: <RealTek 8169/8169S/8169SB(L)/8110S/8110SB(L) Gigabit Ethernet> 
port 0xc400-0xc4ff mem 0xfeaff800-0xfeaff8ff irq 20 at device 4.0 on pci2
re0: Chip rev. 0x10000000
re0: MAC rev. 0x00000000
miibus0: <MII bus> on re0
rgephy0: <RTL8169S/8110S/8211B media interface> PHY 1 on miibus0
rgephy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto

Any help would be greatly appreciated

Regards,
Ivan