So I've got one of the infamous R8168 Realtek ethernet NIC, which have some problems under Linux. After some research, I found out I had to use the r8168 driver for this card (and not the r8169 which still loads when nothing else is available), which I did. So now everything works fine... Sort of.

My download and upload rates are more than halved compared to what I should get. When I test (with eg. speedtest) I get something like 20M (often 15M) in download and 30M in upload, but if I test under Windows (everything is otherwise identical: same ethernet cable, same connection, at the same time of the day (well 5 min apart)...), I get 50M upload/download (which is what I expect). Where can it come from? Here's some info:

~ # lspci
[...] 
06:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06) 


~ # modinfo r8168 
filename:       /lib/modules/3.2.1-gentoo-r2/net/r8168.ko
version:        8.027.00-NAPI
license:        GPL
description:    RealTek RTL-8168 Gigabit Ethernet driver
author:         Realtek and the Linux r8168 crew <[email protected]>
srcversion:     0A6E9F1D4E8E51DE4B6BEE3
alias:          pci:v00001186d00004300sv00001186sd00004B10bc*sc*i*
alias:          pci:v000010ECd00008168sv*sd*bc*sc*i*
depends:        
vermagic:       3.2.1-gentoo-r2 SMP mod_unload 
[...]

~ # mii-tool -v
eth0: negotiated 100baseTx-HD, link ok
  product info: vendor 00:07:32, model 17 rev 4
  basic mode:   autonegotiation enabled
  basic status: autonegotiation complete, link ok
  capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  advertising:  100baseTx-HD 10baseT-FD 10baseT-HD flow-control
  link partner: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD