A-sync Speed over Gigabit LAN Ethernet File Transfer

I have a strange problem with transferring files between 2 computers connected to each other through an ethernet cable. Both PCs have on-board gigabit ethernet ports. Aside from the different hardwares, the softwa开发者_JAVA技巧res (especially network settings) are configured almost the same, with Windows 7 x64 etc. Tests have been taken with and without antivirus programs running with no difference. Duplex settings are auto negotiation. Jumbo packets (~9MB) are enabled (usually I'm transferring really large files). Hard drives are not a problem, since local transfer speed within a computer is around 100 MB/s.

Now if I am on PC1, and accessing shared files on PC2: Transferring files from PC1 to PC2 is very fast, usually in the range of 60 MB/s (see results below from LAN SpeedTest). But the opposite (transferring from PC2 to PC1) is really slow, about 10 MB/s. Speed Test 1

If I am on PC2, and accessing PC1: Transferring files from PC2 to PC1 is slow (see speed test below - it's actually a little slower than when I'm transferring files and reading the speed report from Windows), while the opposite is fast (also about 60 MB/s like in the first case) (I would post link 2 here but it does not allow me to since I am new)

So what causes this?

TIA

It might have to do with the hard drive write speed of PC1. The read speed is fast enough to send data to PC2, but the write speed is not fast enough to receive the data from PC2.

This may be a silly question but when you say the computers are connected via an Ethernet cable do you mean directly connected or via a switch? If directly connected, are you using a crossover Ethernet cable or straight-through cable? If using a straight-through cable, I would say that one or both of the cards are failing to auto-sense if they have that capability. Also auto-duplex and auto-speed settings have been known to fail in the past, try setting them manually as well.