Using Windows 7 Ultimate and Windows Server 2008 R2 Two machines, connected via 1000base-T LAN with CAT5e, with a full duplex 1Gb switch between... and yes, I've tried swapping cables and ports. Server has two RAID5's, a 6 platter and an 8 platter. Workstation has two RAID5's, a 3 SSD and a 4 platter. Both sides using Intel iX CPU's and a RealTek 811xC chipset Gb LAN, same latest LAN drivers on both machines. Static IP, client in a Workgroup and Server a DC for a Domain (haven't tried joining the client to the domain yet). I am using Windows Explorer to COPY a 20GB file set... I've also tried xcopy and robocopy, with similar results. I have tried all the suggestions regarding network adapter settings regarding duplex, large packet offload, RDC, a few netsh changes (RSS and autotune), and a few others. Nothing has really affected the final transfer rate significantly to improve utilization (and backup speeds -- the whole point of this exercise). Server Disk1 to Server Disk 2: >250MB/s (Server disk I/O isn't an issue). Server Disk2 to Server Disk 1: >250MB/s (Server disk I/O isn't an issue). Workstation Disk1 to Disk2: >150MB/s (Workstation disk I/O isn't an issue). Workstation Disk2 to Disk1: >150MB/s (Workstation disk I/O isn't an issue). Now for I/O: first a baseline using the Server side Windows Explorer to copy from a mapped Client drive to a local Server drive: -- Server Disk1(D:) to Workstation Disk2(Z:): 91MB/s (near 100% LAN utilization). All looks good so far, but let's try the identical operation, but use the client's Windows Explorer to copy from a mapped Server drive to a local client drive: -- Workstation Disk2 to Server Disk2: 25MB/s declining to 17MB/s; occasionally as low as 9MB/s. Average about 20% utilization. It appears there is something in Windows 7 that prevents fast transmits; or something in Windows Server 2008 that blocks fast receives. I have set the client and server-side receive training to disabled, normal, highlyrestricted, and experimental, in various combinations. Again, nothing concrete to report as an improvement. What would the MS Gurus suggest I do with NetMonitor as far as capturing something worth their time to diagnose? ps: This type of transfer has low utilization whether copying to a server or to a client (pushing data). Yet pulling data from the client is always faster, as much as 3x.