My home network is a Windows workgroup with two Netgear GS108 rev 3 gigabit unmanaged switches that can handle 9000 byte giant frames. Currently, three machines on the network link at gigabit speed all running Windows XP:
- The media server, a Tyan 2460 based dual Athlon 1.2 MP with 3 gigabytes of DDR ECC RAM, a 64 bit 33 mHz bus, 3Ware 8 port 7400 RAID controller with
- A desktop using the Via P4X266 chipset, 2.6 gHz P4, 2 gigs of DDR ECC ram; 32 bit PCI at 33 mHz, a Promise ATA100 hard disk controller, and a Pro
- The newest machine, ironically built for digital piano; a Gigabyte PCI Express socket 939 design using the NForce 4 chipset, onboard gigabit Ethernet, 4 gigabytes of dual channel 400 mHz DDR, a single 80 gig Seagate ATA100 disk on the built-in controller.
Using the latest (August) version of the Intel drivers, which actually seem a little worse than the March release, this is what I get for large files, using the standard 1500 byte frame size:
Server --> machine 3: 130 mb/sec machine 3 -> Server: 160 mb/sec Server --> machine 2: 130 mb/sec machine 2 --> server: 90 mb/sec (was 130 with the March drivers)
CPU usage on the server is about 20% or less. CPU usage on machine 2 is around 40% CPU usage on machine 3 is around 20-30%
Machine 2, in fact, is no better on the uplink than one of my Centrino laptops, which manages 85 mb/sec up/down over a 100 megabit link via the built-in Realtek controller, with CPU usage at 75% !
Giant frames set to 9000 result in about a 7% speed loss, but uplink on machine 2 drops to near zero. Buffer parameters for the Intel cards have been adjusted to the max, 2048 receive, 2048 send. Disks are in a defragmented state. These measurements were taken without other network activity.
Your comments on the likely bottlenecks are appreciated.