lammert - 4:39 am on May 30, 2009 (gmt 0) Partitioning an office network over multiple gigabit switches should not be necessary under normal circumstances. There may however be other problems in your setup which practically limit the speed to 100 mbit/sec.
You can connect mixed Gb, 100Mb and 10Mb devices one one single gigabit switch and still get gigabit connection speeds between any two attached devices which support gigabit speeds. I have such a configuration running with a 3Com Gigabit switch without problems. Transfer speeds between my desktop and server are around 30 megabytes per second independent on other devices attached to the switch (100mbit/sec ADSL router, 10mbit/sec printer server)
Partitioning an office network over multiple gigabit switches should not be necessary under normal circumstances.
There may however be other problems in your setup which practically limit the speed to 100 mbit/sec.
The best way to test it is to disconnect all devices from your switch, except the NAS and your Gigabit laptop. If you get speeds around 30 megabyte/sec sustained (the maximum for most 32bit PCI network cards), your Windows settings and cables are fine.
Now attach more devices and see when the speeds falls. With every new device, an intelligent switch will only shortly slow down the speed when a slow device is attached. Once it has recorded the MAC address of the newly attached device, it will only slow down traffic to or from that MAC address, but allow high speed access between all other MAC addresses. If this is not the case with your switch, it is either a "switched" hub which requires manual configuration, or effectively a hub without routing intelligence.