First the basics....
My network has a single server with 70 users (all 2000 or XP pro). The server is a 6 month old Dell Poweredge 6650 (running 2003 standard server) with dual 3GHz xeons, 3.5GB RAM, and a 150GB RAID 5 array. Quite a beefy machine but it does do absolutely everything (AD controller, DNS/DHCP, file server, Exchange, fax, plus about 10 other apps).
Our network is cabled with CAT 5. We have 3 switches each daisy chained off the other. One is a netgear 1GB switch (although only the server and a couple of other PC's have 1Gb cards), one is a HP pro curve 10/100 and one an unbranded 10/100 switch.
The setup is not ideal and in the long run I want to add a couple of servers and upgrade most of the PC's to 1Gb cards.
Up until the last few days everything has been fine. But certain users have now started to whinge that the system is "slow". In particluar it takes 4 to 5 seconds for server based apps and documents to open. Very vague I know but we are talking end users here! Not all users are reporting problems but not all users use the system as intensively as others and some are just down right unobservant!
Nothing has been changed on the server in the last couple of days. I have checked task manager and there is a consistently low cpu and memory usage. Initially I suspected it may be a problem with one of the switches but the affected users are not connected to one particular switch.
I realise that it may still be a server based issue but can anybody suggest some tools I can use to identify whether I have a problem with my network? I would prefer in built (ie free!)Windows 2003 tools although if there are any particularly effective 3rd party tools I will consider buying them.
Hope you can help