I have a problem that I can't fully identify, and for which I've spent a lot of time testing and debugging, and nothing helped.
Computer network description:
Freshly (6 months) installed computer network, freshly wired network, managed 3Com switch, new IBM server x3200 series, all clients have XP on them. All service packs and updates are installed, all network card drivers are latest versions.
The problem is with two accounting applications that communicate with the server over shared folder mapped as a hard drive in My Computer. Both programs are flat file database based.
The problem is when programs slow down. Something happens and both of them become unbelievably slow, and then clients start calling me.
On all of the computers ESET NOD32 is installed, on the server NOD32 antivirus application options everything is disabled except file checking, and on the client computers options are left default.
There is SBS Domain installed in the network, and all computers log in in that network. There is no folder redirection.
Applications: No problems, except yesterday there were some problems with Exchange. I have installed some updates, and restarted and everything is OK now.
Directory service: All OK.
DNS Server: No problems.
File replication services: OK
Internet Explorer and Security: All OK.
System: All OK, except some printer problems with driver not installed on server. Mainly have connection with me connecting to terminal administration console.
netcps gives median transfer of about 32 megabytes per second on gigabit clients (All).
There is no firewall application installed, except the one built in SBS 2003.
Computer is defragmented, users normally use their files located on the share with no problem or speed slowdowns.
I have even gone so far to move all users from normal wired network to completely new CAT5 cables built in the electronic shop. Everything worked fine after I've installed that cables, and now people are again reporting slow performance.
The "SLOW" is defined by users click on some operation in in a program, and then everything halts for a period of time. That is extremely annoying and occurs on all computers in the network.
When I thought it is the Switch, I've replaced it with another one, and the problem persisted.
On the server there is Broadcom NetXtreme Gigabit Ethernet LAN card installed, newest IBM drivers, there is a screen shot attached of how the card is configured.
Other card is D-Link used for access to a ZyXel aDSL router that connects the LAN to the network. The Internet is over the SBS server.
The server is sufficiently powered, with two mirrored arrays, Dial Core Xeon, 2 GB of RAM.
Every computer and all network equipment is connected to an APC ups, server, switch and router to the Smart UPS that delivers pure sinewave and corrects the current.
I don't know what to add more, except - please help!
This problem is driving me nuts!