Question : Problem: Poor Network Utilization (throughput)

Network Throughput Utilization:
Much of our network is Cat5e, we were thinking of upgrading everything to cat 6.  After running some network utilization tests, I found that we are only obtaining 300 megabits per second throughput, and averaging more closing to 200 megabits per second. I tried this through both cat5e and cat6, expecting Cat6 to perform much faster, however I saw no improvement.

So I set up a test network.  Two computers, one with Windows Server 2003, the second with Vista.  Using a Cat6 crossover cable, I connected the two 1000 megabit NICs.  Again, I could only achieve apprx. 350 megabits per second.

I know in every situation that my connections are all 1000 megabit.  But I do not know what is causing the drastic decrease in network utilization, nor how to fix it.

Thanks for your help!

Answer : Problem: Poor Network Utilization (throughput)

There is ZERO performance difference between CAT5e and CAT6
Network througput has too many other factors, like system memory, cache size, disk i/o, etc. The max will never get anywhere close to even 900Mb.
Try Windows 2008 with Vista client on a gigabit switch (not crossover) and see the difference.
When you put a crossover between two Gigabit NIC's, did you make a special Gigabit crossover, or did you use a standard Ethernet crossover? If standard, then you were limited to 100Mb anyway, and two hosts on one segment requires half-duplex, so you screwed yourself on the test. That's why I suggest using a real switch between them