Re: Random network speeds
Depending on many factors your results will vary depending on file size, server load, client and server configuration, suns spots and gremlins.
You didn't mention how large or small the file sizes were so, diagnosing what issues you may have are would be no more than armchair quarterbacking at best.
There are some tweaks that you can apply as far as buffering and rfc adjustments; take a look at nitro.ucsc.edu for links to documentation that will assist you with steps you can take to eliminate the OS as your culprit.
You will not reach maximum throughput with smaller files.
You will note that speeds will ramp up incrementally depending on your client/server configuration as capabilities are negotiated.
Once you have done all that you dare at the OS level, it is time to look at the capabilities of the systems hardware and underlying infrastructure.
I have seen mid range managed 10/100 switches out perform consumer grade gigabit switches and I've seen poorly configured managed switches drag large networks down to a crawl.
Even a thousand-mile journey begins with the first step.
Fall down seven times, get up eight.