By George, you've got it!
For someone who thinks that he's good at googling, I sure could use some improvement!
The key was the explanation link. While I had been close in my different tries, it goes to show that even when you sort-of-kinda-maybe-think you know what you're doing keep your paws off unless you know EXACTLY what you're doing.
The answer was definitively the Large Send Offload, but it was a little more tricky, at least to understand what really happened. Disabling it did do the trick, but now I have it working with a v2 enabled and it's working like a charm.
I'm going to detail what I think happened here for those who may have similar issues so that they (you) may be able to figure it out, as all adapters are different and may require slightly different settings.
I live in an area where until now the fastest upload speed I could get was 2 mbps, on a good day, it usually averages 1~1.5 mbps. Download speeds ranged between 5 ~ 20 mbps.
I do a lot of video work and I constantly upload large files to my servers. I got the computer described above about 8 months ago, and my old one (2 yrs old) stayed on my home network.
For a week or so, I have been cursing my ISP because internet was slower than usual and very glitchy. I tested my speed and got 20 down and 0.2 up, repeatedly. I was paying for 20/2 so I endured the long call and technology-challenged representative to "assist" me. Only option was to wait a week for a technician to come out to my house, but, he pointed out shooting down my prejudice, though not before me asking, that there was faster internet speeds available at my place. 200/20 which is 10 times what I had, so of course I went with it. In doing so the representative asked me to go in and swap my modem/router for a new one to handle the faster speeds.
When I replaced the modem/router I found that the download speeds went from 50/0.2 (after the new speed request but still with the old router) to 200/0.3~0.5 with the new router. I also had a E2000 Cisco Router that I turned into a switch, which had been also bogging down internet speed (now that they were much faster). But still the upload speed didn't really improve.
This long and winding story is so that you (reading this with a similar issue) might find the answer for your particular problem.
Looking back when I stated that the issue was in my computer since the old one was getting the high speeds was not entirely accurate. The "problem" was beyond my router, though the solution was in my settings with the LSO setting. The "problem" was not really a problem since what I see (guess) happened is that my ISP has been upgrading equipment, and the settings on my new pc became an issue while paradoxically not so in my old pc.
My old pc has a "Realtek PCIe GBE Family Controller" and with the IPv4 LSO setting enabled it was having no problems, under the new set of ISP circumstances. 200/20 mbps.
So when I compared the setting to my new computer, it never crossed my mind that disabling it would solve the issue.
My new pc has a *Atheros AR8161/8165 PCI-E Gigabit Ethernet Controller (NDIS 6.20).*This adapter has an "IPv4 LSO" setting plus a "IPv4 LSO v2" setting and a "IPv6 LSO v2" setting. I don't believe my ISP is using the IPv6.
In my quest to fix the issue I placed all the above setting to Enabled, to no avail, and in my fog didn't reverse those settings.
With all 3 Disabled, it worked fine, but I got a 5~10% improvement on the upload speed with the IPv4 LSO v2 enabled and the other disabled.
There is no way that the ISP's representative on the phone could know this, so calling them would not/did not solve the issue. Even waiting a week for the technician most likely would not have solved the issue as he would have measured on his laptop full upload and download speeds.
I'm sure this is going to become a more common issue as home internet speeds start to soar (thank you Google!), so hopefully this helps those with similar issues.
To sum up:
Go to Start->Control Panel->Device Manager->Network adapters->Your adapters name (mine is Atheros AR8152/8158 PCI-E Fast Ethernet Controller (NDIS 6.20), right-click then select Properties. On the Advance tab, find property Large Send Offload (IPv4) and change its value to Disabledthen click OK.
If you have a Large Send Offload (IPv4) v2 try setting that to Enable (with the other one disabled of course).
Hope this helps!
And thank you George.
Tom