Slow Upload

I know this topic has been discussed before, but no conclusion reached. Relatively suddenly, my normal speeds (65/18) with BT FTTC have dropped to 65/0.5 Connection to sites has been erratic, even this site's speed test will take a minute or so to start. Ths problem is only with my ethernet-connected PC - all wireless devices are perfectly fast both ways.
After days of searching forums, fitting new ethernet card, cables, etc, discovered the ruse of disabling the Large Send Offload (LSO) in my Ethernet controller properties.
Bingo ! It did the trick perfectly - everything back to normal. The Wonder Cure !
Only one problem - shut down, restart and you've got to do it all over again. There is no way of making the Disable permanent. At least not for a non-tecchie.
Can anyone shed some light on the real reason, and suggest a way out, please ??

The setting shouldn't reset on a reboot. Not sure how you are setting it but there is a method here that is worth trying.

Thanks Ian. I normally disable via Device Manager - basically end up with the same result. Went your route just now, rebooted and, surprise surprise, it is Enabled again.
There are many posts out there about this, and the only suggestion I have seen involves fiddling with the registry, which I am not willing to try....
There must be a root cause, maybe anti-virus programs causing it (mine is Bitdefender) ?

What NIC is it?

Have you tried deleting it and then reinstalling it? Alternatively see if you can locate a later, native driver rather than the windows default driver.

Is it just a coincidence that the method ian72 suggested is from Bitdefender which is the same AV program that you use? Or.......

Cheers!

Pure coincidence, it was the first useful link I found in Google.

A final follow-up to this saga.Having disconnected the Ethernet, and acquired a wireless card for the PC, things were still problematic.
However I have discovered, by chance, the culprit. My rig has an ASUS motherboard, and I recently upgraded the software (ASUS AI Suite II) to check on overheating/fan problems.
There is, tucked away in that suite a facility called Network iControl, which by default was at ON. It is supposed to provide 'a smoother online experience'.
Switching it off cured everything ! I hope this might assist someone else in the future...

Was that on board (as in on the Asus motherboard) adapter, rather than a discrete NIC in a slot etc?

Onboard. The same bit of software was also presumably responsible for my inability to edit the adapter properties or refresh the driver. All very frustrating.
Considering the number of ASUS boards out there, it is surprising that this issue doesn't seem to be discussed anywhere....

Slightly odd, but perhaps the management software from ASUS isn’t widely installed/used or a particular version is particularly problematic against a windows update. Could be lots of things. Good you got to the bottom of it anyhow.