Question super slow uploads only 1 PC


Nov 8, 2016
Small Business network . I have 1 pc that has normal download speeds 90-100 mbps and basically no upload speeds at all .023 Mbps . I have tried everything including using a different Cat5 cable from a PC that has normal upload speeds . So i know for sure its not the network . Its something specific to this PC . I flushed DNS , Reset the IP , changed the adapter setting from automatically picking the Domain server and IP address to me setting them . Still nothing .

Can the NIC be causing bad upload speeds ... I dont know what else it .. I tried everything else .. the troubleshooter doesn't find anything wrong . i went as far as to run a cat from from a switch through the office directly to the NIC .

Any ideas will be greatly appreciated .


If you have a system image in place or availability to do a clean install I think that is where I would start, however I am not a networking wizard that would be able to tell you other aspects to be looking for. It seems unlikely to me that if you are using a completely different PC and cable to the location/troubled PC and the issue isn't following it would seem localized to that specific machine.


Nov 8, 2016
Well incase anyone is interested the issue is the N.I.C . I ordered a USB to Ethernet Adapter and just like magic the upload speeds are back to normal .

I have updated drivers on the N.I.C ,uninstalled and reinstalled so my guess is its something Hardware related not Software of course I don't know for sure .

The big Question now is do I just leave the USB to ethernet installed and consider this case closed or do I keep digging and banging my head on the keyboard .

I havent decided just yet . Now that the problem is solved if this gives anyone a new idea of what the root issue may be please share .

As always thanks for all the great info …


Nov 8, 2016
So since i first posted this i have had 2 more workstations within the network do the same thing . Download speed is super fast upload speed is super slow. My first hint is the users complaining about emails in there OUTBOX.

I scanned for viruses ,malware and such . Since now it seems like its spreading . Each PC comes back clean .
Its seems like its 1 computer each month . First in FEB then March now April .

The N.I.C.s show to be working proper when i check on device manager. I also update the drivers just in case since we do have some older Pc ON SITE . There all Windows 10 pro . Could this be the updates causing this as a push to move to windows 11.

Anyway once i switch it over to a USB N.I.C everything works correctly . I would really like to find the really problem because switching to a USB N.I.C is really just a Band-Aid on a bullet hole .

Anyone seeing this issue?

Thanks again for any insight .


How many devices in the Small Business network? What sort of devices: computers, printers, storage (NAS), mobile?

Mix of wired and wireless?

Make and model: modem, router (or modem /router if combined)?

The Router's logs, if available and enabled, may provide some clue.

Also check the router's configuration pages for allowed number of network devices, assigned IP addresses (dynamic and static), connected devices, MACs, restrictions, QoS, and similar configuration settings that impact individual systems on the router's network,

DHCP environment? Any Static IP's?

= = = =

Take a look at Task Manager, Resource Monitor, and Process Explorer on the slow upload systems.

Note: Process Explorer. Microsoft, free.

The objective being to determine what resources are being used, to what extent (%), and what is using any given resource.

Use all three tools but only one tool at a time. Compare a fast upload to a slow upload PC to look for differences.

Run the tools while not uploading to get a baseline understanding of the test/slow upload PC. Then, leaving the tool window open and viewable, do some uploads as usual.

Again watch for changes.

And take a look at a slow upload PC before (if possible) using the USB NIC. Do that before (USB NIC not installed/ PC slow upload) and after (NIC installed, upload speeds okay) comparison.

I would also start comparing the results of "ipconfig /all" and "arp -a" for slow and fast upload systems. Do the same when the computer is slow and then again when fast.

Keep track of IP addresses assigned to each network device. Look for conflicts or some other IP address error.

Sketch out a network diagram showing all devices, IP addresses, MACs, and so forth. Map out how the problem is moving about and look at the diagram. May be some clue therein.

See what you can find.

Be methodical, keep notes, use the diagram. If you have not already done so then write down as much history as you can remember.

Key is to discover what is different (or becomes different) about any PC that starts having slow uploads. And becomes via whatever means, a fast upload PC again.

My thought is a IP address conflict of some kind. Possibly related to a DHCP IP address that would be moving around amongst PCs on a network. Sooner or later comes into a conflict again.