Question Different download speeds on two different systems ?

Feb 12, 2025
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Hello, I am currently having some interesting issues regarding download speeds on my computer. I originally built my current PC in 2022 and the entire time I've had it, I have had issues with download speeds regardless of WIFI or ethernet connection. I pay for gigabit internet yet when I download apps/games I usually saw a max of 100mbps. I tried updating drivers, chipsets, BIOS and never ended up finding a solution. I had the issue before and after I upgraded to windows 11. Fast forward to today, I decided to upgrade my computer and installed a new motherboard, CPU, ram etc. I installed the new hardware and sure enough I had the same download speeds.

Where it gets interesting is that I used the old hardware to build my wife a computer and when I went to download a game on steam for her, the download speed shot up to 500mbps. The only difference in hardware was a new Samsung SSD and graphics card compared to what I had mediocre download speeds with. How with essentially the same hardware does the new computer have such drastic differences in speed? I have checked the health of my current SSD and the read and write speeds are all up to par with what they should be. I have tried troubleshooting myself and can't seem to find a solution. If anyone has any ideas or suggestions on what could be going on I would really appreciate the help.
 
I suspect having issues with the wifi also may have gotten you off the troubleshooting path.

Since it is 2 different motherboards and even more that the old motherboard now works correctly I would suspect a bad cable. It is extremely common when you see speeds limited to just under 100mbps for the problem to be a cable.

It could have been a cable say between the modem and the router that would slow down wifi also. Since it works on another machine it is much more likely it is the cable between your current machine and the router. This might be more complex if you are using cables that run through the walls of your house.

There is some screen that microsoft keeps moving around that shows the ethernet port status that shows the speed. I suspect it will say 100/100.

It does not take much for cable to go bad. Could be it fits loosely in the jack or some wire inside the plug has detached. Luckily new cables are a cheap thing to try. Be careful there is a massive amount of fake cable sold. You need nothing real special just cat5e but it must be pure copper with wire size 22-24. The main fake cable to avoid are those flat cables that have wire that is much too thin to meet the certification standards to be a actual ethernet cable.
 
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I suspect having issues with the wifi also may have gotten you off the troubleshooting path.

Since it is 2 different motherboards and even more that the old motherboard now works correctly I would suspect a bad cable. It is extremely common when you see speeds limited to just under 100mbps for the problem to be a cable.

It could have been a cable say between the modem and the router that would slow down wifi also. Since it works on another machine it is much more likely it is the cable between your current machine and the router. This might be more complex if you are using cables that run through the walls of your house.

There is some screen that microsoft keeps moving around that shows the ethernet port status that shows the speed. I suspect it will say 100/100.

It does not take much for cable to go bad. Could be it fits loosely in the jack or some wire inside the plug has detached. Luckily new cables are a cheap thing to try. Be careful there is a massive amount of fake cable sold. You need nothing real special just cat5e but it must be pure copper with wire size 22-24. The main fake cable to avoid are those flat cables that have wire that is much too thin to meet the certification standards to be a actual ethernet cable.
I didn't specify enough in the post but I was getting the same slow download speed on wifi and with an ethernet cable. When I swapped the hardware over the computer had the higher download speed over wifi.
 
Most likely cable or LAN ports (on motherboard, switch or router) issue

router brand/model and motherboard LAN chipset brand/model?
The router is a Calix Gigaspire blast and the new motherboard is a Gigabyte x870 with the Realtek 2.5GBE LAN Chip. Do you think it's possible there's something configured wrong with the windows install on my os drive? The only meaningful difference between my wife's pc and mine before the hardware change is she has a fresh windows 11 install on a new drive.
 
3 immediate thoughts:

Are you certain that only one network adapter (either wired or wireless) is enabled on the computers in question? Not two adapters

Verify that Speed & Duplex are configured as "Auto Negotiate"

Disable IPv6

[Editing to add]

Both computers:

Run "ipconfig /all" (without quotes) via the Command Prompt.

You should be able to copy and paste the full results here with no need to retype everything.
 
3 immediate thoughts:

Are you certain that only one network adapter (either wired or wireless) is enabled on the computers in question? Not two adapters

Verify that Speed & Duplex are configured as "Auto Negotiate"

Disable IPv6

[Editing to add]

Run "ipconfig /all" (without quotes) via the Command Prompt.

You should be able to copy and paste the full results here with no need to retype everything.
I did not change any settings on the old Am4 motherboard before I swapped it into my wife's computer. After a fresh install of windows on the new drive the old hardware shot up to the higher speeds. I will send the ipconfig information when I get the chance after work.
 
Are you sure you are reading the correct way? Steam usually displays the speed download in MB/s, not Mbps, so in that case you have to multiply by 8 to see if you get close to your 1Gbps max speed. You can also go to speedtest.net to see what you really get.

If you really max out at 100Mbps, it's usually a cable problem. How is your wife's computer connected? Wifi or cable? Do you have an internet switch somewhere? A diagram of your home network would be helpful here (cable and wifi connections).

If you really want to rule out the drive from the equation, put some big files (like a movie) to a SSD external drive and copy them to your computer through a USB 3.2 port on your x870. You should get much more than 100Mbps (again, be careful with the units).

You can also install the Speedtest app on your phone and test your wifi speed. May not be super helpful if you also get the problem with an ethernet (cable) connection but at least you can make sure the modem->cable->wifi router circuit is working properly.
 
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Are you sure you are reading the correct way? Steam usually displays the speed download in MB/s, not Mbps, so in that case you have to multiply by 8 to see if you get close to your 1Gbps max speed. You can also go to speedtest.net to see what you really get.

If you really max out at 100Mbps, it's usually a cable problem. How is your wife's computer connected? Wifi or cable? Do you have an internet switch somewhere? A diagram of your home network would be helpful here (cable and wifi connections).

If you really want to rule out the drive from the equation, put some big files (like a movie) to a SSD external drive and copy them to your computer through a USB 3.2 port on your x870. You should get much more than 100Mbps (again, be careful with the units).

You can also install the Speedtest app on your phone and test your wifi speed. May not be super helpful if you also get the problem with an ethernet (cable) connection but at least you can make sure the modem->cable->wifi router circuit is working properly.
Yep. I made sure it was showing the correct way on steam. I was always getting a max 100mbps and when I installed the same hardware on hers I got 500+. I was getting the same numbers on both computers with wifi and ethernet.

All I have setup for internet is one router and I was running the ethernet directly off the router so there's no problems with cables in the walls.

I tested both computers with an internet speed test and got the same numbers with about 700-800 upload and download speed. Same when I test it on my cellphone.

I have my OS installed on a SATA samsung 850 evo. Would that drive effect download speeds even if I am downloading directly to my nvme 980 pro?
 
I tested both computers with an internet speed test and got the same numbers with about 700-800 upload and download speed. Same when I test it on my cellphone.

So, if I understand well, you get 800 Mbps over your WiFi for all the devices with Speedtest, but when you download actual data (on WiFi) you top at 100 Mbps with your PC? Looks like a drive issue indeed. Strange coincidence that it happens to be 100 Mbps though. There is just a way make sure and it's to test the drive.

I have my OS installed on a SATA samsung 850 evo. Would that drive effect download speeds even if I am downloading directly to my nvme 980 pro?
I don't think so. The data doesn't have to go through the system drive to reach you storage drive and the Samsung 850 evo can write up to 520 MB/s anyway so it should not slow you down. If you transfer large files from your SATA to your NVMe what speed do you get? Or did you even try to download a game to your SATA drive just for a test? It's easy to do with Steam just create a new install Steam folder on your C. I have 3 of those on my PC. Just install a random game on your C, check the speed, and uninstall it when it's done.