I have 3 Gbps fibre internet connected to my machine, through ethernet, and I never seem to get the full download speed no matter what, however the upload speed is always at maximum, which is weird. The speedtest, in the router always is always 3 Gbps, and averages around 3250 mbit/s download and 3210 mbit/s upload. On my gaming PC, I always get 3200 mbps upload and it never drops, but download speed almost never reaches 3 gbps or above, it averages around 2.6 to 2.8 gbps and can drop to as low as 2.0 gbps sometimes, it keeps changing even when the no application or game is using the internet. I have tried to fix this issue, from changing every setting, to clean installing Windows to changing network adapters. I first had a Marvell AQC-107 10 Gigabit adapter which had the same issue, upload always works well but download speed doesn’t. I’m currently using an Intel X540-T1 10 GB and it’s not much better.
I got support from my ISP, and there is no issue with the router or connection, they updated the router firmware to the latest but that didn’t help either.
I use Windows 11 22H2, latest updates, Ryzen 5800X, Gen 4 SSD. The ethernet adapter is on a PCIe x16 slot on the motherboard. I even installed a fan on it, incase it was thermal throttling the speed.
I have tried network adapter settings too, like disabling Interrupt Moderation and increasing buffers. No matter what I do, the download speed does not stabilize to 3 gbps, which confuses me as upload always is? Both the router and ethernet adapter are set to 10 Gbps Full Duplex.
At this point, all I can think of is my SSD is wearing out, as the write speed is not reaching optimal speeds. It’s supposed to have 4400 mb/s but, the write speed is always 1500-2200 mb/s, while the read speed is 5003 mb/s and is optimal. There seems to be some write speed issue, and maybe replacing the SSD will fix the problem? Or the ethernet wire I’m using is counterfeit, or does not have enough protection and may be under EMI.
Any help is appreciated.
