2.5G NIC slow transfert speeds

I have an ASRock Z390 Phantom Gaming 9 and a Gaming 6.

On both the PCs, with the 2.5G LAN drivers installed I am getting speeds for 40-50MB/s transferring files TO my server. Files are being transferred to Samsung 970 Pro 1TB.

The PCs are connected to Netgear MS510TX switches on the 5G ports. I've also tried the 2.5G and 10G ports on the switch but the speeds are the same.

Tried copying 6 x 1.5GB files, 1 x 10GB file, 1 x 20GB file.

Are there some settings I need to change for the NIC?

I notice the NIC doesn't support Receive Segment Coalescing (RSC), so that's not the cause. I've also tested with Spanning Tree Protocol (STP) enabled and disabled on the switch.

The ASRock boards PCs are running Windows 10 1809. The server is running Windows 2012 R2. CPUs are 9600K and 9700K respectively.

thanks

badbri wrote: That is a little slow, what is the source of the files ? Is it standard SATA HD/SDD, M2 SSD or other ? Double check the cables and make sure they are CAT6a or better on all routes.

Cables are new quality LSZH Cat6A cables, lengths typically 2m-3m between PC and switch. Switch to Switch is fiber optic. Transfer speeds are the same for HDD to HDD, NVMe to NVme. I have no SATA SSDs.

Unplugged and replugged cables. Rebooted PCs and switches.

There are PCs on 10G and they transfer at up to 1000MB/s. Other PCs on 5G transfer at up to 400MB/s. It's only the ASRock boards with the on-board NICs that are having issues.

badbri wrote: Have you tried using the Intel Gigabit LAN on either board ? Just to see if there is an issue not related to the Realtek dragon rtl8125 2.5Gb LAN. You should hit speeds in the 125MB range if they work ok and there is not another issue slowing everything down. Just a thought.

Typical gigabit transfer speeds are between 113 - 117 MB/s sustained in either direction.