Random slowness in server and VM in Asrock

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We have a Windows Server 2019 host running Hyper-V, hosting a Windows 10 virtual machine (VM) with SQL installed in it. We observed that this VM experiences random slowness specifically during file copy operations and SQL activities such as select queries. The host server has 2x10G LAN ports. One port is shared with the VM using Virtual Switch and another port is dedicated with host server. Effectively, 2 ports are used by host server with different subnet range We conducted network speed tests using iPerf, and the results indicate that outgoing transfer speeds are effectively zero in the following scenarios:

From the VM to outside the VM
From the Host to outside the Host
This behavior is consistent across both network adapters on the host machine. However, there is no issue when:

Copying data between drives within the VM

Copying data from other PCs on the network to the VM or Host (Incoming traffic)

Event Logs & IntelDCB Warning

In the Event Viewer, we frequently see the Application Event ID 791 logged for IntelDCB, with the message: "Application feature on a device has changed to non-operational." We referred to the Intel datasheet corresponding to our Ethernet controller and noted that IntelDCB is responsible for ensuring that network packets are transmitted reliably and without loss. However, we're uncertain about the exact corrective steps.

Online Research & Attempted Fixes

Our research suggests the issue could be related to: Virtual switch misconfiguration Antivirus or firewall interference Corrupted NIC drivers Offloading settings

Virtual Machine Queue (VMQ) settings : As per this forum post, it refers to VMQ solving the issue. We tried disabling and re-enabling VMQ, but the issue persists. Additionally, CPU and memory usage on both the host and VM are within acceptable limits.

We are looking to understand: What could be the root cause of zero outgoing packet transfers in this setup? And what troubleshooting or configuration changes might resolve it?

Troubleshooting Steps Tried Connected one network port dedicated to VM Interchanged the adapters with VM Changed network cables, ports in network switch etc. Verified VMQ settings Tested with different antivirus/firewall settings Checked with latest NIC drivers Reset & configuring the virtual switch Re-enabled RSC and later disabled

iPerf Results Summary

Test 1: Host ??VM (Outgoing from host to VM) Connecting to host xxx, port xx
[ 4] local xxxx port xxx connected to xxx port xxx
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-10.00 sec 693 MBytes 582 Mbits/sec sender
[ 4] 0.00-10.00 sec 693 MBytes 582 Mbits/sec receiver

Test 2: VM ??Host (Outgoing from VM to host) Connecting to host xxx, port xx
[ 5] local xxxx port xxx connected to xxx port xxx
[ 5] 0.00-10.01 sec 0.00 Bytes 0.00 bits/sec sender
[ 5] 0.00-10.01 sec 3.90 GBytes 3.35 Gbits/sec receiver

Hardware Specifications

Host OS: Windows Server 2019

VM OS: Windows 10 with SQL Server Standard 2017

Antivirus Detalils: Sentinelone Singularity Control

Motherboard: ASRock ROME2D16-2T (Rack)

Processor: AMD EPYC 7373X ??16 Cores / 32 Threads, 3.05/3.80GHz, 768MB L3 Cache

Ethernet: Intel® X550-AT2 ??2? 10GbE RJ45 Ports

NICs: 2 physical network adapters

RAID Controller: LSI MegaRAID 9271-4i SGL SATA+SAS (LSI00328)

Disk Drives: WD Blue SN5000 NVMe SSD ??500GB, up to 5000 MB/s

Samsung PM893 Enterprise SATA SSD ??480GB, up to 550 MB/s

WD Red SA500 NAS SATA SSD ??2TB, up to 560 MB/s

We would appreciate any suggestions or insights from the community regarding potential causes or resolution steps. Thanks in advance.