Network RX Data Rate reduced from 9.5 Gbps to 2.0 Gbps with BDIS


Hi - I have a QNAP NAS file server with a 10 Gbe direct wired connection to my PC. The network connection has static IPv4 addresses on both ends, with no IPv6, DNS, or DHCP enabled. I installed this high speed connection to get the maximum file transfer rates between the two devices.

After installing the 10 Gbe connection, I discovered that I was having an issue where my PC ⇐ NAS RX file transfer rates were slow (about 1.5 Gbps max), while my PC ⇒ NAS TX file transfer rates were fine (about 4 to 6 Gbps).

I started testing with iperf3, and found that my direct network connection speeds were odd: iperf3 showed that my TX bandwidth was 9.5 Gbps, while my RX bandwidth was being limited to 2.0 Gbps.

I had tried a number of debugging steps. For example, when I booted into Ubuntu 22.04 or Windows 11 To Go vis a USB drive, I would see TX / RX bandwidth rates at the expected 9.5 Gbps for both directions. My Windows 11 To Go drive had BitDefender Free installed, so I wasn't focusing on BitDefender as an issue.

I also saw both TX / RX bandwidth rates at 9.5 Gbps if I booted Win11 into "Safe Mode with Networking". So, something in my PC configuration was the culprit.

After a few days of debugging, I finally isolated the issue to BD Internet Security that I had purchased for my PC. Even though (I believe) I had manually disabled all of the BDIS protection features, my RX bandwidth was still reduced down to 2.0 Gbps.

Eventually, I found that the only way that my RX bandwidth would be restored to 9.5 Gbps would be for me to either totally uninstall BD, or to downgrade to BitDefender Free (which I am currently on now).

Is there a way to keep BitDefender Internet Security installed and configure it so that I don't take a hit on the RX network bandwidth for my "No Internet" PC ⇐⇒ NAS connection?



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