Windows Guest Very Slow Network File Transfers v7.0.12

[sai-mike]

I have two Windows 7 Guests running on a Debian 12 Desktop PC.
After upgrading to VirtualBox 7, I am experiencing very slow file transfers from the Guests to a NAS.
No issues running these VMs on v6.1.x

Host:
Architecture: x86_64
Intel NUC: 13th Gen Intel(R) Core(TM) i5-1340P
Virtualization: VT-x
RAM: 16 GB
O/S: Debian GNU/Linux 12 (bookworm)
Kernel: Linux 6.1.0-13-amd64
Extension Pack: v7.0.12r159484
VirtualBox v7.0.12 r159484 (Qt5.15.8)

Guests:
Windows 7 64-bit
Base Memory: 4 GB
Processors: 2 CPUs
One Network Adapter in Bridged Mode
Guest Additions v7.0.13 r160164

Both Guests were running GA v7.0.10 because of the bug in GA v7.0.12 with Win7 and experiencing the issue.
When GA v7.0.13 was released, I upgraded to that version and still have the same problem.

Initially both Guests were using a Intel PRO/1000 MT Desktop Adapter.

I ran DiskBench.exe on both Guests and had similar results - attempting to copy a 50 MB file from the Guest to a folder on the NAS resulted in only 3.8 MB copied after 4 hours.

I copied the same file from the Host to the same NAS folder in 0.48 seconds:
50331648 bytes (50 MB, 48 MiB) copied, 0.482932 s, 104 MB/s
Copying the file from the NAS to the Host produced a similar result:
50331648 bytes (50 MB, 48 MiB) copied, 0.441563 s, 114 MB/s

So, I upgraded one of the two Guests from the Intel Adapter to a Paravirtualized Network Adapter. This was a huge improvement, but still far below the Host transfer speed:
Created file: S:\DiskBench1.bin
Size: 50331648 bytes
Time: 18926 ms
Transfer Rate: 2.536 MB/s

Read file: S:\DiskBench1.bin
Size: 50331648 bytes
Time: 112157 ms
Transfer Rate: 0.428 MB/s

The read speed with the paravirtualized adapter is also much slower than the write speed.

Both Guests are using a Mapped Network Drive to connect to the NAS folder.
The Host is using a cifs mount to connect to the same folder on the NAS.

One Guest Log attached.

Do I need to make some kind of Guest configuration change when moving from VBox v6 to v7?

[sai-mike]

I just verified that I have the same issue with a Win10 Guest using a Intel PRO/1000 MT Desktop Adapter, so I changed the title. The Win10 Guest is running GA v7.0.12 r159484.

[fth0]

I don't know if it plays a role here, but since you're using a 13th Gen Intel CPU, is the VirtualBoxVM process running on the P-cores or the E-cores?

[sai-mike]

Looks like this was sorted out by the Linux kernel back in v5.18 in 2022:

"The upcoming Linux version 5.18 will improve the performance of Intel's latest 12th Generation Core 'Alder Lake' processors, as it will come with the company's new drivers that optimize usage of (P)erformance and (E)fficiency cores. These CPUs rank as many of the best CPUs for gaming and other tasks, but at present, they work best on Windows 11 PCs, which is typically unheard of when compared to performance in Linux."

https://www.tomshardware.com/news/intel ... linux-5-18

[sai-mike]

I did an advanced search this morning across all forums for: Searched query: +slow +network
It came up with numerous issues related to very slow network transfer speeds with VBox v7.0.x going back to June.

These seem to occur with many different Host and Guest operating systems. Some issues are for LAN connections and some are for WAN connections. The common issue I see is that it occurs with VBox bridged adapters and Intel physical adapters on the Host.

One of the posts said the problem disappeared when using a NAT adapter instead of a Bridged Adapter. So I tried that with the previous Intel PRO/1000 MT Desktop adapter type, and my file write performance increased to 2.5 MB/s or approx the same as my test using a paravirtualized adapter type. In that test (paravirtualized driver + bridged mode) however, read performance was still abysmal at 0.428 MB/s. With the NAT adapter, the read performance was the same as the Host performance at 114 MB/s.

So my VMs are now usable under v7.0.12 even though the write performance is still lousy.

[fth0]

FWIW, googling for only "enp86s0" revealed several hits on the Proxmox forums with different networking issues. Perhaps you can get additional ideas from there. For example, you could check the output of "ethtool enp86s0".