Fusion Internet Speed is Super Slow compared to Host

[SAPSULTANT]

Hello

I am new to the forums but a long time fusion user. Until recently internet speed was not an issue but I am seeing a huge loss of internet performance.

- Running an Early 2015 MBP with MAC OS Catalina with Fusion 11.5.6

- VMware Tools 11.1.0 Build 16036546

- Windows 10 all updated

The host machine (MAC OS) side gets upward of 643MB download speeds using the speed test however when I do a similar test on the Windows I never exceed 55MB. I have cycled through using the various network connections NAT, Bridge, Autodetect

I even went into  gpedit.msc >> Administrative Templates >> Network >> QoS Packet Scheduler >> Limit Reserve Bandwidth set to Enable and 100 and switched to 0.

I have endlessly tired various things.

Any help will be greatly appreciated in solving this. Happy to share any additional information if you give me the instructions to generate the relevant logs.

[wila]

Hi,

Changing to UEFI is something you can do, I'm not really expecting it to make much of a difference though.

As before... make sure you have good backup.

Then for changing the disk from MBR to GPT follow these steps:

https://www.windowscentral.com/how-convert-mbr-disk-gpt-move-bios-uefi-windows-10

After that you have to change the VM configuration to use UEFI instead of BIOS and you can do that via the menu.

With your VM shut down, go to settings, advanced, Firmware type:

Change it from Legacy BIOS to UEFI

Do not make other changes in regards to UEFI and VBS in that screen.

--

Wil

[wila]

Oh.. one other thing that also might impact your performance. I noticed you had AutoProtect snapshots enabled and as such your VM always has snapshots open.

This degrades your disk read/write performance.

Depending on how you tested your internet speed -- if it is download to disk -- then your performance test might actually have been testing your disk write speed instead of the network speed.

--

Wil

[SAPSULTANT]

Wila I made all these changes, not much of an improvement that I notice.

The part I don't understand is why in Ubuntu the internet is super fast and under Windows is super shitty. Is this just due to the bloat windows has? What if I did a fresh install of windows 10?

[wila]

Hi,

Let's get back to basics.

When you say:

The part I don't understand is why in Ubuntu the internet is super fast and under Windows is super shitty.

How are you testing your internet speed?

--

Wil

[SAPSULTANT]

Im not doing a sophisticated test by any sorts. Im just running a speed test Ookla or Google.

I have tried using the new Edge Browser and Chrome.  I did a similar test in Ubuntu but it had the FireFox browser installed which I used. wila​

[wila]

Hi,

The browser used should not make a big difference for this test. If anything I would have expected Chrome and Edge to be slightly faster than Firefox.

The tests you ran are fine.

Ookla and Google speed tests should indeed measure bandwidth and not be ending up misrepresenting bandwidth due to other factors such as disk writing speed or a bad DNS server or a bad route or...

That also eliminates a few other uncertainties and I'm not sure why you would get better bandwidth in Linux than in Windows 10.

I'm having doubts that a re-install from scratch is going to fix it or that you can fix it in another way.

Perhaps someone else has another idea.

--

Wil

[SAPSULTANT]

Thanks for your helo wila​ I actually noticed some improvements opening Excel and Word with the changes.

Mikero​ any ideas for this issue other than what we tried?

[XStylus-BZ]

By any chance are you on a 10GbE network adapter on your workstation?

I was experiencing similar circumstances as yours. When my workstation is connected via 10GbE (using a Intel X540 network adapter), downlink throughput would be pathetic, though uplink throughput would be satisfactory.

However, when I switched to the onboard 1GbE network adapters, downlink and uplink throughput became satisfactory.

[iamurph]

IM having the same issue. My host MacBook is running at 300Mb per sec and my guest (kali) is at less than 1mb per second. 

[iamurph]

The solution I found was not only was I have ing very slow guest connection i was also having issues whith sha256 checksum and library keys not being valid. Which I realized it to be a router issues. If you got to your router and reboot it with your vM logged off when you restart the van all is good. And you should see a immediate improvement of speed. And if my case not dropping time sensitive packets  dealing with ssh and key encryption. Also maybe check to see if your guest is showing up in the setting and also not blocked or throttled. Hope this helps. 

[iamurph]

I was suffering the same issue and was having 300% lower speeds on my host vm. There was also some issues when working on my kali machine that gave me sha25 and Key mismatch.. long story short it was my router cause ing the damage. Fir me when I logged on the router I saw my guest machine had a IP issues from my dhcp on my router but it said it was offline when it was. The firewall itself wasn’t blocking anything but after rebooting, not resetting my modem all went back to fine. I think the routers get theown sometime with the vm,s connection through the same NIC. 

Hope  this helps. 

[zaybon]

Same here! The moment I changed from my 10GbE to 1 GbE network speeds where satisfactory. It was driving me nuts, it was the same even in Parallels. Thanks Xstylus-BZ.

[vaxman]

This is an old thread and I see the more recent posts attribute this to a router external to the Fusion host becoming confused by the appearance of multiple Ethernet MAC addresses (or IPs) on the same port (due to the host and VMs sharing the same NIC using Bridged networking via Apple’s vmnet.framework under Fusion). It sounds like some kind of ARP issue. Do want to add that in limited testing, it seems to be crucial that flow-control be turned on in the NIC’s Hardware panel of the Mac’s Settings dialog. On Intel using built-in GbE ports under macOS 12.6.3 and Fusion 13.0, this seems to completely resolve VM’s upload speed issue and makes the VM’s download speed faster and more consistent, though still 75% below what can be seen in host-based downloads (even when the VM is using vmxnet3, host and guest firewalls are disabled, large RAM and CPU allocations, unloaded host system, trying multiple cables, NICs and ports as well as under Win11 and Linux kernel 6.x based VMs).. 

[gringley]

The other aspect here is that it's a MBP so the host network is WiFi.  WiFi in Fusion and macOS 11 and beyond is generally iffy in my experience.  On my M1 MacBook I did an experiment where I hooked my Thunderbolt 3-2 adapter, then my Thunderbolt to Gigabit Ethernet adapter (both the original Apple adapters to see if they worked with M1) and got better networking results than with the WiFi.

[vaxman]

Not using WiFi (adapter disabled) and have same results using either of the built-in Ethernet ports or a TB-to-Ethernet adapter. I have been able to obtain consistent maximum UPLOAD performance from the Linux or Windows11 VM by ensuring that hardware flow-control is enabled on the port in the host macOS Settings, but DOWNLOAD performance to the Linux or Windows11 VM remains a fraction of capacity. I believe there is some kind of problem with the code that exchanges packets between user mode and Apple's kernel mode vmnet driver in a suboptimal way. I've also confirmed there are definite bugs in Apple's ARP handling in Apple's kernel mode vmnet driver. Several times I have lost connectivity after making changes inside the VM and had no way to restore except to Power Off all VMs, Quit the Fusion 13 app and then reboot the host Mac and then observe the problem completely cleared simply by launching Fusion 13 and Startup those same VMs.