What I didn't know at the time (because it's my husband who usually uses that machine) is that this VM has been frustratingly slow for quite a while. So of course because he was sure that something I'd done had caused MORE problems, my hubby started to complain. And he was right: performance wasn't as bad as it had been on the SSD, but it was definitely not good. So I went on a broader search for solutions, tried the usual suggestions from this forum, and investigated pretty much every setting in the VM. It took a fair amount of time and effort, but I definitely improved performance on the old drive. And today I made one final tweak and voila! My Win10 VM is running beautifully on the new SSD.
Since I found bits and pieces of useful info in various places, I thought it might be valuable to the many others who seem to be having similar problems to summarize all of the things I did in one place. So here's the list:
1. Shut down your VM and check the settings under System/Motherboard. I saw suggestions that only 4GB of memory was needed, but 6 or 8 seems to work much better. I have 16, so left it at 8MB after trying 4 to see if that would improve host machine performance. All that did was make the VM fail, so I went back to 8.
2. Click on the Processor tab. I had only one processor assigned to the VM, but some recommendations I saw suggested that Win10 likes to have at least two. Suggestions say to give the VM half of whatever you've got for optimal performance. I gave mine two.
3. On that same tab, set the execution cap to 100%. This was a suggestion from somewhere out in the forums or maybe on the web. Mine already was, so I can't say how much that helps.
4. Under Extended Features, make sure PAE/NX is enabled. This suggestion I got from reading the VirtualBox manual. Mine was already set, but now I understand why
5. On the Acceleration tab, enable the Hyper-V paravirtualization interface. There were hints about this here and there, but it wasn't until I checked the VirtualBox manual to figure out what the heck this parameter was about that I realized that "Legacy" was probably not a good setting. The VirtualBox documentation suggests Hyper-V for Windows guests. This had more of an impact on performance than pretty much anything else I tried. Also make sure Nested Paging is enabled. Mine already was, so I can't say how much that helps.
6. Click on "Storage" and then on your primary drive. If you're running on an SSD, make sure that SSD box is checked. There's a parameter to set in the VM and on the host too -- more on that later. This was the final tweak that made my guest work properly on the SSD -- before that it was still slower than on the old drive even with all the other tweaks. I didn't find this in the manual or anywhere in the forum, just happened to notice it when I was combing through all of the settings.
7. Since we're on storage I'll mention that I did see some suggestions to make the system drive fixed rather than dynamically allocated to improve performance, but I haven't tried that yet and probably won't because performance is now fine. If anyone tests it I'd love to hear whether it's worth the trouble.
8. Make sure TRIM is enabled for your host machine if your SSD supports TRIM. If you're running on a Mac, here's the article I used to figure it all out: https://www.howtogeek.com/222077/how-to ... -mac-os-x/ Mine was not enabled (since I added the drive myself and the original was not SSD), so I did.
9. Start up your VM. Install the appropriate version of Guest Additions if you haven't already done so. Hopefully everyone knows to do this, but I did see a whole lot of people posting for help who did not, so maybe this isn't obvious.
10. Enable TRIM on your Win10 guest. Instructions on how to check if it's already enabled and enable it if it isn't are here: https://www.howtogeek.com/257196/how-to ... f-it-isnt/. Mine wasn't, so I did.
That's it! Hopefully if you're as frustrated as I was by Win10 performance under VirtualBox on a Mac you'll find the things to change to make you as happy as I am.
Cindy Harris
Pittsburgh, PA
VirtualBox 6.0.2
OSX Mojave 10.14.2 host, Win10 guest, Mac min 2012, 16MB w/ OEM SSD