See Video Demo at: vimeo.com/155636855
I've grappled with this issue for too long--now I would love some outside help.
* This has nothing to do with VM technology--see added note at end of post *
The attached image contains a side-by-side image of a WordPad file with text representing all letters in the alphabet, lower- and upper-case. The image on the left was taken from a Windows 10 virtual machine (the "guest" OS)running on a Windows 10 host (the "host" OS); the image on the right was taken from the Windows host:
Enlarge the image and take a good look at the differences around the edges of each letter: The left is much smoother than the right--and in case you are tempted to jump to a quick conclusion, CLEARTYPE IS NOT THE ISSUE (see points below), at least not from an "on" versus "off" perspective (in other words, a registry setting related to ClearType might be involved, but nothing on the Windows UI related to ClearType is causing this because both machines are calibrated for ClearType and ClearType is ON on both host and guest machines).
Both OS's are using the same Myriad font TrueType (TTF) font file
Both OS's are set to the same screen resolution.
I thought this was a Windows video-driver issue, but I have the latest nVidia driver and I'm running a relatively high-end GeForce GTX 560 card with DirectX 12 on both host and guest.
Both WordPad files are using the same font, font size, font style, and zoom (100%).
Both Windows 10 OS's are fully updated using Windows Update.
ClearType is active (on) on both the Windows host as well as in the virtual machine. I've tried various combinations of ClearType (turning it off on the host and turning it off on the guest, and all other combinations) and there is no change to the rough-edge artifact displayed on the host compared to the guest.
I am not aware of any DPI differences between the guest and host. Other fonts, such as the Windows-included Arial font, show similar rough-edge issues only on the host--I just chose Myriad Pro to illustrate the problem.
The color of both fonts is 100% BLACK (#000).
This issue appears in ALL applications that can render TrueType fonts. I used WordPad just as an example, but it happens in Microsoft PowerPoint and TechSmith's Camtasia as well.
This issue is not related to TrueType fonts; it happens for OTF fonts as well.
And, for what it's worth, it doesn't matter if I view the host from another computer through a remote-desktop session (RDP) or using something like TeamViewer; also, the behavior of the guest doesn't change when I use RDP or TeamViewer.
Clearly something is awry with the font-rendering subsystem on the host. Interestingly, the host was a Windows 7 Ultimate machine until about a week ago (early Feb 2016), when I upgraded it by installing Windows 10 Enterprise. I had hoped that doing such an upgrade from Windows 7 to Windows 10 would fix the font-rendering issue especially because I already saw that Windows 10 running in a virtual machine on the same host did not have the font-rendering issue. Unfortunately, the update to Windows 10 did not fix the font-rendering (I did not do a fresh Windows 10 install--I did the update that preserves the previous OS files and settings).
Due to everything I wrote above, I suspect there is some corrupted, missing, or incorrect value in the registry related to font-rendering for the host OS--but what could that be?
* Added 2/12/2016 * I took a brand-new hard drive and installed a clean Windows 10 instance onto the same hardware on which the "host" I refer to above is running. The new Windows 10 instance has smooth fonts, just like the virtual machine (VM) instance of Windows 10. This tells me that the hardware of the machine is not causing the problem to generate the image on the right and that the VM (or virtualization technology) is not the reason for the disparity. I now have hard drive A with Windows 10 on a physical machine I can boot into and see the image on the right; I have a second hard drive B with Windows 10 on the same machine I can boot into to show the image on the left.
I then wiped that new hard drive and installed Windows 7 Ultimate from Microsoft source Setup DVD. It also renders the image at the LEFT (the correct, smooth fonts). So the problem is not that Windows 7 has the issue on my hardware and that Windows 10 doesn't correct it--it's clear to me now that Windows 7 does not show the font issue on my hardware if I reinstall Windows 7.
So, virtualization aside--it appears that I am witnessing some sort of corruption in the font-rendering subsystem between my existing host machine and a "normal" Windows 7/10 machine (remember, my existing host machine was upgraded from Windows 7 Ultimate to Windows 10 Enterprise and the problem did exist in Windows 7 Ultimate before I did the upgrade; in fact, I was hoping the upgrade would fix this issue--alas, it did not).
I will try to look/compare key registry entries for disparities in my free time but I'm still eager to hear from any experts who might help me zero-in on the root cause.