On a fresh full installation of Windows 8 Pro 64-bit + our programs, the hard drive has 33GB of used space.  If I run Windows 7 File Recovery: Create a system image, and save the image on a USB hard drive, the VHDX format image size is 21GB.

But if I repeat the process and create the system image on DVD+R discs, it only requires (2) full DVD's + a 12MB VHDX on DVD #3.

So 21GB on hard drive vs. about 9GB on DVD.

I saw another thread somewhere noting the same kind of huge disparity, but no explanation was posted.

I have so far found no documentation that provides a hint of explanation for this.  Does anyone here know?

Hi,

There is no document about this situation. You can open both system images to compare the difference.