Ok my story.
I got two 840 EVO's One for home PC, one for music PC. I did read the instructions. And I cloned my sys drive to the SSD per Samsung instructions. But it wouldn't boot. Repeated steps several times to make sure I was doing this right. Still wouldn't boot.
So I created an disk image with Acronis. Then I did a clean install of Win8. Tried to install Acronis on new OS and it wouldn't install.
Went to Acronis for support. Chose live chat support. That was a big disappointment. To solve my Acronis issue, their support gave me a link to a third party site that they told me to let it install a utility that would fix my problem, and they suggested that I let the program run a scan on my registry, and they also said that the first 15 fixes were free!!
I was stunned. Since I have used Acronis for so long, and trusted them, I let the utility install before I was told about the registry scan and free fixes. Acronis went down quite a few notches in my book.
As if it wasn't bad enough, it got worse. I got the Win8 update for $40 way back before release. And I did a clean install of the OS,and wiped everything from my sys drive to do the clean install. Now WIN8 Update won't activate because there was no previous Windows installed.
So, I used a Acronis boot disk to access my backed up image. The restore was successful. But it wouldn't boot into it. Dead in the water.
So I had to go buy another copy of Win8. And I have been working in this issue since the end of May!
My first SSD experience was not good. I just got the os going the day before I had to leave to go out of town for two weeks on business! So I haven't really had time to test.
As to why it happened, I can only guess that it has something to do with Win8 boot manager.
[edit] I didn't even try to put the other SSD in my music computer. I have to learn what I did wrong on my home box before I even attempt to install it on my music PC. [/edit]