Did you change the High Precision Event Timer (HPET) to 64 bit and set the AHCI mode instead of IDE in the bios prior to install. That could be cause your boot issues.
Also here is an entire thread dedicated to UD3/6870(50) builds. Its almost 50 pages long and loaded full of good information.
http://www.tonymacx86.com/viewtopic.php?f=168&t=32306
If you decide to re-install to achieve better stability and proper boot times, I'd highly reccomend unibeast/multibeast method. I can gladly help you if you'd like as well. Installing kext files (kernel extentions) and selecting the proper set up files from multibeast isn't hard at all. Feel free to PM me if you need some help an decided to try the install again.
Here are the basics to the install though:
Once done with making Unibeast drive do this:
Set bios to these settings:
1.HPET to 64bit from 32bit
2.All settings that say IDE, change it to AHCI
3.Plug in flash drive, mouse, monitor, keyboard and reboot.
4.Go to boot menu (on the GA-Z68X-UD3H-B3 it is F12)
5.Select USB-HDD and hit enter.
6.If it doesn't boot into the iBoot looking screen try to plug USB drive into other port and 7.hit enter again
8.Choose USB from menu
-OPTIONAL- Go to disk utility and format your HDD/SSD, you may need to do this.
9.Install OSX Like normal
10.Boot from Unibeast Drive again
11. Boot from new OSX install
12.Put
DSDT-x.aml on desktop (free download from tonymacx86)
13.Run MultiBeast with recommended settings by Gordo
14. Reboot and enjoy!
Download these few programs and run them to check for system stablity and proper function. What are your read/write speeds of the SSD?
Uniegine Heaven (there is a mac version)
Nova Bench
Geek Bench
Cinebench