Update - If anyone needs to change a MB in their XPS studio 8300 not unlocked I7 2600. The MSI B75MA works great. Installed mine last night along with SSD and new WDC green 1tb HDD having no problems with it.
However, I will mention I did not have a place to connect my front USB connections So I am unable to use them. Honestly not a big deal for me. I never really used them anyways.