Trying to find a replacement motherboard for a late 2012 X51. Part number is OKM92T and it has a LGA 1155 CPU socket. Found similar newer motherboards on-line with same part number, they look identical but descriptions list them having an LGA 1156 CPU socket. Did they change the X51 R1 motherboard CPU socket after 2012? Any information would be helpful as I'm trying to retain the I-7 CPU I currently have and I need the correct socket type. Thanks.