Re: is it possible gentlemen to replace the whole board with a new generation i7 Motherboard? unfortunately not possible if you want to use the 755 MT case which is BTX and only accommodates BTX motherboard.  the next Optiplex model using 1st and 2nd gen core i7 cpu is 980 or 790 which are both ATX.  the modern intel motherboards are almost all ATX (or proprietary). if you really want to stick with the 755 tower case, you need to cut/mod the chassis into an ATX case or ask some one to help you do that.  people have done this to the XPS 720 case which is BTX and changed it into ATX.  it is labor intensive and not for everyone.
Hello guys, this is my first time to be here, and I got a question about upgrading my MT Tower Dell Optiplex 755 to an i7 CPU Motherboard. So, is it possible gentlemen to replace the whole board with a new generation i7 Motherboard? If so, would you please guide me to an excellent type that would fit in size and operation within my old tower, no matter how much it cost? I have read that I could jump to 9020 or so, but I really want to keep my old tower it looks perfect for me. If possible I will move into 1 TB SSD and get rid of the old HDD. In addition, I'm going to increase the RAM from 4G to 16GB to improve the computer performance, despite my old CPU is 2.66GHz, but it doesn't satisfy my needs. Therefore, would someone of this community computer expert answers my inquiry. Thanks indeed,
Dell Optiplex 755 Mother Board