Hi, the bios version had been updated to F4KT61A when it ran with the old CPU. I am not sure is it necessary but the quad core CPU function well in this version of bios and this version should be the latest one. The bios firmware and update tool are still available on Lenovo official website as follows: support.lenovo.com/hk/en/downloads/ds029184-flash-bios-update-thinkcentre-m72e-tiny
i7-3770s has better performance than 3770t but consumes more power. I think it's quite risky if the power supply is only 65W as TDP of 3770s is 65W... It might be a good try if you have a 90W psu