One thing to be aware of is that the actual "effective" top tube length on my Giant defy M/L is ~54cm. (I have one and have measured it.) though Giant lists the top tube as 56.5. If the TCR's measurements are similarly proportioned, and given that they are both compact geometry with slanting top tubes, the frames might actually be about the same size, and part of your issue may be that the 90mm stem is making the reach way too short for you compared to the CAAD with a 120 stem. I'm 5'9", and I ride a Defy M/L with a 90 stem though, granted, I have monkey arms, so it doesn't make a lot of sense we should ride the same frame/stem.

I suggest you measure your TCR top tube distance (from seat tube to head tube in a straight line) just to affirm the actual ("effective") length, and if it is, as I suspect, closer to 54 than 56, reconsider your stem length.