In many cases, it may not make a lot of sense to purchase the 35W Intel Sandy Bridge T-variant parts because they are typically more expensive than the slight power savings and heat differences can justify in real-world usage. One aspect where the parts shine though is in small form factor (SFF) installations. When it comes to SFF, the height of the heat sink-fan (HSF) is often a concern and an aftermarket solution is typically sought.
I recently put together a system with an i3-2100T and was pleasantly surprised by just how slim the HSF is. Unfortunately, back when Andrew reviewed the i3-2100T, he did not have access to the retail HSF so you can see it in all of it's glory here. Note that this is not the HSF Intel is working on for SFF installs that we learned about from the DH61AG board review.
The measured height from the top of the board to the top of the HSF is 1-7/16" for the i3-2100T whereas the i3-2100 is 2-1/8". The AA cell pictured is 2" in height. You'll also notice the fan design is different with the i3-2100T fan being slimmer with 11 blades compared to the i3-2100 fan with 7 blades.
Hopefully, you'll find this information useful if you're planning out an installation in a tight space. Photos after the break.