Which Laptop CPU would be more powerful?

A 2nd Gen Intel i7-2640M running at 2.8 Ghz or a 5th Gen Intel i3-5010U running at 2.1 Ghz.

Both are dual core processors used in Lenovo Thinkpads.

Technically the i7 would be faster and better but I've researched a lot about Lenovo thinkpads and it's a fact that the i7 core inside a Lenovo ThinkPad gets hot and when it gets hot you lose speed and Power however the duel set of Cores in the slower older machine has been shown to outperform the i7 once the i7 gets hot if you know how to do a little bit of engineering you can compensate for this problem by extending the heatsink

Can conservatives Please stop WORSHIPING David Duke, Charles Manson, and Ted Bundy?
And can they Please stop making OJ Simpson, Charles Manson, and Saddam Hussein look like ANGELS?