The term "comparable" is used to state either all of the pros and cons of two factors, or a specific area's pro and cons, and state the differences between them, using a certain system, take scoring as an example.
Regarding CPUs, in order to compare between two processors in regards to efficiency, you only have four ways to compare between them:
1- Power consumption ratio (Watts).
2- Price tags ($$$).
3- Average heat under load.
4- Bottle necking other parts of the system.
Now, since we eliminated the price tags element, we can decide to choose to compare between any two given processors, since we are comparing based on brand, using all pros and cons as deciding factors.
AMD FX 8350 Vishera Octa-Core Vs. Intel i7 3930k Hexa-Core.
1- Winner? Intel i7 3930k. (Although Intel's i7 3930k has a higher TDP, many reviewers have proven via testing methods that Intel's processor performs better than AMD's processor, both on Idle mode and when it's handling high load.)
2- Eliminated.
3- Winner? Intel i7 3930k. (Using retail coolers.)
4- Winner? None. (Considering both do not bottle neck any modern gpu.)
(Based on this review:
Intel i7-3930K vs AMD FX-8350 in Processors (CPUs).)
Overall winner: Intel 3930k.
So, no biased fan-boy based opinions, Intel > AMD in processors if we disregard the cash value. Even if you don't like how that sounds. I did not intend to sound aggressive, in case I did, I apologize.