OCC has published a review on the Thermalright Ultra 120 eXtreme Rev.C

The temperatures delivered by the TRUE Revision C as delivered, gave results that matched the original TRUE I have been using in my testing when overclocked. Even with the reduced surface area caused by opening up the fin array, the results are similar. The differential of 1=B0C in the stock testing when comparing the two shows that they are pretty much spot on performance wise. What was kind of surprising was that the TRUE copper gave a slightly better idle temperature when overclocked and the same load temperatures as the Revision C. That makes the TRUE Revision C still one of the top performing heat sinks I have tested, yet the Copper version was a slight let down with temperatures that were almost identical to the Copper/Aluminum models.

Thermalright Ultra 120 eXtreme Rev.C Review