Why would a heatsink be listed as LGA775/1156 compatable but not 1366?

[modex20]

Specifically http://www.coolermaster.com/product.php?product_id=6602

 

[BoomerD]

Mounting bracket different, processor size different, many reasons.

BUT,why they could make it so that it's not compatible is another question...

 

[Zap]

It is probably because the TX3 only has three heatpipes, which may be insufficient for the higher TDP.