No, it's because our IFX-14's are lapped (or with "evened-out bases" ) . After I lapped mine, I saw a 6-7 degree improvement when running LinX (in exactly same ambient temp). I also increased the backplate mounting pressure, which probably did the 4 degrees of difference.. by the way, the LGA-1366 mounting bracket is pretty good because once installed, one does not have to remove the motherboard to change CPU's.

Some have reported a 3-5 degree improvement after lapping their TRUE's or IFX-14'es.

They are just great heatsinks with rather thin fins (rather dense, but not too dense array). It's manufacturing at its excellence. Yes, Thermalright does make the base a little convex for a reason, too, but it's for smaller cores. It's always better to be slightly convex than slightly concave. Needless to say, a slightly concave base will fail for obvious reasons.

Also, the IFX-14 has four 8mm heatpipes, which are better than six 6mm heatpipes due to greater internal volume for absorbing and transferring heat. Less heatpipes also allow for better airflow, which cools the back of the fins.

The fins on the IFX-14 still look thinner, therefore, each cm^2 of surface area is doing a better job. The NH-D14 is just bigger with more surface area anyways. So, it makes sense to me that the NH-D14 does 2 degrees better than an IFX-14. 120mm to 140mm is still better, but not exponentially better, especially with those longer heatpipes that become less efficient outwards.

Asus Triton 88 is the one that just lost to the NH-D14, after having recently taken the heavyweight belt from the IFX-14.

Yes, I think soo too.

Try Linpack 64-bit

Next time maybe you can post a watchable screenshot. Testing inside a case in not relevant because its not something you can standardize. Also the fans you are using, the ambient temperature are other important factors. Liquid pro is also a thermal compound not very common but a few degrees better than a regular paste. I can guarantee you that the Noctua will be at least 4 degrees better than your IFX with the same fan and thermal compound setup.