These pads are just efficient as ordinary thermal grease or even better
Thermal pads are dreaded by overclockers as they provide very low heat transfer between the heat source and the heat spreader.
On the other hand, thermal pads have some real advantages over normal thermal grease as these do not solidify like old, ordinary thermal grease does and they are also not pushed out when the heat spreader is tightly pressed on the chip.
In addition, thermal pads are easier to install by the user and are more efficiently used as, ideally, there is almost no waste.
Sony Chemical & Information Device Corp exhibited a prototype that they’ve called a “thermal sheet” and the demonstration showed that the pad had relatively the same cooling performance as an unnamed thermal grease.
The name of the new product reportedly is "EX20000C" and SONY touts that the sheet is just 0.3-2.0mm thick while its thermal resistance is just 0.4-0.2K cm2/W using a compressive load of about 1-3 KG force per square cm.
All in all, this is about five times the performance of Sony’s current thermal pad, the "EX50000.”
The demonstration showed two identical processors and cooling systems that were using an unnamed thermal grease and SONY’s new "EX20000C" thermal sheet.
The processor using Sony’s new "EX20000C" thermal sheet was able to stay about 3 degrees cooler than the setup using thermal grease.