Low power Alder Lake explained

"Starting with the low power processor at 9 W, Intel classifies this as a U-series processor featuring two performance cores, eight efficiency cores, and 96 execution units of graphics in the silicon. As with the ultra low power Tiger Lake processors, this uses an Intel design known as ‘BGA Type4’, or ‘UP4’, that combines both the CPU and the chipset on the same package. and is the smallest such processor package that they offer."

"At 15 W, we’re in the more traditional U-series that we are familiar with. The package size increases to what Intel calls BGA Type3, or UP3, but you’ll notice that the CPU layout looks identical to the 9 W version. That’s because it is the same – up to two performance cores and eight efficiency cores, then 96 execution units on graphics. This is going to be important: for a market readily served today by the Core i9-1195G7 – an 11th Gen 15 W processor with four large cores – Intel is pivoting to fewer performance cores and more efficiency cores for their 12th Gen chips. It’s also worth noting that the chipset is also on die, but offers more functionality than the 9 W chips."

Source: AnandTech