Intel sent the Alder Lake chips in a special package that includes a cardboard insert with a printout of the Alder Lake microarchitecture, but we're most interested in the Core i9-12900K and Core i5-12600K that we'll put through their paces in our upcoming review.
Here we can see the top of the 12900K and the bottom of the 12600K next to the previous-gen 11900K and 10900K processors. The much larger array of contact pads on the rectangular Alder chips stands out — Alder Lake-S drops into the LGA1700 socket with 1700 pins, while the Rocket and Comet Lake chips drop into the LGA1200 socket with 1200 pins.
The Rocket and Comet Lake chips measure 37 x 37mm, but the larger rectangular Alder Lake chips measure 45 x 35mm. While this is a big increase in the physical size of the chip, it still pales in comparison to the 45 x 45mm Core I9-10980XE, not to mention the massive 56 x 71mm Xeon Gold 6154 or the 70 x 59mm Threadripper 3960X we used for comparison. (We also threw in the OG Intel 8086 from ~1976, which measures 13 x 51mm.)
We measured the thickness of both Alder and Rocket's PCBs, and they're both around the same ~1mm, though Alder Lake's PCB is slightly thinner.
Rocket Lake's total Z-Height (thickness) from the top of the integrated heat spreader (IHS) to the bottom of the PCB measured 5mm compared to the Alder's ~4.5mm, meaning that Alder Lake isn't quite as tall as its predecessor. This aligns with reports that the LGA1700 socket is 'shorter' than LGA12XX and 115X, with a total 8.91mm Z-height compared to 9.29mm.
Intel shared this image of the progression of its chip packages over the last few generations, with the company gradually thinning the die to improve thermal dissipation. That also helps improve overclockability by adding additional thermal headroom.
This time around, Intel reduced the PCB thickness by an additional 35% and thinned the STIM (Solder Thermal Interface Material) by 15%. Intel also used a larger, thicker copper IHS that serves as a thermal slug to absorb heat. You'll notice that Intel's image shows all four generations of chips with the same overall height, yet we've measured a ~.5mm Z-Height reduction for Alder Lake. We're following up with Intel to learn more.
You'll need a cooler conversion kit if you want to use existing LGA 115X coolers with the Alder Lake chips, and there are reports that some kits don't maintain an even pressure due to the difference in Z-Heights. We'll update you as we learn more, but be sure to do due diligence when you select your cooler.
You'll also notice that Rocket Lake's IHS now has a faint silkscreened triangular logo on the bottom left, which coincides with the typical yellow triangle printed on the PCB that you use to align the processor in the socket. Additionally, Alder Lake has a unique notch arrangement to help prevent installing the processor into the socket incorrectly, with two notches at both the top and bottom, as opposed to LGA 12XX and 115X that came with two notches (one on either side).