Threadripper in the flesh
Any discussion of Threadripper cannot overlook the fact that these are enormous chips, quite unlike anything that's graced a desktop system in recent memory. Each Threadripper CPU ships in a plastic protective shell that's part of an elaborate and (in theory) durable box.
While my business-major instincts are hitting on words like "economies of scale with Epyc" when thinking about the sheer size of the Threadripper multi-chip module itself, it's also ingenious marketing. Most people have an inescapable lizard-brain instinct that bigger things are better, and even compared to Intel's LGA 2066 CPUs, the massive Threadripper chips evoke an undeniable reptilian satisfaction when you handle them.
Perhaps because of the risks of dropping a ZIF chip this large onto a socket the wrong way, Threadripper CPUs rest in a semi-permanent plastic mounting frame. The assembly pops, locks, and drops into an enormous new socket called TR4. Unlike the pin grid array of Socket AM4, TR4 is a 4094-pin land grid array that's like a much larger version of Intel's modern sockets. TR4 is outwardly similar (if not identical to) AMD's Socket SP3, which plays host to Epyc server chips. Despite that similarity, the two chip families can't be switched between sockets. You'll still see artifacts of this shared lineage in the "SP3 SAM" stamp on the TR4 retention bracket and pin protector, though.
Installing a CPU in Socket TR4 will be a new experience for anybody not accustomed to data-center hardware. AMD includes a torque wrench (that's also a Torx driver) in its Threadripper packaging. Use of this wrench should be considered mandatory for installing and uninstalling Threadripper CPUs. Should you lose yours, the torque spec is 1.5 newton-meters.
The first step is to loosen each Torx screw using the order printed on the retention bracket itself (3-2-1 to loosen, 1-2-3 to tighten). Once the bracket is open, it reveals a spring-loaded receiver frame that can be released by pulling gently on the two blue tabs toward the top of the socket.
Once the frame is vertical, builders will need to gently slide out a clear plastic external cap before sliding the Threadripper assembly into the guide rails on the frame. The carrier will slide into the receiver until it gently clicks into place at the bottom of its travel.
Once you feel the click, make sure to take the gray plastic pin protector off the socket before swinging the receiver frame and CPU down onto the socket. The receiver frame will also click once it's locked back into place. Finally, lower the retainer bracket back onto the CPU and work around the three Torx screws with the torque wrench. I found that doing a half-turn on each screw in sequence was the best approach. The torque wrench will click once you've tightened each screw adequately.
Overall, this sequence sounds more intimidating than it is. Just watch an instructional video a couple of times before proceeding, and whatever you do, don't plop the CPU directly onto the pins or remove it from the plastic carrier frame. I'd also keep the external cap and pin protectors stored away in your motherboard box, since you won't ever want to leave a socket this large exposed for any length of time. Repositioning bent pins on this baby will likely not be possible without damaging others in the socket.
Applying thermal paste to a heat spreader this large also requires more planning than the usual "grain-of-rice-and-squash-it" method. The fine folks at GamersNexus have detailed several different methods of paste application and their effects on performance. The short version is that AMD recommends applying five dots of compound on the heat spreader , but I found it easiest to apply a generous blob of compound (about three times as much as one might normally apply for LGA 115x CPUs) smack in the middle of the "Z" of the Ryzen logo on the heat spreader. Regardless of the method you use, you will need much more thermal compound than with smaller CPUs to achieve full pasting of your liquid cooler's cold plate.
Once the CPU is installed and pasted, the next step is getting the right cooler on top. Although air coolers for Threadripper are in the pipe, we imagine most will want to use liquid coolers for the most socket clearance and best performance. AMD includes a Socket TR4 mounting bracket in the box for Asetek-based liquid coolers from a wide range of manufacturers, including Corsair, NZXT, Thermaltake, and Arctic Cooling. This bracket installs easily on unadorned Asetek coolers like the Thermaltake Water 3.0 Ultimate AMD sent us for testing. Other, fancier coolers, like the Corsair H115i that I often use in testing, have preinstalled brackets that will pop off the pump head with a firm counterclockwise twist.
The Threadripper cooler bracket has asymmetric lugs that are narrower at the top of the socket, so builders will want to make sure the top of the pump head and the top of the bracket are in agreement. Once you have the bracket on your liquid cooler of choice, follow the tightening order near each screw on the bracket until they're all snug, and you're set.