AMD no longer ships its Ryzen Threadripper CPUs for high-end desktops and positions its Ryzen Threadripper Pro for workstations. But now that single-socket motherboards for AMD's 4th Generation EPYC 'Genoa' processors are available, you may no longer want to settle with 64-core Threadripper Pro but opt for a monstrous system with 96 cores and up to 12 channels of DDR5 memory.
Recently ASRock Rack introduced several single-socket SP5 motherboards (opens in new tab) for AMD's EPYC 9004-series processors (via HardwareLuxx.de (opens in new tab)), including the Deep Micro-ATX GenoaD8UD-2T/X550 and GenoaD24QM3-2L2T/BCM motherboards that are formally aimed at servers, but which can be used to build an ultimate battle station with a 96-core CPU and loads of memory assuming that you can afford the CPU and find an appropriate chassis.
Since the ASRock GenoaD8UD-2T/X550 (opens in new tab) and the GenoaD24QM3-2L2T/BCM (opens in new tab) are indeed server motherboards, they support everything one comes to expect from a server, including eight or 24 slots for DDR5 memory modules, four PCIe 5.0 x16 slots with CXL 1.1 on top, two M.2-2280 slots for SSDs with a PCIe 4.0 x4 interface, multiple MCIO connectors supporting PCIe 5.0 or SATA connectivity, two or four 10GbE ports (controlled by the Intel X550 or the Broadcom BCM57416 chip), one GbE connector for management, and the Aspeed AST2600 BMC.
Meanwhile, the motherboards do not have common desktops and workstation features, including high-speed USB4 or Thunderbolt 3/4 ports, audio connectors (and appropriate controllers), and conventional SATA connectors on the motherboard.
Building a workstation featuring the GenoaD8UD-2T/X550 will be pretty tricky as a performance-demanding enthusiast will need to procure an M.2-to-PCIe x16 adapter card to take advantage of the latest SSDs featuring a PCIe 5.0 interface, a proper cooling system for AMD's EPYC processor in LGA 6096 packaging, and so forth. Also, remember that EPYCs do not overclock (96-core monsters also do not feature high clocks), and they are supposed to work with DDR5-4800 memory, which may not be a massive problem as the platforms have eight or 12 memory channels that provide plenty of bandwidth.
Building a powerful workstation based on AMD's 96-core EPYC is expensive and peculiar. However, the reward is, of course, loads of cores and memory, and if you need to run workloads that can scale to 96 cores, it might be worth the money and trouble.
My dreams for the next HEDT platform would be similar, but right now, I care more about frequency than core count. I game, run the full Adobe suite, do heavy encoding, run a few Hyper-V VMs and an NVR, all on one system. Since I game a lot, frequency is important, and all other applications can benefit from that. I don't need 64 or 96 slower cores if applications aren't going to use those cores.
Having 16-24 cores that can run 5.2+GHz stable all-core (none of those efficiency cores), non-stop, would be awesome. With the 5 NVMe drives I run (don't forget at least 4 SATA ports for HDD storage), dual 3090 GPUs, USB and audio expansion boards, capture card, I need more PCI-e lanes than Intel's puny 20 lanes. What a joke - 16+4 lanes. I know PCI-e v5 has double the bandwidth of v4 and running a GPU at x8 on v5 is totally fine, but I run my systems for 6-7 years before upgrading, and that doesn't leave much room for future upgrades or other expansion cards. I'm also not in a rush to move to 128GB RAM yet, 64GB of higher-bandwidth memory is fine for now.
Bring back enthusiast HEDT! Give us those lanes and memory bandwidth! Give us high-frequency CPU options as well as high core-count options! The way Intel has been failing, I'm likely to move to AMD, even though they aren't king in gaming, and I personally don't find AMD as stable as Intel.
One rig to rule them all, and in the darkness, bind them.
This is the inherent problem with the extra bandwidth in newer pcie revisions. Your addin cards have to support it and/or your board has to properly support bifurcation or your benefit is zero.