AMD’s Threadripper platform gave a hefty boost to the high-end desktop (HEDT) market: 16 cores and 32 threads using AMD’s Zen architecture. Today, AMD announced the second generation of Threadripper: it’s twice as big again, with up to 32 cores and 64 threads, and it uses the revised Zen+ core of the second-generation Ryzen chips.
The basic building blocks of Threadripper 2 are the same as the first-generation parts. Threadripper processors are multi-chip modules (MCMs) containing multiple dies and Infinity Fabric interconnects. AMD calls the basic building block of each chip a Core Complex (CCX), which has four cores, eight threads, and 8MB of level 3 cache. Each chip contains two CCXes. The first round of Threadrippers had four chips, with two of them active and two inactive, for a total of 16 cores and 32 threads. The new second-generation parts announced today make all four chips active, bringing the counts up to 32 cores and 64 threads.
This is the same basic layout as the company’s Epyc server processors, but there are some differences. Each chip has two memory controllers. In Epyc, all four pairs of memory controllers are enabled, for a total of eight memory channels. In Threadripper 2, only two of the chips have their controllers enabled, for four memory channels total.
The pair of chips without active memory controllers will have to route all of its memory requests through the pair of chips with memory controllers, meaning that it will experience slightly higher memory latency. The newly active chips also aren’t contributing any additional PCIe lanes, either; Threadripper 2 will have 64 PCIe lanes like Threadripper did, and not the 128 of Epyc.
Zen+ uses a 12nm manufacturing process, generally reducing power consumption compared to the 14nm Zen, but doubling the number of chips has substantial impact. The thermal design power of the new processors is 250W, up from 180W for first-generation Threadrippers. This means that some first-generation X399 motherboards may not be able to deliver enough power for the new processors, and we’re likely to see a refreshed range of motherboards to accommodate the greater demands.
Final specifications aren’t decided yet, but AMD has two samples. One is a 32-core/64-thread part; the other is a 24-core/48-thread part. Both have a base frequency of 3GHz and a turbo of 3.4GHz. This turbo frequency is subject to change as the products near their release. The chips are due to ship in the third quarter of this year.