AMD Pre-Announces 64-core Threadripper 3990X: Time To Open Your Wallet

Ever since AMD announced its latest enterprise platform, Rome, and the EPYC 7002 series, one question that high-end desktop users have been wondering is when the 64-core hardware will filter down into more mainstream markets. White today AMD is announcing their Threadripper 3000 platform with 24-core and 32-core processors, the other part of AMD’s announcement today is that yes, they will be selling 64-core hardware to the masses, in the form of the Threadripper 3990X.

AMD isn’t giving too many details away just yet. As we predicted, there was room at the top of AMD’s naming strategy to expose more Threadripper hardware: one does not simply stop as the 3970X being the most powerful processor, and the 3990X will certainly take the mantle. AMD is announcing today that the 3990X will have 64 cores, 128 threads, and will have the full 256 MB of L3 cache.

The 3990X will be the high-end desktop equivalent of the EPYC 7742. This means that inside it will have eight chiplets, each with 8 cores enabled. This is compared to the 3960X/3970X being announced today, with 24 and 32 cores respectively, which only have four chiplets. We can tell that the four chiplet designs are that way by the L3 cache: when only four chiplets are active, it has 128 MB of L3 cache, however with all eight chiplets, the 3990X will have 256 MB of L3 cache. That’s a sizeable processor, and seemingly unthinkable for a consumer part. However, as we’ve learned from AMD since introducing Ryzen, they like to go aggressive and offer some level of parity between consumer and enterprise hardware.

One thing that will differentiate the 3990X from the EPYC hardware will be memory and PCIe count. We fully expect (although not confirmed) that the 3990X will have quad channel memory and 64 PCIe 4.0 lanes, compared to EPYC which has eight channel memory and 128 PCIe lanes. AMD has also confirmed that the 3990X will have a TDP above and beyond the EPYC 7742's, with the 3990X coming in at 280W TDP. If this seems familiar, then this is the same TDP as the 24-core and 32-core Threadripper parts. As a result, we do expect the per-core frequency of the 3990X to be higher than the EPYC, but lower than the other Threadrippers.

In our testing of the 3970X 32-core hardware, we saw that in the 280W TDP we had around 75W reserved for non-core activities, and 205W for the cores. Non-core activities in this instance means PCIe, Infinity Fabric, and memory channels. Moving up to the 3990X means double the IF connections, but the others stay the same. So even if that means we reserve 100W for non-core activities, that leaves 180 W for 64 cores, or around 3 W each per core when at full load. Based on what we know about Zen 2 frequency scaling with power, around 6 W per core gives 4.0 GHz, so 3 W per core should offer low-to-mid 3.0 GHz all-core frequencies.

This prediction actually fits well: AMD’s 240 W EPYC 7742 is a 2.35 GHz base, 3.2 GHz turbo, so we should expect frequencies north of that. There’s also the EPYC 7H12, a new part recently announced to cater for the high frequency market. Like the 3990X, it also has a 280W TDP, but a 2.6 GHz base frequency, and a 3.3 GHz turbo. There is no official pricing on the 7H12 as yet.

AMD is set to launch the Threadripper 3990X in 2020. Unfortunately we don’t get any more info than that at this time, but if we consider the 24-core 3960X at $1399, the 32-core 3970X at $1999, I can easily see this processor being at least $3999, if not more. The EPYC 7742 has an MSRP of $6950, and the 7H12 is higher than that, so the 3990X is going to cost a pretty penny by comparison.

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