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AMD's Ryzen Threadripper 2950X CPU reviewed


Threadripper, refined

AMD's Ryzen Threadripper 2990WX may have a legitimate claim to being the world's fastest desktop CPU, but it's also $1800. Even for a high-end desktop part, that's rather pricey for anybody who's not making money with those CPU cycles, and those 32 cores and 64 threads don't benefit every application. The 2990WX is outstanding when a program can yoke every one of its cores and threads, but our tests suggest most apps on the desktop hit the diminishing-returns point in the scaling curve around 16 cores and 32 threads.

Enter the Ryzen Threadripper 2950X. Compared to the Threadripper 2990WX's wild core count and rather unusual NUMA arrangement, the 2950X is downright simple. It uses the same two-die multi-chip-module configuration that the Threadripper 1950X and Threadripper 1920X introduced a little over a year ago. It keeps the 1950X's 16-core, 32-thread configuration, too.

Those two dies are joined using a pair of unidirectional Infinity Fabric links capable of 51.2 GB/s of unidirectional bandwidth for an aggregate of 102.4 GB/s bi-directional throughput, at least assuming they're talking to DDR4-3200 RAM. As a consequence of the move to Zen+ Zeppelins underneath its heat spreader, the 2950X gains support for DDR4-2933 RAM out of the box.

As a beneficiary of the Zen+ microarchitectural improvements that first appeared on second-generation Ryzen chips in Socket AM4, the 2950X implements three improvements over first-generation Threadrippers. Precision Boost 2 lets the chip gracefully adjust its clock speeds as the number of loaded cores and threads climbs. The Threadripper 1950X, in contrast, maintained a concept of a four-loaded-core boost clock and an all-core boost clock, meaning applications that ended up somewhere in between weren't necessarily taking full advantage of the chip's power and thermal headroom. Precision Boost 2 might increase the 2950X's performance in some workloads as a result. AMD corporate fellow Joe Macri described one of the company's goals for second-generation Threadrippers as "eliminating performance cliffs," and Precision Boost 2 does just that.

Second, Extended Frequency Range 2 (XFR 2) allows the 2950X to take advantage of ambient conditions and beefy cooling hardware to deliver better sustained performance under multi-threaded workloads. Unlike the first generation of XFR, which applied a fixed offset to both single-core and all-core clock speeds when conditions allowed, XFR 2 only affects multithreaded speeds.

Finally, the Threadripper 2950X is built on GlobalFoundries' 12LP process. 12LP allowed AMD to use better-performing transistors in critical parts of the Ryzen die, resulting in better cache and memory latencies.

AMD bins the top 5% of Ryzen dies for use in Threadrippers, and the 2950X puts those select slices of silicon to use by posting a 4.4-GHz single-core peak clock speed, the highest of any Ryzen CPU so far by a nose. Bit by bit, Ryzen chips are eliminating the peak clock speed deficits that have been part of the reason Intel CPUs remain superior for desktop responsiveness and lightly-threaded performance. The 2950X isn't going to boost to the same peaks as a Coffee Lake Core i7-8700K, to be certain, but 4.4 GHz is not far off the Turbo Boost Max 3.0 speed of 4.5 GHz that the similarly-priced Core i9-7900X puts up.

  Cores/
threads
Base
clock (GHz)
Peak boost
clock (GHz)
L2
cache (MB)
L3
cache (MB)
TDP Suggested
price
Threadripper 2990WX 32/64 3.0 4.2 16 64 250 W $1799
Threadripper 2970WX 24/48 12 64 $1299
Threadripper 2950X 16/32 3.5 4.4 8 32 180 W $899
Threadripper 1950X 16/32 3.4 4.2 8 32 $999
Threadripper 2920X 12/24 3.5 4.3 6 32 $649
Threadripper 1920X 12/24 3.5 4.2 6 32 $799
Threadripper 1900X 8/16 3.8 4.2 4 16 $549

Perhaps most importantly, those benefits don't make for a more expensive chip. The Threadripper 1950X already made waves in the high-end desktop market by bringing its particular complement of cores and threads to a lower price point than ever before, and the Threadripper 2950X lops another $100 off that chip's $999 suggested price. Threadripper 1950X prices have fallen far below that initial $999, to be sure, but once old stock of those parts filters out of retailer warehouses, the 2950X will be in a good position to compete against the Core i9-7900X. The 2950X isn't for sale yet, but it'll hit retailers August 31.