AMD THREAD RIPPER 2
So fast it’s frightening
Last year, AMD’s Threadripper shook the high-end desktop computer world. Originated as a skunkworks project by a bunch of AMD architects and enthusiasts, the new chips knocked Intel off its perch for the first time in a generation.
The blue team responded with the mighty Core i9-7980XE, but we always knew Threadripper had more to offer – not least because there were two inactive dies sitting under its massive heatspreader. With this second generation, AMD takes on Intel on two fronts. The first salvo is the Threadripper 2950X, an out-and-out enthusiast’s chip. The second is the 2990WX ( see p58), designed for ultra-high-end workstations such as Scan’s 3XS WA6000 Viz ( see p59).
Something shared
The new Threadripper CPUs sport the same upgrades that their mainstream Ryzen siblings introduced this year. Highlights include XFR 2, Precision Boost 2, and Precision Boost Overdrive, which together push performance higher in both lightly threaded and multithreaded tasks.
XFR 2 allows the CPU to raise speeds beyond their normal range where temperatures allow: AMD claims that with liquid cooling this can provide an additional 16% performance boost, compared to an average air cooler. Precision Boost Overdrive applies a small blanket overclock, while leaving the automatic boosting algorithms active. As a result, 2nd Generation Threadripper CPUs should be measurably faster than the original generation at almost every task.
Something different
Architecturally, the two processors are all but identical. Each one comprises four dies, with two core complexes per die, each of which in turn contains four cores for a total of eight cores per die.
The key difference is that, on the 2990WX, all of this silicon is available for processing duties – a whopping 32 cores servicing 64 threads – while on the 2950X two dies are disabled, leaving you with 16 functional cores. The 2990WX has 64MB L3 cache to the 32MB of the 2950X, in addition to each core’s onboard 512KB L2 cache.
There’s a catch, though, because not all of these cores are wired up in the same way. The first two dies – the ones that are active in both chips – have a direct connection to the rest of the system, such as the PCI-E bus and memory, and can communicate with one another using AMD’s Infinity Fabric. The extra cores in the 2990WX effectively sit on an island; to access system resources they must communicate through the other two dies, which adds a lot of latency, especially in memoryintensive programs.
Clock speeds are different too. Where the 2950X can boost from 3.5GHz to a maximum frequency of 4.4GHz, the weightier 2990WX comes with a lower base clock of 3GHz, and a maximum boost of 4.2GHz. As the graphs opposite and on p58 show, this erodes the 2990WX’s advantage, and is part of the reason it can can actually be slower at some tasks.
Compatibility
In October, these two chips will be joined by the 2970WX – a 24-core version of the 2990WX. At some point, the 12-core 2920X will replace the current 1920X. All four Threadripper CPUs will be compatible with the current TR4 socket and X399 motherboards, although you’ll likely need to apply a BIOS update.
Clearly these new processors add up to a formidable lineup. For all-round speed, Intel’s Core i97980XE is still top dog, but at £1,800 it’s more expensive than any AMD CPU, and in highly multithreaded tests (such as Cinebench R15) it simply can’t keep up with a high-end Threadripper chip. The second round of the CPU showdown is underway, and once again AMD has come out swinging.
“The second round of the high-end CPU showdown is now underway, and once again AMD has come out swinging”