Review: AMD Ryzen Threadripper 1950X and 1920X

Introduction

Is Threadripper one of the best CPU names of all time? AMD certainly thinks so, and the company is in high spirits, having introduced competitive Ryzen 3, 5 and 7 processors and following-up with Threadripper CPUs that tear apart the nearest Intel equivalent in multi-threaded workloads.

Ryzen 9 would have been the more obvious branding choice, but Threadripper is testament to AMD's renewed confidence. The firm freely ridiculed Intel's alternatives at a recent press event, claiming that Core i9-7900X's $999 price tag is a sign of AMD Threadripper bringing value to the market prior to release.

Should a company who has failed to live up to consumer expectations in recent generations be quite so cocky? That's up for debate, but this is the first time in a long while that AMD has been competitive, and with Threadripper we reckon it has done enough to sit back, put its feet up, and enjoy seeing Intel beaten into second place... for the time being.

AMD Ryzen: The Complete Stack

Slotting in at the head of AMD's desktop CPU portfolio, Threadripper is a High-end Desktop (HEDT) solution designed to compete with Intel's recently announced Core X Series. At launch, a trio of many-core Threadripper CPUs is to be made available; the eight-core, 16-thread 1900X; the 12-core, 24-thread 1920X; and the range-topping 1950X touting a whopping 16 cores and 32 threads.

It's worth taking a moment to absorb the information presented above. Six months ago, AMD barely had a CPU worth buying for the performance junkie, and certainly didn't have anything that could command a $999 price tag. Fast forward to today and the manufacturer has a dozen processors that are each competitive at their respective price points.

The entire stack is based on the same Zen architecture, but what sort of wizardry is AMD using to get 16 cores into a single chip? It's obvious, isn't it, take two Ryzen 7 processors and tie them together into a single giant package known as TR4. Doing so results in two die, each carrying a pair of CPU Complexes (CCXs) that in turn provide four simultaneous multi-threading (SMT) cores. Infinity Fabric connects the dots at the expense of a little latency, and though it's hardly the most elegant design - Intel famously referred to it as 'glued together' - the end result is up to 32 threads from a single 180W chip.

Do note that while Ryzen Threadripper has been pictured with what appears to be four die beneath the lid, only two, positioned diagonally from one another, are actual die - the other two are merely placeholders positioned to stablise the cover in preparation of cooler mounting. This isn't a 32-core Epyc chip in disguise.

Putting The Squeeze On Pricing

Appreciating that the Zen architecture isn't a match for Intel Kaby Lake when it comes to instructions per clock (IPC), AMD Threadripper continues the Ryzen strategy of offering more cores or features for less than the Intel equivalent.

Comparing the AMD Ryzen Threadripper 1950X with the Intel Core i9-7900X reveals a couple of obvious truths. Intel's Core i9, at up to 4.5GHz, and with greater IPC to boot, is going to remain comfortably ahead in a single-core race. Hoping to close the gap, AMD is using the best five per cent of dies to create Threadripper CPUs, and has been able to ship with a maximum eXtended Frequency Range (XFR) of 4.2GHz. Ryzen 7 was able to apply this peak speed on two cores when a suitable cooler was installed, but Threadripper, with two die, is able to run at 4.2GHz across four cores.

That won't be enough to keep pace with Core processors in single-threaded workloads, but Ryzen has historically worked best when all threads are to put to task, and the same is true of Threadripper. With 32 available threads, compared to 20 from Intel at the same price point, the 1950X should stand alone in more demanding scenarios that are familiar to content creators, multi-tasking gamers and software developers.

AMD's willingness to offer more cores at no extra cost is a key attraction, and the company extends its assault on Intel's HEDT line-up by ensuring all Threadripper chips retain a full set of features. Whereas Intel is known to disable certain capabilities on anything but the range-topping part, all three launch-day Threadripper CPUs offer the full complement of 64 PCIe lanes, XFR scaling and support for quad-channel memory.