AMD Ryzen Threadripper: What you need to know about AMD’s new monster CPU and X399 chipset

Literally the biggest processor we’ve seen this year

AMD’s new Ryzen Threadripper processors are so good that we can almost forgive it its ridiculous name. That puny quad-core CPU you’ve got in your current rig? Threadripper will, well, rip through it like a sledgehammer through a paper wall.

These may quite literally be the biggest processors to debut this year, measuring a gargantuan 72 x 55mm. They’re so big that they positively dwarf Skylake-X, which can hardly be considered small in its own right. AMD even came up with a fancy new mounting mechanism (read the installation instructions beforehand!) for the massive SocketTR4, comprising Torx screws and a mounting bracket for the CPU itself.

Here’s what you need to know about AMD’s new darling. And in case you need it, we’re recapped the specifications and the local prices here:

It’s a Ryzen CPU at heart

The name Ryzen Threadripper gives this away already. Despite its high-end desktop (HEDT) leanings, Threadripper shares the same underlying architecture as the mainstream Ryzen CPUs. This is a neat bit of scalability, where the same architecture serves as the foundation for everything ranging from the entry-level Ryzen 3 chips to the ultra-enthusiast Threadripper.

The basic building block of Ryzen is a 4-core CPU Complex (CCX) that is associated with 8MB of L3 cache. This CCX is in turn linked to another via AMD’s high-speed Infinity Fabric interconnect, comprising an 8-core silicon die that you may have seen referred to as Zeppelin.

The 16-core Threadripper 1950X features two Zeppelin dies located at opposite corners, both of which are also joined by the Infinity Fabric interconnect. The 12-core 1920X uses two 8-core dies as well, but one core on each CCX has been disabled in a 3+3+3+3 arrangement.

This symmetrical disabling of cores in each CCX is what allows AMD to scale core, thread, and cache quantities to target the full spectrum of the client, server, and HPC markets.

Two dual-channel memory controllers sit on each 8-core die, so Threadripper supports quad-channel memory configurations.

In the run-up to Threadripper’s release, pictures began circulating on the interwebs, showing what looked like four Zeppelin dies underneath the heat spreader. This prompted talk that this was actually an EPYC CPU in disguise, where two of the dies were disabled.

That’s not the case, and AMD has said that two of the dies are merely spacers to reinforce the chip’s structural integrity. You know, because the processor is really, really big.

AMD X399 is how every HEDT platform should be done

Intel infamously limits chipset and processor features as you move down the product ladder, and this feature segmentation can leave a sour taste in the mouths of customers.

Does X299 have many new features? Oh, it also supports a US$242 processor in the Core i5-7640X? Well, guess what, you’ll have to pay at least US$999 for the 10-core Core i9-7900X and its 44 PCIe 3.0 lanes to enjoy all the features your motherboard offers.

All this is a big reason why AMD’s Threadripper and its X399 chipset feels like such a warm embrace. The Threadripper 1900X starts at US$549, which goes up to US$799 for the 1920X and US$999 for the 1950X.

However, despite the nearly US$500 difference between the top and bottom-end CPU, all three processors will provide 64 PCIe 3.0 lanes from the CPU and quad-channel DDR4-2667 memory with ECC support.

Four of the PCIe 3.0 lanes go to the X399 chipset, but that still leaves a whopping 60 lanes for graphics and storage devices. This means you can run up to three PCIe NVMe devices and 4-way graphics configurations in x16/x16/x8/x8 mode, which is the stuff of enthusiasts’ dreams.

Threadripper supports up to seven PCIe devices at any one time, of which six can even be GPUs with the right motherboard.

The chipset itself also has native support for two USB 3.1 (Gen 2), 14 USB 3.1 (Gen 1), and six USB 2.0 ports.

Don't forget to check out the AMD X399 chipset motherboard options available.

Creator and Game Modes

On the software front, RyzenMaster got a couple of updates as well. There are now tools to allow users to tweak performance for gaming or productivity applications in the form of separate Creator and Game modes.

The main difference is the memory access mode, and you’ll have a choice between Distributed or Local. Distributed mode is the default setting and the one that Creator mode uses. It places the system in a Uniform Memory Access (UMA) configuration, which prioritizes the even distribution of memory transactions across all available memory channels to maximize memory bandwidth.

Distributed mode actually enforces a mix of local and remote memory access, so there will always be some benefit from remote memory channels. AMD says this helps ensure more consistent memory performance in applications with unknown or unpredictable threading behavior, and it’s also best suited to applications requiring high thread counts.

On the other hand, Local mode puts the system in Non-Uniform Memory Access (NUMA) configuration, which divides the processor into two "nodes" containing one die and two memory channels each. This time, access is prioritized according to the physical distance of the memory DIMM from the CPU core accessing it, so the OS attempts to localize a process and its memory transactions within one node before engaging the other.

The aim is to reduce latency, even at the possible expense of memory throughput, but AMD says modestly threaded applications like games can benefit from this, which is why Gaming mode puts the system in NUMA configuration. 

In fact, the company is claiming a 5 per cent improvement on average, with peaks of up to 10 per cent in certain titles.

Game mode also turns on something called Legacy Compatibility Mode, which turns the 1950X into an 8-core/16-thread part and the 1920X into a 6-core/12-thread chip. Some games, such as DiRT Rally and Far Cry Primal, can’t run with more than 20 logical cores, so this helps ensure compatibility.

Furthermore, AMD claims that some older titles show performance improvements when given less cores to work with, including games like Dota 2, Heroes of the Storm, and Civilization VI.

Read Next: AMD Ryzen Threadripper vs. Intel Core i9-7900X: The fastest chips money can buy

Meanwhile, stay tuned to everything related to AMD's Ryzen Threadripper from the below list.

Our articles may contain affiliate links. If you buy through these links, we may earn a small commission.