Review: AMD Ryzen Threadripper

Review: AMD Ryzen Threadripper

AMD rips Intel a new one at the high end of the CPU world

16 cores. 32 threads thanks to SMT (Simultaneous Multithreading). Threadripper is indeed a behemoth. It’s no wonder that the chip measures 73mm by 56mm, around twice the size of the CPUs we’re used to on the desktop. We weren’t expecting samples to arrive for another few months, but AMD gave us a nice little surprise with the retail release in August. We were given the top of the line 1950X (AU RRP $1,440, NZ RRP $1,600) and its slightly smaller brother the 1920X (AU RRP $1,150, NZ RRP $1,280) for testing, and boy did we test the heck out of these chips. There is also the 8 core/16 thread 1900 (AU RRP $549, NZ RRP TBA), which is not tested here.

Unlike other new tech launches, it went off without a hitch – once we’d made a BIOS update to the Asus Zenith Extreme motherboard supplied with it, everything worked perfectly. This a rather different scenario to the Ryzen launch, especially regarding memory support, so we must applaud AMD for getting Threadripper off the ground without any technical issues. Even more impressive though is the bang-for-buck these chips deliver. But enough about that, let’s dig into the details about this new mega-chip. 


First things first. AMD has moved away from mounting the pins on the CPU known as a PGA design (pin grid array) to the same LGA (land grid array) that Intel uses. In other words, the CPU pins are on the motherboard socket, not the chip, and there are 4094 pins in total. Speaking of the socket, Threadripper brings a new socket to the table, known as the TR4. It’s a rather strange design, with the CPU slotting into a plastic holder, which then slides into the swinging socket cover of the TR4. It’s a little inelegant – we managed to snap one of these plastic holders when taking the CPU out. It also means that you’ll need a new X399-chipset based motherboard, and one of the major benefits of this new chipset is a huge boost in the number of PCIe lanes. The 1950X offers a huge 64 PCIe 3.0 lanes, which means there’s an abundance of lanes for your devices. This is exactly what the market these chips are aimed at need, as they’ll likely be running multiple GPUs, SSDs and other devices. One thing you should know about these boards is that they use twin 8-pin power inputs, so it wouldn’t work with our existing testbench PSU which only had one 4-pin CPU/mobo connector; instead we used the Thermaltake iRGB Plus 1250W PSU provided by AMD, and even then we used every single connection included on the PSU thanks to our three SSDs, two for the GPU, and three for the motherboard. 


There’s no cooler included with these chips, and you’re going to need a brute to cool this slab of silicon. Thankfully AMD has also included a special adaptor for existing heatsinks in the packaging, which is compatible with most AIOs. AMD supplied us with the Thermaltake Floe Riing 360 TT Premium Edition, an All-in-one cooler with a 360mm radiator. Despite the water block barely covering half of the CPU, we measured a maximum temperature of just 58C during our Prime 95 stress test on the 1950X. This is because Threadripper is based on the same Zen architecture of the Ryzen series, which uses what AMD calls ‘AMD Sense SMI technology’, which includes aggressive power efficiency technologies, such as monitoring which part of the CPU needs power, and which doesn’t, as well as adjusting core frequencies. Threadripper is also built on a 14nm FinFET manufacturing process to help keep energy needs low. 


Inside the chip are four silicon dies, but only two of these are actually active – the other two don’t contain any working transistors. AMD claims that this is not because the other two are duds, but that they help balance out the design of the CPU for cooling reasons and heatsink mounting. The other two dies actually do work, and they’re known as Core Complexes (CCX), with the 1950X having eight cores, and six on the 1920X. This means the 1950X has a total of 16 CPU dies, while the 1920X has twelve. On both CPUs, each core has a 512K L2 cache per core, and another 16MB of L3 cache per die. That’s a total of 40MB of cache on the 1950X, and 38MB on the 1920X. The two CCX units are connected via Infinity fabric, which AMD says delivers 102GB/s between each CPU die. 


Quad channel memory is supported, with an official top speed of 2667MHz. Unlike Intel, Threadripper supports ECC memory, which is important for valuable data. AMD also includes XMP technology to boost the memory speed even further, but we tested with this disabled, as we have all other recent CPU reviews. AMD supplied us with four 8GB G.Skill Trident Z sticks, but to maintain parity with prior testing, we used two 8GB Ballistix sticks. Unfortunately this led to an issue with our 7-zip benchmark; there simply wasn’t enough memory to feed all of those threads when using the 192MB dictionary size, so we had to use the full 32GB of Geil memory for this test. As a result, we’d suggest taking our 7-Zip results on the 1950X with a pinch of salt, and going for a minimum of 32GB of memory if you do buy one of these chips. All of those cores need plenty of memory to feed.

AMD offers two different memory access modes. For productivity applications, the Distributed mode is recommended, as it prioritises even distribution of memory across all memory channels, and is best for software that has unpredictable threading behaviour. If you’re going to game though, AMD recommends switching to Local mode, which switches the system into NUMA (Non-Uniform Memory Access) mode, which divides the processor into two nodes, each containing a die and twin memory channels. Yet we found switching between these modes made very little difference, apart from a 2% performance drop in 3DMark Cloud Gate. 

This setting can be accessed via the Ryzen Master software, which also includes overclocking features. Threadripper is fully multiplier unlocked, and this software also opens up memory overclocking and voltage adjustment. It’s a very clean UI, though changing some settings does require the user to reboot the PC. 


Like the Ryzen chips we reviewed a few months earlier, the Threadripper CPUs also include XFR, which is similar to Intel’s Turbo Boost Max 3 feature. However, this is dependent upon the thermal conditions that the CPU is undergoing; in our Prime95 test, the frequency was locked at 3.45GHz. Speaking of frequencies, the 1950X has a base speed of 3.4GHz, which can boost all cores to 3.7GHz under load. However, it can hit 4GHz when just four cores are active, or four cores at 4.2GHz when XFR kicks in. On the other hand, the 1920X has a base frequency of 3.5GHz, which can boost all cores up to 3.7GHz. If just four cores are active, it can hit a speed of 4GHz, and with XFR will top out at 4.2GHz.


So basically what we have here is the Ryzen 7 beefed up with more cores and a new socket design. Other than that, it’s still based on the Zen architecture of Ryzen. It’s not quite as affordable as we’d like, with the 1950X priced basically the same as Intel’s i9-7900X, at $1450. But as you’ll see, the Threadripper 1950X runs rings around the i9-7900X when it comes to heavily multithreaded applications.


Intel has been spurred into action with the release of Ryzen, and the Ryzen Threadripper is even more of a threat. When it comes to productivity, Threadripper is now the leading chip compared to the latest Core-X, in the form of the i9-7900X. Intel has a few more CPUs up its sleeve, as does AMD, so it doesn’t look like the CPU wars are going to end anytime soon.

If you’re a high-end creator who relies upon multi-threaded software, Threadripper is definitely for you. Gamers won’t be quite as happy though, unless they really need to run streaming software or other software in the background. We have to hand it to AMD for catching up so quickly, which has seen Intel basically halve the price of its ten-cored CPUs. Now we just need AMD to catch up on the gaming front, which relies as much upon the game developers learning how to use all those cores, as it does AMD educating them.

 - Let’s do this 

To ensure our test results were as close as possible to the recent Core-X testing, we made sure to use the same gear, despite what AMD supplied. They had supplied the board with an M.2 drive, 32GB of memory, a new PSU and cooler. We took out the M.2 drive and used our standard Sandisk SSD, along with 16GB of Ballistix memory. Unfortunately we had to use their cooler and PSU, but in all other regards the systems were identical. 

As you can see from the productivity benchmarks, the Ryzen Threadripper still has the weaker single-core IPC than Intel’s design. However, load up all those cores and it’s a different story. The 1950X took out six of our ten benchmarks. One surprising result was the Handbrake video encode. In the marketing material AMD gave us, it showed that both the 1950X and 1920X slightly beat the i9-7900X. Yet in our tests the result was very different, with Threadripper losing big time, but we used a different encode method - 4K Video to Matroska H.265 MKV 720p30, versus AMD’s 1080p h264 45Mbps to 1080 AppleTV3. We tried three different versions of Handbrake to ensure our results were accurate, but the numbers didn’t change. 

As for game performance, it’s no surprise that Threadripper did not do so well. It lost every single test, as most games only use a maximum of four cores. However, we were able to show the power of multithreading. We ran the 3DMark Cloud Gate test whilst also running the POV-RAY benchmark, and there was almost no performance decrease. This will be great news for those who want to run multiple applications at once, or stream game video without dropping frames – just make sure you have the memory to feed all those cores.

AMD Ryzen Threadripper
5 5
"If you’re a high-end creator who relies upon multi-threaded software, Threadripper is definitely for you."
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