AMD 4900H and 4900HS Ryzen 9 Series 7nm APUs Announced

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Render of an AMD Ryzen 4000 series mobile CPU like the 4900H or 4900HS

AMD have filled out their 2020 mobile lineup with the announcement of the Ryzen 9 4900H and Ryzen 9 4900HS. These new 7nm APUs one-up AMD’s own Ryzen 7 4800H with a better spec on the same “Renoir” silicon.

With a 3.3GHz base clock and max boost up to 4.4GHz, the 45W Ryzen 9 4900H isn’t just AMD’s fastest ever laptop processor – it nips at the heels of their desktop parts. The Ryzen 9 4900HS is a 35W version for more portable systems, coming in at 3GHz base and 4.3GHz boost.

AMD Ryzen 9 4900H and 4900HS Specs

As well as the Renoir-based Ryzen 4000 series mobile lineup, we’ve included the desktop Ryzen 7 3700X in our spec table. This isn’t a perfect comparison because the desktop CPU has significantly more L3 cache, which can have a big impact on both power and performance. Plus, the desktop CPU uses chiplets whereas mobile APUs integrate everything on one die. However, we’re including it because it’s still interesting to see how close the mobile chips are on raw GHz.

Model Cores / Threads Base Clock Max Boost Clock L3 Cache GPU Cores GPU Clock Memory TDP
Ryzen 7 3700X (desktop) 8/16 3.6GHz 4.4GHz 32MB n/a n/a DDR4-3200 65W
Ryzen 9 4900H 8/16 3.3GHz 4.4GHz 8MB 8 1750MHz DDR4-3200, LPDDR4X-4266 45W (35W-54W cTDP)
Ryzen 9 4900HS 8/16 3.0GHz 4.3GHz 8MB 8 1750MHz DDR4-3200, LPDDR4X-4266 35W
Ryzen 7 4800H 8/16 2.9GHz 4.2GHz 8MB 7 1600MHz DDR4-3200, LPDDR4X-4266 45W (35W-54W cTDP)
Ryzen 7 4800U 8/16 1.8GHz 4.2GHz 8MB 8 1750MHz DDR4-3200, LPDDR4X-4266 15W (10W-25W cTDP)
Ryzen 7 4700U 8/8 2.0GHz 4.1GHz 8MB 7 1600MHz DDR4-3200, LPDDR4X-4266 15W (10W-25W cTDP)
Ryzen 5 4600H 6/12 3.0GHz 4.0GHz 8MB 6 1500MHz DDR4-3200, LPDDR4X-4266 45W (35W-54W cTDP)
Ryzen 5 4600U 6/12 2.1GHz 4.0GHz 8MB 6 1500MHz DDR4-3200, LPDDR4X-4266 15W (10W-25W cTDP)
Ryzen 5 4500U 6/6 2.3GHz 4.0GHz 8MB 6 1500MHz DDR4-3200, LPDDR4X-4266 15W (10W-25W cTDP)
Ryzen 3 4300U 4/4 2.7GHz 3.7GHz 4MB 5 1400MHz DDR4-3200, LPDDR4X-4266 15W (10W-25W cTDP)

Full specifications for the AMD Ryzen Mobile 4000 series are available on the AMD website.

A few aspects of these specs are worth briefly diving into, to explain what they mean and what you can take from them.

Max Boost Clock

AMD’s modern processors have a very aggressive, opportunistic boost design. This helps them extract extra performance, but also means the maximum boost numbers may not be hit all that often. You can get an idea of potential responsiveness from the max boost spec. Otherwise, what’s interesting to look at is the base clock, where we see that AMD have the Ryzen 9 4900H more than 10% ahead of the Ryzen 7 4800H at the same TDP.

cTDP

AMD continue to offer a configurable TDP or ‘cTDP’ option. TDP itself stands for Thermal Design Power, and is a specification for how much heat the cooler has to deal with. Since energy is conserved, this also stands in for the amount of electrical power the processor uses. However, unlike electrical power, TDP can be interpreted somewhat flexibly. In long-term load the chip has to limit itself to the TDP, but short-term it can get away with running over TDP and the cooling system won’t be overwhelmed.

Configurable TDP allows TDP to be adjusted in bios, usually by the manufacturer. This means different laptops may perform very differently, but does provide flexibility. Alongside this feature, AMD are promoting their “HS Design Standard” for laptops that unite performance and portability. Laptops meeting AMD’s standards that use the 35W configuration of the 4800H and 4600H will carry the processor names 4800HS and 4600HS respectively.

Memory

A final aspect of the specifications worth pointing out is the memory support. In the past AMD’s lower-power mobile CPUs have been somewhat kneecapped here, for example the Ryzen 7 3700U only supports up to DDR4-2400. DDR4-3200 is a massive 50% improvement in theoretical memory bandwidth. AMD have also added support for LPDDR4 and LPDDR4X at huge transfer rates up to 4266MT/s, on everything from the 4300U to the 4900H.

The LPDDR series is aimed at mobile devices but the faster-moving specification has also raced ahead on bandwidth compared to DDR4. LPDDR has the disadvantage of always being soldered on, but the high performance is very attractive for top-end laptops. It’s important to note that LPDDR4 is the 4th generation of Low Power DDR, not a low power version of DDR4. It would take an entire article to adequately cover all the differences, but suffice to say LPDDR4/4X and DDR4 are not interchangeable.

Performance Claims

In their blog post about the launch, AMD said “We believe that the Ryzen 7 4800H is one of the best gaming notebook processors today beating the i9-9880H in 3DMark Fire Strike Physics (a proxy for how the CPU impacts gaming performance) and content creation applications like Cinebench R20 nT”. The reason AMD are talking about the 4800H here is to put the higher clocked 4900H in context. The performance claim is a bit odd though.

Performance graph showing a 45W 6 core 12 thread intel i7-9750h as a baseline, a 95W 8 core 8 thread intel i7-9700K at +26%, and a 45W 8 core 16 thread amd ryzen 7 4800h at +39%
AMD’s performance claims for the Ryzen 7 4800H

To be clear, we’re not doubting AMD’s numbers. However, Fire Strike Physics isn’t what people might expect a “gaming” benchmark to be. It’s a benchmark of specifically CPU physics, designed to scale up to 32 threads. Games rarely scale so well in practice.

A fair argument might be that AMD expect most laptops to be GPU bound with modern high-end processors. It follows that the test used should be something where a performance problem would be noticeable, not something where all options are fine anyway. We’ll leave it to the reader to make their own mind up on that one.

Regardless of applicability, the numbers being shown off are still impressive. AMD seem to have made a very fast laptop CPU in the 4900H. Retail availability and independent testing are still a while away.

Availability

AMD have described the 4900H and 4900HS as “coming Spring 2020”, so they might still be a few months off yet.

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