Monday, September 17th 2018
AMD Ryzen 2000H Series APUs for Mainstream Notebooks Spark TDP Debate Again
AMD introduced the Ryzen 2000H series APUs for mainstream notebooks. These chips are physically identical to the Ryzen 2000U series designed for ultraportable notebooks and convertibles; but come with higher CPU and iGPU clock speeds, and hence a higher TDP. The lineup includes two models for now, the Ryzen 7 2800H, and the Ryzen 5 2600H, both of which are based on the same 14 nm "Raven Ridge" silicon as the Ryzen 2000U series.
The 2800H features a 4-core/8-thread "Zen" CPU, with 512 KB L2 cache per core, and 4 MB of shared L3 cache; with clock speeds of 3.30 GHz, with 3.80 GHz maximum boost. The iGPU is a Radeon Vega 11, with 704 stream processors, and engine clocks of up to 1.30 GHz. If you'll recall, the Ryzen 7 2700U has very similar specifications, but only differs with a lower CPU nominal clock speed of 2.20 GHz (but same boost clocks), and one of the 11 Vega NGCUs being disabled. The difference in TDP between the two chips is enormous - 45W default TDP with configurable TDP as low as 35W for the 2800H; while the 2700U is just 15W default TDP, with configurable TDP as low as 12W.The story repeats with the Ryzen 5 2600H. This chip has the same 4-core/8-thread CPU configuration as its Ryzen 7 counterpart, but with lower CPU clocks, and a slower iGPU that has just 8 NGCUs translating to 512 stream processors, clocked at 1.10 GHz engine clocks. The CPU ticks at 3.20 GHz nominal with 3.60 GHz maximum boost. The Ryzen 5 2500U, again, only has lower nominal clocks at 2.00 GHz, and even has the same iGPU core configuration; but the difference in rated TDP is huge: 45W vs. 15W.
So just how is it that the enabling of a tiny few components or increasing nominal clock speeds have such a tremendous impact on TDP? Perhaps there are other under-the-hood settings these chips have that make them more eager than their U-series siblings. Also, nominal clocks are clock speeds that each of the four CPU cores on the chip are guaranteed to run at, beyond which, depending on a number of factors, the PrecisionBoost algorithm awards higher clocks. On the U-series chips, PrecisionBoost is extremely conservative with boost clocks. Even so, could clock speeds really have such a profound impact on TDP? Join the debate in the comments below.
The 2800H features a 4-core/8-thread "Zen" CPU, with 512 KB L2 cache per core, and 4 MB of shared L3 cache; with clock speeds of 3.30 GHz, with 3.80 GHz maximum boost. The iGPU is a Radeon Vega 11, with 704 stream processors, and engine clocks of up to 1.30 GHz. If you'll recall, the Ryzen 7 2700U has very similar specifications, but only differs with a lower CPU nominal clock speed of 2.20 GHz (but same boost clocks), and one of the 11 Vega NGCUs being disabled. The difference in TDP between the two chips is enormous - 45W default TDP with configurable TDP as low as 35W for the 2800H; while the 2700U is just 15W default TDP, with configurable TDP as low as 12W.The story repeats with the Ryzen 5 2600H. This chip has the same 4-core/8-thread CPU configuration as its Ryzen 7 counterpart, but with lower CPU clocks, and a slower iGPU that has just 8 NGCUs translating to 512 stream processors, clocked at 1.10 GHz engine clocks. The CPU ticks at 3.20 GHz nominal with 3.60 GHz maximum boost. The Ryzen 5 2500U, again, only has lower nominal clocks at 2.00 GHz, and even has the same iGPU core configuration; but the difference in rated TDP is huge: 45W vs. 15W.
So just how is it that the enabling of a tiny few components or increasing nominal clock speeds have such a tremendous impact on TDP? Perhaps there are other under-the-hood settings these chips have that make them more eager than their U-series siblings. Also, nominal clocks are clock speeds that each of the four CPU cores on the chip are guaranteed to run at, beyond which, depending on a number of factors, the PrecisionBoost algorithm awards higher clocks. On the U-series chips, PrecisionBoost is extremely conservative with boost clocks. Even so, could clock speeds really have such a profound impact on TDP? Join the debate in the comments below.