AMD Ryzen 9 8945H vs AMD Ryzen 9 7840HX vs AMD Ryzen 9 7945HX

AMD Ryzen 9 8945H

The Ryzen 9 8945H is a rebadged Ryzen 9 7940HS with higher clock speeds on the Ryzen AI NPU. To be more specific, this is a powerful Hawk Point family laptop chip that has eight Zen 4 cores running at 4.0 GHz to 5.2 GHz. All of its cores are SMT-enabled for a total of 16 processing threads.

Compared to the 8945HS, the H seems to be a local variant for China and offers the same specifications.

The Radeon 780M serves as the integrated graphics adapter.

Architecture & Features

Hawk Point family chips are powered by the Zen 4 architecture, much like Phoenix and Dragon Range family chips are. That's not to say there is no difference between the three. With Hawk Point, AMD is betting big on generative AI; these chips are promised to deliver an up to 40% increase in generative AI performance over 7040 series APUs making apps like DaVinci Resolve and Adobe Photoshop even more powerful.

Unlike Zen 3, Zen 4 features AVX512 support and, thanks to a plethora of other improvements including larger caches/registers/buffers across the board, is slated to bring a double-digit IPC improvement over the former.

Elsewhere, the 8945H has 16 MB of L3 cache and support for super-fast RAM (up to LPDDR5x-7500 or DDR5-5600; no ECC support). The processor is compatible with USB 4 and thus with Thunderbolt; PCIe support is limited to the 4.0 spec for a throughput of 1.97 GB/s per lane. 20 lanes are available.

OS support is limited to 64-bit editions of Windows 11 and Windows 10 and of course to Linux. Note that the chip isn't overclockable and neither is it user-replaceable as it gets soldered down for good (FP7, FP7r2, FP8 socket interfaces).

Performance

The 8945H is an R9 7940HS in disguise, so it's realistic to expect the chip to be just slightly faster than the Core i9-12900HK and also the Ryzen 7 7840HS, as far as multi-thread performance is concerned.

Your mileage may vary depending on how high the CPU power limits are and how competent the cooling solution of your system is.

Graphics

The Radeon 780M has 12 CUs (768 shaders) running at up to 2,800 MHz. This is a very fast iGPU, as of late 2023. It will let you use up to 4 monitors with resolutions as high as SUHD 4320p, and it is also capable of HW-encoding and HW-decoding the most widely used video codecs including AVC, HEVC and AV1. More importantly, it is fast enough for proper 1080p gaming as long as one is fine with low to medium detail settings.

Your mileage may vary depending on how high the CPU power limits are, how competent the cooling solution of the system is, how fast the RAM of the system is (there is no dedicated VRAM here).

Power consumption

This Ryzen 9 series chip has a long-term power limit (default TDP) of 35 W to 54 W, giving laptop makers a choice between longer battery life and higher performance. Either way, an active cooling solution is a must for a system powered by this chip.

The 8945H is built with TSMC's 4 nm process for high, as of late 2023, energy efficiency.

AMD Ryzen 9 7840HX

The chip also integrates 4x USB 3.2 Gen2 (10 Gbps) ports (no USB 4), 28 PCIe 5.0 lanes (for GPUs and SSDs), a dual-channel DDR5-5200 memory controller and a small AMD Radeon 610M graphics card (2CUs, 400 - 2200 MHz).

AMD Ryzen 9 7945HX

The AMD Ryzen 9 7945HX is a fast high-end laptop processor of the Dragon Range series. It offers 16 cores based on the Zen 4 architecture that supports hyperthreading (32 threads). The cores clock from 2.5 (base) up to 5.4 GHz (single core boost). The 7945HX is the fastest mobile Ryzen CPU at launch and derived from the desktop Ryzen 9 7950X.

The Dragon Range series still uses a chiplet design with two CCD-clusters (each with 8 possible cores) in 5nm and an IO-die (including the memory controller and the Radeon 610M iGPU) in 6nm. The chip integrates 4x USB 3.2 Gen2 (10 Gbps) ports (no USB4), 28 PCIe 5.0 lanes (for GPU and SSDs) and a dual-channel DDR5-5200 memory controller.

Performance

The Ryzen 9 7945HX is among the fastest processors in our database, as of August 2023. It is in the same league as the Ryzen 9 7945HX3D and noticeably ahead of the Core i9-13980HX, as far as multi-thread benchmark scores are concerned. It is outrageously, unbelievably fast, and those fortunate enough to purchase a laptop built around this CPU will have no performance issues for at least three years.

Thanks to its powerful cooling solution and a long-term CPU power limit of 128 W, the ROG Strix Scar 17 G733PY-XS96 is one of the fastest laptops built around the 7945HX that we know of.

The R9 7945HX is rated at a TDP of 55 Watt and can be configured up to 75 Watt (cTDP).