AMD Ryzen 5 8640HS vs AMD Ryzen 9 8945HS

AMD Ryzen 5 8640HS

The Ryzen 5 8640HS is a mid-range, Hawk Point family processor that was unveiled in Q4 2023. The 8640HS isn't actually a new chip; instead, it's a rebadged Ryzen 5 7640U with a slightly higher wattage as well as higher clock speeds on the Ryzen AI NPU. The 8640HS has 6 SMT-enabled cores (12 threads) running at 3.5 GHz to 4.9 GHz. Those Zen 4 architecture cores are mated to the Radeon 760M integrated graphics adapter.

Architecture & Features

Hawk Point 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 processors are set to deliver an up to 40% increase in generative AI performance over 7040 series APUs.

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

Elsewhere, the 8640HS has 16 MB of L3 cache and USB 4 support (therefore, Thunderbolt is supported as well). The chip is compatible with DDR5-5600 and LPDDR5x-7500 RAM which is still impressive as of late 2023.

A system powered by this Ryzen 5 will have access to twenty PCIe 4 lanes; this means a speedy enough NVMe SSD will be able to deliver speeds up to 7.8 GB/s.

Systems powered by this APU are expected to run 64-bit Windows 11, 64-bit Windows 10, or Linux. Like most laptop chips, the 8640HS is neither overclockable nor user-replaceable. It gets soldered to the motherboard for good (FP7, FP7r2, FP8 socket interfaces).

Performance

It's safe to expect the APU to be at least 15% faster than the Zen 3 Plus-powered Ryzen 5 6600U (6 cores, 12 threads, up to 4.5 GHz), 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 laptop is.

Graphics

The Radeon 760M has 8 CUs (512 shaders) running at up to 2,600 MHz. While not great for gaming (unless you are fine with resolutions such as 900p and low detail settings), the iGPU will let you use up to 4 monitors with resolutions as high as SUHD 4320p. It also HW-decodes and HW-encodes the most widely used video codecs including AV1, HEVC, AVC without breaking a sweat.

Power consumption

The 8640HS has a long-term power limit (default TDP) of 28 W that laptop makers are free to change to anything between 20 W and 30 W. Most companies will probably go for a higher value to get better performance. Either way, an active cooling solution is a must for any system powered by the chip.

Last but not the least, the 8640HS is manufactured on TSMC's 4 nm process for high, as of late 2023, energy efficiency.

AMD Ryzen 9 8945HS

The Ryzen 9 8945HS 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. This APU was brought to life in H2 2023 and all of its cores are SMT-enabled for a total of 16 processing threads.

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