AMD Ryzen 5 8640HS vs AMD Ryzen 5 8645HS

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 5 8645HS

The Ryzen 5 8645HS is an upper mid-range processor (APU) of the Hawk Point family. This isn't an entirely new chip; instead, the 8645HS is a rebadged Ryzen 5 7640HS with higher clock speeds on the Ryzen AI NPU. The 8645HS was brought to life in Q4 2023 and it has 6 SMT-enabled Zen 4 cores (12 threads) running at 4.3 GHz to 5.0 GHz. The Radeon 760M iGPU is responsible for carrying out 3D calculations and similar duties.

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 8645HS has 16 MB of L3 cache and a super-fast DDR5-5600 / LPDDR5x-7500 RAM controller. USB 4 (and thus Thunderbolt) is supported natively and so is PCIe 4. In fact, 20 PCIe 4 lanes are on offer; data transfer speeds of up to 7.8 GB/s will be possible provided a sufficiently fast NVMe SSD is used.

Systems powered by this Ryzen 5 series chip are expected to run 64-bit Windows 11, 64-bit Windows 10, or Linux. Please note that the APU is not overclockable and neither will you be able to replace it with a faster one as it gets soldered to the motherboard permanently (FP7, FP7r2, FP8 socket interfaces).

Performance

Since the 8645HX is an 7640HS in disguise, it is safe to expect the APU to be about as fast as the Ryzen 9 5900HX, Ryzen 7 6800H, Ryzen 7 7736U and also the Core i5-12500H, 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 760M has 8 CUs (512 shaders) running at up to 2,600 MHz. While this is not the best graphics adapter for gaming as it's only just fast enough for low quality settings and resolutions such as 1600 x 900, it will let you connect up to four SUHD 4320p monitors and it also HW-encodes and HW-decodes the most widely used video codecs such as AV1, HEVC and AVC without breaking a sweat.

Power consumption

The 8645HS has a long-term power limit (default TDP) of 35 W to 54 W, giving laptop makers a choice between improving battery life and giving the system they are working on more oomph. Either way, an active cooling solution is a must for any system powered by the chip.

This Ryzen 5 series APU is built with TSMC's 4 nm process for high, as of late 2023, energy efficiency.