AMD Ryzen 9 7940HS vs AMD Ryzen 5 7640HS

AMD Ryzen 9 7940HS

The Ryzen 9 7940HS is a powerful Phoenix family APU that saw the light of day in H1 2023. Its 8 cores are powered by the Zen 4 architecture and are SMT-enabled for a total of 16 processing threads. 4.0 GHz is the base clock speed and the highest Boost clock speed achievable is 5.2 GHz.

The 7940HS introduces Ryzen AI which is AMD's answer to Intel's DL Boost and GNA technologies. The Radeon 780M serves as the integrated graphics adapter.

Architecture & Features

Phoenix family chips are powered by the Zen 4 architecture, much like Dragon Range family chips are. The latter however lacks hardware AI workload acceleration capabilities that Phoenix has. Ryzen AI is set to give applications such as DaVinci Resolve and Photoshop quite a bit of generative AI magic.

More importantly, Zen 4 introduces AVX512 support (which Zen 3 chips did not have) 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.

The 7940HS has 16 MB of L3 cache and support for super-fast RAM (up to LPDDR5x-7500 or DDR5-5600, including ECC-enabled memory). 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.

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 average 7940HS in our database is in the same league as the Core i9-12900HK and also, somewhat disappointingly, the Ryzen 7 7840HS, as far as multi-thread benchmark scores are concerned.

Thanks to its decent cooling solution and a long-term CPU power limit of 80 W, the ROG Zephyrus G14 GA402XY is among the fastest laptops built around the 7940HS that we know of. It can be about 15% faster in CPU-bound workloads than the slowest system featuring the same chip in our database, as of August 2023.

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 most video codecs including AVC, HEVC and AV1, but 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).

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 7940HS is built with TSMC's 4 nm process for high, as of late 2023, energy efficiency.

AMD Ryzen 5 7640HS

The Ryzen 5 7640HS is an upper mid-range processor (APU) of the Phoenix product family. It was brought to life in H1 2023 and it has 6 SMT-enabled Zen 4 cores (12 threads) running at 4.3 GHz to 5.0 GHz. The laptop chip is one of the first to feature Ryzen AI, AMD's answer to Intel's DL Boost and GNA technologies. The Radeon 760M iGPU is responsible for carrying out 3D calculations and similar duties.

Architecture & Features

Phoenix family chips are powered by the Zen 4 architecture, much like Dragon Range family chips are. The latter however lacks hardware AI workload acceleration capabilities that Phoenix has.

More importantly, Zen 4 introduces AVX512 support (Zen 3-powered chips did not have that) and, thanks to a plethora of other improvements including larger caches/registers/buffers across the board, is set to bring a double-digit IPC improvement.

Elsewhere, the 7640HS 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 down permanently (FP7, FP7r2, FP8 socket interfaces).

Performance

The average 7640HS in our database is 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 benchmark scores are concerned. This is a good if not record-breaking result as of mid 2023. Such a CPU will handle pretty much any task you can throw at it, gaming included.

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.

Power consumption

The 7640HS 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 this chip.

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