AMD Ryzen 9 6900HX vs AMD Ryzen 9 7940HS

AMD Ryzen 9 6900HX

The AMD Ryzen 9 6900HX is a processor for big (gaming) laptops based on the Rembrandt generation. The R9 6900HX integrates all eight cores based on the Zen 3+ microarchitecture. They are clocked at 3.3 (guaranteed base clock) to 4.9 GHz (Turbo) and support SMT / Hyperthreading (16 threads). The chip is manufactured on the modern 6 nm TSMC process. The "X" in the name indicates the overclocking capabilities of the CPU.

The new Zen 3+ is a refresh of the Zen 3 architecture and should not offer a lot of changes. The chip itself however, offers a lot of new features, like support for USB 4 (40 Gbps), PCI-E Gen 4, DDR5-4800MT/s or LPDDR5-6400MT/s, WiFi 6E, Bluetooth LE 5.2, DisplayPort 2, and AV1 decode.

A big novelty is the integrated GPU Radeon 680M, that is now based on the RDNA2 architecture and offers 12 CUs at up to 2.4 GHz. It should be the fastest iGPU of all at the time of announcement.

Performance

The average 6900HX in our database edges out the Core i7-12800H just slightly while, a little disappointingly, not quite managing to leave the 6900HS behind in the dust. Don't get us wrong; this is still a brilliant CPU for your demanding apps and games, as of late 2022. It does lag behind some of the 12th generation Intel Core i9 options, though.

Thanks to its decent cooling solution and a long-term CPU power limit of nearly 90 W, the XMG Neo 15 2022 is among the fastest laptops built around the 6900HX that we know of. It can be at least 20% faster in CPU-bound workloads than the slowest system featuring the same chip in our database, as of August 2023.

Power consumption

This Ryzen 9 series chip has a default TDP, also known as the long-term power limit, of 45 W with the letter "X" indicating that the user is officially allowed to overclock the thing - leading to an increase in power consumption levels. Either way, a high-performance cooling solution is a must for a CPU like this.

The R9 6900HX is built with TSMC's 6 nm process making for very good, as of early 2023, energy efficiency.

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.