AMD Ryzen 7 7840HS vs AMD Ryzen 7 7840S vs AMD Ryzen 9 7940HS

AMD Ryzen 7 7840HS

The Ryzen 7 7840HS is a powerful Phoenix family chip that saw the light of day in H1 2023. The processor features 8 cores (16 threads thanks to SMT support) running at 3.8 GHz. The highest Boost clock speed achievable is 5.1 GHz.

Not only does this APU has full might of the Zen 4 architecture at its disposal, it also comes with the new Ryzen AI technology that's set to make generative AI more ubiquitous than ever before. Last but not the least, the Radeon 780M serves as the integrated GPU.

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 coming after Intel's DL Boost and GNA technologies; time will tell if this move by AMD is a good idea.

Perhaps 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 set to bring a double-digit IPC improvement.

Elsewhere, the 7840HS has 16 MB of L3 cache and a seriously fast RAM controller (up to LPDDR5x-7500 and up to DDR5-5600, ECC-enabled memory included). PCI-Express speeds are capped at 1.97 GB/s per lane which corresponds to the 4.0 spec.

This Ryzen 7 series chip is designed to run 64-bit Windows 11, 64-bit Windows 10 or Linux; please note that it isn't overclockable and neither is it user-replaceable. It gets soldered down for good instead (FP7, FP7r2, FP8 socket interfaces).

Performance

The average 7840HS in our database is in the same league as the Core i7-12700H, Core i7-12850HX, Core i9-12900H, Core i9-13900H and also the Ryzen 9 7940HS, as far as multi-thread benchmark scores are concerned. This is a very fast chip, as of Q3 2023.

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 (12 CUs / 768 shaders, up to 2,700 MHz) is capable of powering 4 monitors simultaneously with resolutions as high as SUHD 4320p. It will also have little issue hardware-encoding and hardware-decoding the most widely used video codecs (AV1, HEVC, AVC). As far as gaming is concerned, the thing will let you play most games at 1080p as long as you are fine with moderate quality settings. Long story short, this is the best iGPU money can buy, as of H2 2023.

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

Power consumption

This Ryzen 7 series chip has a long-term power limit (default TDP) of 35 W to 54 W, giving system makers a choice between improving battery life and making the system they're designing insanely fast. Either way, an active cooling solution is a must for a laptop or a mini-PC built around this APU.

The 7840HS is built with TSMC's 4 nm process for high, as of late 2023, energy efficiency.

AMD Ryzen 7 7840S

The AMD Ryzen 7 7840S is a fast high-end laptop processor of the Phoenix series. It offers 8 cores (octa core) based on the Zen 4 architecture that supports hyperthreading (16 threads). The cores clock from 3.8 (base) up to 5.1 GHz (single core boost). The processor includes 8 MB L2 cache and 16 MB L3 cache. The processor is exclusively available in Lenovo laptops but the specs are similar to the regular Ryzen 7 7840HS.

The performance of the R7 7840S is only slightly below the fastest model, the R9 7940HS, as the clock speed difference is only minimal (e.g. -100 MHz / 2% slower single core boost). Therefore, the CPU should also perform slightly higher than the old top model Ryzen 9 6980HX (8 Zen 3 cores with up to 4.9 GHz) at 54W TDP and Ryzen 9 6980HS at 35W TDP. Compared to the higher end Dragon Range series, the 7840HS should be similar to the Ryzen 7 7745HX (also 8 Zen 4 cores, max 5.1 GHz, 55W TDP, 32 MB L3).

The chip integrates a modern and fasts RDNA 3 graphics card (iGPU) called Radeon 780M with 12 CUs and up to 2.7 GHz clock speed. Furthermore, the Phoenix series include a video engine with AV1 de- and encoding, a new Xilinx FPGA based XDNA AI accelerator (Ryzen AI) that should be faster than the AI engine in the Apple M2 SOC and a dual-channel DDR5-5600 / LPDDR5x-7500 memory controller (with ECC support). The connectivity features includes 2 possible USB 4 (40 Gbps) ports and 20 PCIe 4.0 lanes for a GPU and SSDs.

The Phoenix series uses a single monolithic design (unlike the chiplet design of the 7045HX series) and is manufactured in the modern 4nm process at TSMC. The TDP can be configured between 35 and 45 Watt.

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.