AMD Ryzen 7 6800U vs AMD Ryzen 5 7640HS vs AMD Ryzen 7 7840S

AMD Ryzen 7 6800U

The AMD Ryzen 7 6800U is a processor for thin and light laptops based of the Rembrandt generation. The R7 6800U integrates all eight cores based on the Zen 3+ microarchitecture. They are clocked at 2.7 (guaranteed base clock) to 4.7 GHz (Turbo) and support SMT / Hyperthreading (16 threads). The chip is manufactured on the modern 6 nm TSMC process. Compared to the similar R7 6800H, the 6800U offers a lower base clock speed and a lower TDP.

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 2.2 GHz. It should be the fastest iGPU of all at the time of announcement.

Performance

The average 6800U in our database easily shoulders its way towards the best of the best, trading blows with the Core i7-1270P, the Core i7-11850H and the Ryzen 7 PRO 6850H as far as multi-thread benchmark scores are concerned. Throw everything you can at this little guy. He'll take it all and ask for more.

Thanks to its decent cooling solution and a long-term CPU power limit of more than 20 W, the Mercury EM680 is among the fastest systems built around the 6800U 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 7 series chip has a default TDP, also known as the long-term power limit, of 15 W to 28 W, the expectation being that laptop makers will go for a higher value in exchange for higher performance. Either way, a proper cooling solution is a must.

The R7 6800U is manufactured on the 6 nm TSMC process for higher-than-average, as of mid 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.

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.