AMD Ryzen 5 PRO 4650U vs AMD Ryzen 7 7840S

AMD Ryzen 5 PRO 4650U

The AMD Ryzen 5 PRO 4650U is a processor for thin and light laptops based on the Renoir architecture. The 4650U integrates six cores based on the Zen 2 microarchitecture. They are clocked at 2.1 (guaranteed base clock) to 4 GHz (Turbo) with SMT for a total of 12 threads. The chip is manufactured on the modern 7 nm TSMC process and partly thanks to it AMD advertises a 2x improved performance per Watt for the Renoir chips.

The PRO processors offer a range of business features like hardware security (e.g., AMD Memory Guard), manageability (e.g., support for Microsoft Endpoint Manager), and longer availability and software stability.

In addition to the six CPU cores, the APU also integrates a Radeon RX Vega 6 integrated graphics adapter with 6 CUs at up to 1500 MHz. The dual channel memory controller supports DDR4-3200 and energy efficient LPDDR4-4266 RAM. Furthermore, 8 MB level 3 cache can be found on the chip. See our hub page on the Renoir Processors for more information.

Performance

The average 4650U in our database is just as fast as the Intel Core i7-11375H and the AMD Ryzen 5 4600U are in multi-thread workloads. This is a fairly decent mid-range CPU, as of late 2021.

Your mileage may vary depending on how high the CPU power limits are and how competent the cooling solution of your system is.

Power consumption

This Ryzen 5 series chip has a default TDP (also known as the long-term power limit) of 15 W. Which is a tad too high to allow for passively cooled designs, besides, laptop makers aren't really obliged to stick to it.

The AMD Ryzen 5 PRO 4650U is manufactured on TSMC's 7 nm process, leading to average, as of mid 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.