AMD Ryzen 9 7945HX vs AMD Ryzen 7 5825U

AMD Ryzen 9 7945HX

The AMD Ryzen 9 7945HX is a fast high-end laptop processor of the Dragon Range series. It offers 16 cores based on the Zen 4 architecture that supports hyperthreading (32 threads). The cores clock from 2.5 (base) up to 5.4 GHz (single core boost). The 7945HX is the fastest mobile Ryzen CPU at launch and derived from the desktop Ryzen 9 7950X.

The Dragon Range series still uses a chiplet design with two CCD-clusters (each with 8 possible cores) in 5nm and an IO-die (including the memory controller and the Radeon 610M iGPU) in 6nm. The chip integrates 4x USB 3.2 Gen2 (10 Gbps) ports (no USB4), 28 PCIe 5.0 lanes (for GPU and SSDs) and a dual-channel DDR5-5200 memory controller.

Performance

The Ryzen 9 7945HX is among the fastest processors in our database, as of August 2023. It is in the same league as the Ryzen 9 7945HX3D and noticeably ahead of the Core i9-13980HX, as far as multi-thread benchmark scores are concerned. It is outrageously, unbelievably fast, and those fortunate enough to purchase a laptop built around this CPU will have no performance issues for at least three years.

Thanks to its powerful cooling solution and a long-term CPU power limit of 128 W, the ROG Strix Scar 17 G733PY-XS96 is one of the fastest laptops built around the 7945HX that we know of.

The R9 7945HX is rated at a TDP of 55 Watt and can be configured up to 75 Watt (cTDP).

AMD Ryzen 7 5825U

The AMD Ryzen 7 5825U is a processor for thin and light laptops based on the Cezanne generation. It is part of the "Barcelo" refresh in early 2022 and offers 100 MHz higher clocked CPU cores compared to the old Ryzen 7 5800U. The R7 5825U integrates all eight cores based on the Zen 3 microarchitecture and is the fastest U-series processor at launch. They are clocked at 2 (guaranteed base clock) to 4.5 GHz (Turbo) and support SMT / Hyperthreading (16 threads). The chip is manufactured on the modern 7 nm TSMC process.

The new Zen 3 microarchitecture offers a significantly higher IPC (instructions per clock) compared to Zen 2. For desktop processors AMD claims 19 percent on average and in applications reviews showed around 12% gains at the same clock speed.

Performance

The average 5825U in our database is in the same league as the Ryzen 7 7735U and the Core i7-1270P, as far as multi-thread benchmark scores are concerned. Which is a really good result, as of early 2023.

Thanks to its decent cooling solution and a long-term CPU power limit of 37 W, the 2022 Envy x360 15 is among the fastest laptops built around the 5825U that we know of. It can be more than 15% faster in CPU-bound workloads than the slowest system featuring the same chip in our database, as of August 2023.

In addition to the eight CPU cores, the APU also integrates a Radeon RX Vega 8 GPU with 8 CUs at up to 2000 MHz. The dual channel memory controller supports DDR4-3200 and energy efficient LPDDR4-4266 RAM. Furthermore, 16 MB level 3 cache (up from 8 MB at the 4800U) can be found on the chip.

The TDP of the APU is specified at 15 Watt (default) and can be configured from 10 to 25 Watt by the laptop vendor (most chips are configured higher than 15 Watt). That means the chip is intended for thin and light laptops (but with fans).