AMD Ryzen 7 8840HS vs Intel Core i7-1255U vs AMD Ryzen 7 8745HS

AMD Ryzen 7 8840HS

The Ryzen 7 8840HS is a powerful processor (APU) of the Hawk Point family. This isn't an entirely new laptop chip; instead, it's a rebadged Ryzen 7 7840U with a slightly higher wattage as well as higher clock speeds on the Ryzen AI NPU. The 8840HS has eight Zen 4 cores running at 3.3 GHz to 5.1 GHz that are SMT-enabled for a total of 16 processing threads, while the great Radeon 780M is responsible for 3D processing and similar duties.

Architecture & Features

Hawk Point family chips are powered by the Zen 4 architecture, much like Phoenix and Dragon Range family chips are. That's not to say there is no difference between the three. With Hawk Point, AMD is betting big on generative AI; these processors are set to deliver an up to 40% increase in generative AI performance over 7040 series APUs, making apps like DaVinci Resolve and Adobe Photoshop more useful than ever before.

Unlike Zen 3, Zen 4 features AVX512 support and, thanks to a plethora of other improvements including larger caches/registers/buffers, is slated to bring a double-digit IPC improvement over the former.

Elsewhere, the 8840HS has 16 MB of L3 cache and support for super-fast DDR5-5600 and LPDDR5x-7500 RAM. The chip is compatible with USB 4 and therefore with Thunderbolt. It comes with 20 PCIe 4 lanes, giving NVMe SSDs up to 7.8 GB/s of throughput.

Systems built around this Ryzen 7 series APU are designed to run 64-bit Windows 11, 64-bit Windows 10, or Linux. Please note that this processor is not overclockable and neither is it user-replaceable. It gets soldered down for good instead (FP7, FP7r2, FP8 socket interfaces).

Performance

Since this is a 7840U in disguise that we are dealing with here, it is safe to expect the 8840HS to be about as fast as the Core i7-12650H, as far as multi-thread performance is concerned.

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

Graphics

The Radeon 780M has 12 CUs (768 shaders) purring away at up to 2,700 MHz. This is exactly the right iGPU for people looking for a bit more horsepower than what Intel's aging Xe options can provide. The Radeon will let you use up to 4 monitors with resolutions as high as SUHD 4320p and it will also HW-decode and HW-encode the most widely used video codecs (including AV1, HEVC and AVC) without breaking a sweat. In terms of gaming, the thing is good enough for 1080p and medium-to-low settings, as of late 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 28 W that laptop makers are free to tune to their liking, with values between 20 W and 30 W greenlighted by AMD. Either way, an active cooling solution is a must for any system powered by this chip.

The 8840HS is built with TSMC's 4 nm process for high, as of late 2023, energy efficiency.

Intel Core i7-1255U

The Intel Core i7-1255U is a high-end mobile CPU for thin and light laptops based on the Alder Lake architecture. It was announced in early 2022 and offers 2  performance cores (P-cores, Golden Cove architecture) and 8 efficient cores (E-cores, Gracemont architecture). The P-cores support Hyper-Threading leading to 12 supported threads when combined with the E-cores. The clock rate ranges from 1.7 to 4.7 GHz on the performance cluster and 1.2 to 3.5 GHz on the efficient cluster. The performance of the E-cores should be similar to old Skylake cores (compare to the Core i7-6700HQ). All cores can use up to 12 MB L3 cache. Compared to the i7-1265U (fastest U-series CPU at launch), the 1255 offers 100 MHz lower clocked CPU cores and only "Essentials" vPro management features. Compared to the P-series (28W) or H-series (45W), the 15W TDP may limit the sustained performance.

Performance

The average 1255U in our database is in the same league as the Ryzen 5 5600U, as far as multi-thread benchmark scores are concerned. Which is nothing to be ashamed of, as of mid 2023.

Thanks to its decent cooling solution and a long-term CPU power limit of 28 W, the Spectre x360 13.5 14t-ef000 is among the fastest laptops built around the 1255U that we know of. It can be 20% faster in CPU-bound workloads than the slowest system featuring the same chip in our database, as of August 2023.

Architecture

The integrated memory controller supports various memory types up to DDR5-4800, DDR4-3200, LPDDR5-5200, and LPDDR4x-4267. The Thread Director (in hardware) can support the operating system to decide which thread to use on the performance or efficient cores for the best performance. For AI tasks, the CPU also integrates GNA 3.0 and DL Boost (via AVX2). Quick Sync in version 8 is the same as in the Rocket Lake CPUs and supports MPEG-2, AVC, VC-1 decode, JPEG, VP8 decode, VP9, HEVC, and AV1 decode in hardware. The CPU only supports PCIe 4.0 (x8 for a GPU and two x4 for SSDs).

The integrated graphics card is based on the Xe-architecture and offers all 96 EUs (Execution Units) operating at up to 1.25 GHz.

Power consumption

This Core i7 has a "minimum assured" power consumption of 12 W. Its Base power consumption sits at 15 W and its maximum Intel-recommended Turbo power consumption isn't supposed to exceed 55 W. All those values are too high to allow for pasisvely cooled designs.

Last but not the least, Core i7-1255U is built with Intel's fourth-gen 10 nm process marketed as Intel 7 for decent, as of late 2022, energy efficiency.

AMD Ryzen 7 8745HS

The Ryzen 7 8745HS is a China-only Hawk Point family chip that never received an official launch. Targeted at gaming and productivity laptops but widely used in mini-PCs, too, the 8745HS features 8 cores (16 threads thanks to SMT support) running at up to 4.9 GHz, along with the still fairly capable Radeon 780M iGPU. There is no NPU here.

As an APU meant for use within China, this Ryzen 7 should be fully compliant with the Chinese government-approved cryptography standards.

The only difference between the 8745HS and the 8745H is the slightly lower default wattage of the latter, potentially leading to slightly lower clock speeds.

Performance

We fully expect this Zen 4 architecture processor to be about as fast as the Ryzen 7 7745HX (8 Zen 4 cores, 3.6 GHz to 5.1 GHz) meaning its multi-thread performance is a little better than the Core Ultra 9 185H but a few percentage points behind the Ryzen AI 9 HX 370.

Architecture and Features

Unlike Zen 3, Zen 4 features AVX512 support along with other improvements, like larger caches/registers/buffers across the board. Elsewhere, the 8745HS has 16 MB of L3 cache and a fast RAM controller (up to LPDDR5x-7500 and up to DDR5-5600). There are 20 PCI-Express 4 lanes for connecting devices such as NVMe SSDs (1.97 GB/s per lane) and graphics cards; USB 4 / Thunderbolt support is onboard, too. Please note that the APU isn't overclockable and neither is it user-replaceable. It gets soldered on to the motherboard for good (FP7r2 or FP8 socket interfaces).

Graphics

The Radeon 780M (12 CUs / 768 shaders, up to 2,600 MHz) can drive 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, AVC, HEVC). As far as gaming is concerned, many titles are still playable at 1080p as of early 2025 albeit with most settings dialed down do Lowest or Low.

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 faster. Either way, an active cooling solution is a must for a laptop or a mini-PC built around this APU.