7 nm AMD Ryzen 7 4800U is as fast as the 14 nm Core i9-9880H and at half the TDP, but there's a huge catch

The crown to AMD's latest Zen 2 U-series lineup is the Ryzen 7 4800U. Unlike every other processor in its stack, the octa-core Ryzen 7 4800U is notable for integrating 16 simultaneous execution threads within a 15 W to 25 W power envelope compared to only 8 threads on most other U-series processors. Intel currently has no equal in this regard until you start moving up to its 45 W Core H series CPUs like the 9th gen Core i9-9880H or 10th gen Core i7-10875H. This begs the question: How does the Ryzen 7 4800U compare to the more power-hungry Core i9-9880H?

Apparently, the Ryzen CPU can perform a lot closer to the Core i9-9880H than initially expected based on our time with the 14-inch Lenovo IdeaPad 14 Ultrabook. All tested benchmarks like CineBench, Blender, 7-Zip, GeekBench, HWBOT, and LibreOffice show single-digit percentage points between the Ryzen 7 4800U in our Lenovo and the average Core i9-9880H in our database. No matter how you cut it, these consistent results are impressive for AMD especially when considering the much higher performance-per-watt at play.

It's not a home run for AMD, however, as the limits of the Ryzen 7 4800U are revealed when running extreme loads for long periods with no cooldown period in between. When running CineBench R15 xT in a loop, for example, the initial high score of 1620 points would drop and stabilize to about 1210 points by the 5th or 6th loop. This 25 percent dip in performance is steeper than on any Core i9-9880H laptop we've tested thus far.

The CPU performance drop can be observed in more detail when running Prime95 as well. Clock rates would boost to 3.5 GHz to 4.3 GHz for only the first few seconds before steadily falling and eventually stabilizing at 2.3 GHz and at a core temperature of 60 C to 65 C. Otherwise, core temperature would be well over 90 C according to HWiNFO to suggest that the processor could potentially run faster on larger laptop designs.

Since the Ryzen 7 4800U is so new, we'll have to wait and see what other OEMs can do with the processor outside of Lenovo. Its configurable TDP should allow for a wide range of compatible chassis designs and thus a wide range of performance differences between models.