Core Ultra X7 358H vs. Core Ultra 7 255H: Panther Lake throttles less and performs more consistently

Intel is debuting Panther Lake-H with two powerful SKUs including the Core Ultra X7 358H and Core Ultra X9 388H each designed to replace the last generation Arrow Lake-H Core Ultra 7 255H and Core Ultra 9 285H, respectively. While the new integrated Arc B390 GPU has been receiving high marks for its huge leap over the Arc 140T/140V series, the gen-over-gen CPU performance benefits have been less significant in comparison. The immediate advantages are nonetheless worth mentioning.

As shown by the comparison graphs below, the Asus ExpertBook Ultra with the Core Ultra X7 performs both faster and more consistently when compared to other 14-inch laptops with the older COre Ultra 7 255H. This means that Turbo Boost clock rates can last for longer periods on the Asus whereas they are more likely to slow over time on Arrow Lake-H subnotebooks. For example, running CineBench R15 xT in a loop would result in relatively consistent scores on the Asus while the same test on the Lenovo Yoga Book 9 14 would result in a performance deficit of almost 25 percent.

The faster and more reliable performance comes with a price, however. When running high loads for extended periods, the Panther Lake CPU in the Asus would plateau at around 89 C to be noticeably warmer than most other 14-inch models where the mid 70 C to mid 80 C range is more common. Additionally, it's no guarantee that future models with Panther Lake can sustain performance as well as the Asus especially since the CPU has been designed to run dynamically at multiple power envelopes to fit multiple screen sizes.

More laptops with Panther Lake are expected to become available during Q2 of this year with the wholly refreshed MSI Prestige family being a notable series. Until then, users can check out our review on the ExpertBook Ultra for more early benchmarks and comparisons.