Nvidia RTX Spark N1X Battery Life Tests: Surface Laptop Ultra and ProArt P16 Efficiency Compared

What LTT actually measured​

In a 1080p video playback test at 60 Hz and 200 nits, the ProArt lasted about 12 hours and the Surface Laptop Ultra about 9 hours. The MacBook Pro 14 with Apple's M5 Pro also lasted about 9 hours.

The packet's summary of LTT's write-up adds the method and capacities. It also adds a few comparison machines:

I couldn't open LTT's own write-up, so the table figures come from the research summary of it. Notebookcheck's article confirms the headline numbers.

The capacity problem​

Runtime is only half the story. The Surface Laptop Ultra has a battery 27% larger than the MacBook Pro 14's, yet matches its runtime. The ProArt lasted three hours longer than the MacBook but needed a 99.9 Wh battery, about 38% larger. Notebookcheck also points to the Snapdragon X2 Elite Extreme-based Asus Zenbook A16. It lasted 12 hours 40 minutes on a 70 Wh battery in LTT's test. That is a longer runtime than either RTX Spark machine, from a much smaller pack.

Those percentages are plain capacity comparisons. They aren't direct power-draw measurements, and they don't isolate the chip from the display, firmware, and tuning of each laptop.

Heavy load changes the picture​

LTT also ran a stress test with maximum performance profiles. It used the GravityMark 1440p graphics benchmark. The ProArt lasted 1 hour 9 minutes and the Surface 53 minutes. Notebookcheck says the MacBook Pro 14 lasted about 1.5 hours and the Zenbook A16 more than 2 hours, both with smaller batteries.

The research summary also says LTT saw the ProArt cut its available system power as charge dropped. In a Cyberpunk 2077 run, it fell from roughly 108–117 W at high charge to about 60 W by 30%. That detail is LTT's alone and I haven't independently confirmed it. If it holds, "full performance on battery" has a time limit.

Other reviews, other workloads​

Battery numbers depend heavily on the test recipe, and other outlets paint a mixed picture:

• Tom's Guide measured 10:15 of web browsing on the Surface Laptop Ultra. It said the chip doesn't come close to the efficiency of Apple's MacBook Pro.
• Wccftech called the ProArt's endurance respectable, at roughly 14 hours of office productivity and about 3 hours of gaming, but mid-pack for its battery size.
• Notebookcheck's own ProArt review lists the battery runtime as not that great among the few criticisms.
• A roundup from The PC Enthusiast cites independent tests of roughly nine to eleven hours for the Surface.

Don't merge these numbers into one ranking. The tests differ in brightness, workload, and settings.

What this means for buyers​

• Light work: Expect a full workday on either machine. The ProArt has the edge in LTT's playback test.
• GPU-heavy or local AI work: Plan to be near a charger. Both machines ran under 70 minutes in LTT's graphics stress test. The Shortcut's Surface review likewise says local AI mode makes the fans spin full blast and the battery drain quickly.
• Efficiency per watt-hour: Apple and Qualcomm designs currently look better in LTT's tests. That matters if weight and battery size count for you.
• Caveats: These are one lab's results on specific units, run during the launch period. LTT also noted its usual monitoring tools didn't yet fully support RTX Spark. Expect numbers to move as firmware and drivers mature.

Bottom line​

Nine to twelve hours of video is respectable, and none of this makes these laptops bad. They are fast, and the ProArt earns praise for its display. But the efficiency argument for an Arm-based Windows chip is weaker when rivals match or beat the runtime with smaller batteries. Nvidia and its partners can still improve that with updates. Until they do, treat the battery as a convenience for light use, not a license to unplug during heavy work.