A prototype of Microsoft’s forthcoming Surface Laptop Ultra has surfaced in the hands of an independent reviewer, offering the first detailed look at Nvidia’s RTX Spark N1X system-on-chip in a laptop form factor. The device, marked as an EV1.5 engineering validation unit, represents the closest the public has come to testing Nvidia’s consumer Arm processor more than a year after the chip was first announced.
The reviewer, posting on the TechPowerUp forum under the username Fouquin, claimed to have acquired the prototype through unofficial channels. The machine is a 38-centimeter (15-inch) laptop with a milled aluminum chassis comparable to Apple’s MacBook Pro, housing Nvidia’s top-end RTX Spark N1X SoC built on the Blackwell architecture. The chip features 20 Arm CPU cores including high-performance X925 cores and 6,144 CUDA cores, paired with 24 gigabytes of unified memory in the entry configuration and support for up to 128 gigabytes.
What makes the RTX Spark architecture distinctive is its power delivery model. Nvidia has long claimed that its Arm-based laptop SoC could deliver identical graphics performance whether running on battery or plugged into the wall, a feat that Intel and AMD-based laptops have never achieved due to the power constraints of x86 platforms. The prototype largely validated this claim: benchmarks showed matching GPU scores in both modes, a significant differentiator for the Windows-on-Arm ecosystem.
The performance figures tell a mixed story. In Cinebench 2024, the RTX Spark scored 1,386 points in multi-core and 123 in single-core. Blender renders completed in one minute and 38 seconds for the BMW27 scene and 18 minutes and 28 seconds for the more demanding Barbershop scene. These results trail Apple’s M5 Pro in equivalent MacBooks, a gap the reviewer attributed to immature drivers and pre-release firmware rather than fundamental hardware limits.
The prototype exhibited several issues consistent with early engineering hardware. Random lockups occurred after approximately one hour of sustained use. CUDA compute workloads failed to complete, returning zero-sum results as GPU power suddenly dropped to zero watts. Rhythmic six-second stutters affected gaming performance. The display, a 3,270-by-2,180-pixel LG panel with local dimming, showed problematic zone behavior and non-functional G-Sync.
Driver updates compounded some problems. Starting with November 2025 drivers, the reviewer upgraded to a developer preview build version 616.00 supporting CUDA 13.4. The new drivers did not improve gaming performance and increased idle power draw from seven to eight watts up to 12 to 23 watts.
The keyboard earned praise as the best option outside of a MacBook, with stiff rubber dome switches and camera-based automatic backlight adjustment. The haptic touchpad showed one to two seconds of input lag on the prototype, a likely fix for the retail version. The SSD is user-replaceable, a rarity in premium ultrabooks.
Pricing estimates from the reviewer place the entry-level 24-gigabyte, 512-gigabyte configuration at roughly $2,799, with the 128-gigabyte halo configuration reaching approximately $4,499. Nvidia has partnered with Sega for native game support, including the upcoming Virtua Fighter Crossroads title scheduled for 2027.
The RTX Spark shares physically identical silicon with Nvidia’s DGX Spark, a developer-focused machine that has already begun shipping. The consumer RTX Spark variant has taken longer to reach production, a delay the reviewer speculated may stem from Nvidia prioritizing the higher-margin developer market. A retail launch is expected in the fall of 2026.
Sources: Mystery reviewer puts Nvidia RTX Spark prototype through its paces (Tom’s Hardware, Jul 28); Nvidia RTX Spark N1X benchmarked in Surface Laptop Ultra (TechSpot, Jul 28); Fouquin’s TechPowerUp review thread (TechPowerUp, Jul 26)