RTX Spark Features Altered Cortex-X925 Cores, Die Analysis Shows Attributes Taken From Dimensity 9400 & Dimensity 9500 Specifically To Tackle PC Workloads

Wccftech's die analysis of NVIDIA's RTX Spark reveals that the superchip's Arm Cortex-X925 CPU cores are not identical to those found in MediaTek's Dimensity 9400 — they have been deliberately altered to handle the demanding sustained workloads of the PC platform. The YouTube channel Geekerwan, known for its detailed silicon analysis, points out that while the RTX Spark's CPU cores are physically smaller than those in MediaTek's previous-generation Dimensity 9400 silicon, they adopt the advanced power rail design and scheduling algorithms from the newer Dimensity 9500's C1-Ultra. This hybrid approach selectively combines attributes from two generations of MediaTek's Arm designs — the efficient core architecture of the Dimensity 9400 with the sophisticated power management of the Dimensity 9500 — to create a CPU subsystem purpose-built for sustained high-performance computing rather than the burst-oriented workloads typical of smartphones.

The key advantage of this customization is thermal headroom: the altered Cortex-X925 cores can maintain higher sustained frequencies without running into thermal limits, a critical requirement for PC workloads that are far more demanding and prolonged than mobile tasks. Microsoft's Surface Laptop Ultra with its 110W TDP demonstrates that sufficient cooling capacity exists in the laptop form factor to handle the heat generation from these boosted clock speeds. However, Wccftech notes there is no confirmation yet on whether individual notebook manufacturers can push clock speeds even higher on their own designs, and final real-world performance will need to be validated through independent benchmarks once RTX Spark laptops ship to reviewers this fall. The analysis also raises an intriguing question: if the thermal envelope on a 110W Surface design handles these boosted cores comfortably, what could ASUS achieve with its 140W-capable RTX Spark notebook configurations?

Beyond the technical details, the die analysis underscores a deeper strategic point: NVIDIA's collaboration with MediaTek has produced more than a simple repurposing of existing smartphone silicon for the PC market. By selectively combining Dimensity 9400's core architecture with Dimensity 9500's power management innovations, RTX Spark represents a genuine customization of Arm IP for the PC form factor — not a rebadged phone chip dropped into a laptop. Wccftech expects this MediaTek partnership to deepen as NVIDIA prepares more advanced versions of the RTX Spark for 2027 and beyond, potentially yielding future Arm CPU cores that are increasingly optimized for Windows workloads from the ground up rather than adapted from MediaTek's mobile designs. For a platform that faced criticism for using cores from what will soon be a two-generation-old smartphone chipset, the die analysis provides the first concrete evidence that NVIDIA's silicon engineering team has done meaningful work to bridge the mobile-to-PC architecture gap.