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Immortalis-G925 vs. Mali-G720 & G715: Architecture, Ray Tracing & DVS Analysis

Immortalis-G925 vs. Mali-G720 & G715 Architecture, Ray Tracing & DVS Analysis

Mobile silicon has hit a hardware ceiling. For years, simply adding more cores to the Mali series resulted in diminishing returns due to the “Bandwidth Wall”—where system memory couldn’t feed the shaders fast enough.

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The shift from the brute-force Mali-G710 to the efficiency-focused Immortalis-G720 marked the first real solution: Deferred Vertex Shading (DVS). Now, the Immortalis-G925 pushes further with Fragment Prepass and desktop-class Ray Tracing logic.

This report examines the silicon-level changes defining the Dimensity 9400 and 9300, stripping away marketing terms to measure raw rasterization, thermal sustainability, and the real impact of moving from software ray queries to hardware Lumen support.

Arm GPU Deep Dive: Immortalis-G925 vs Mali Series | Faceofit
Tech Deep Dive Updated Dec 2025

The Silicon Canvas.
Immortalis-G925 vs. The World.

Arm’s mobile graphics just hit the “Cortex-X” moment. We analyze the aggressive shift from the Bandwidth Wall of G710 to the ray-tracing powerhouse of G925.

Performance Trajectory

Relative rasterization gains in flagship implementations (Dimensity 9000 to 9400).

Source: Faceofit Analysis Lab

The Mobile Graphics Shift

Mobile graphics have moved past simple thermal constraints. We now operate in a paradigm where desktop features like hardware ray tracing and mesh shading define the flagship experience. The driving force is the “Bandwidth Wall.” As resolutions standardized at 1440p and 120Hz, traditional pipelines failed to feed shader cores without choking system memory.

Architecture Evolution

2021 • Valhall 3
Mali-G710

Introduced Command Stream Frontend (CSF) to reduce CPU driver overhead. Pure rasterization focus.

2022 • Valhall 4
Immortalis-G715

First hardware Ray Tracing Unit (RTU). Bifurcation of Mali (Non-RT) and Immortalis (RT).

2023 • 5th Gen
Immortalis-G720 & G725

Deferred Vertex Shading (DVS) solves the bandwidth crisis. G725 appears as the sub-premium variant.

2024/25 • 5th Gen Advanced
Immortalis-G925

Fragment Prepass and Cortex-X style performance targeting. 50% faster Ray Tracing.

1. The Bandwidth Solution: G720’s DVS

Before the G720, GPUs relied on “Immediate Mode” or simple tiling. The 5th Gen architecture introduced Deferred Vertex Shading (DVS).

In high-geometry games like Genshin Impact, older GPUs (G710/G715) would process geometry, write it to main RAM, and read it back for texturing. This round-trip killed battery life. DVS keeps that intermediate geometry data on the GPU silicon itself.

  • Bandwidth Impact: Reduces system memory traffic by up to 40%.
  • Result: Allowed the Dimensity 9300 to run sustained high FPS without thermal throttling.

2. Silicon Floorplan: Inside the Core

The shift from Valhall (G715) to 5th Gen (G720/G925) wasn’t just about Ray Tracing; it changed how the Execution Engines (EE) handle math.

The Dual-Issue Architecture

In previous generations, the ALU (Arithmetic Logic Unit) pipelines were rigid. In G925, the cores act as “Dual-issue” machines. They can process two distinct math operations per clock cycle if the instructions are compatible.

G710 Core
G925 Core
Parallel FP32 Operations

3. Ray Tracing: G715 vs. G925

The G715 brought Ray Tracing to hardware, but the G925 makes it usable for complex global illumination.

Feature Immortalis-G715 Immortalis-G925
RT Implementation Basic Hardware RTU Gen 2 Hardware RTU
Primary Usage Soft Shadows, Simple Reflections Lumen (UE5), Global Illumination
Intersection Engine Standard Double Throughput for Complex Geometry
Performance Delta Base +52% Faster

4. Beyond Pixels: AI & Machine Learning

While NPUs (like Google’s TPU or MediaTek’s APU) handle heavy AI lifting, the GPU plays a crucial role in real-time inference during gaming, such as DLSS-style upscaling (FSR or MetalFX equivalents).

Matrix Multiply Enhancements

The G710 introduced dedicated instructions for Matrix Multiplication (MatMul). The G925 significantly expands this with optimized support for Int8 and Int16 precision. This allows camera pipelines to use the GPU for advanced noise reduction and “Magic Eraser” style effects directly in the viewfinder stream, unloading the main CPU.

5. Sustained Performance & Thermals

Peak performance is a marketing number; sustained performance is the user reality. The chart below illustrates how the architecture manages heat dissipation over a 20-minute gaming session.

The G710 (Red line) starts strong but throttles aggressively after 4 minutes. The G925 (Blue line) maintains 85% of its peak performance due to the bandwidth savings from DVS and Fragment Prepass.

6. Variable Rate Shading (VRS) Explained

VRS allows the GPU to reduce visual fidelity in areas where the user isn’t looking—such as the corners of the screen or fast-moving blurred objects—while maintaining 4K clarity in the center.

Standard Rendering (1×1)

Every pixel is calculated individually. High cost, high quality.

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VRS Tier 2 (2×2)

Four pixels share one color calculation. 75% less shading work.

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Technical Specifications Matrix

A comprehensive breakdown across five generations of Arm graphics architecture.

Specification Mali-G710 Mali/Imm-G715 Mali-G725 Imm-G720 Imm-G925
Architecture Valhall 3 Valhall 4 5th Gen 5th Gen 5th Gen Adv.
Ray Tracing None HW Gen 1 Optional (Rare) HW Gen 1 HW Gen 2
VRS Support No Tier 1 Tier 2 Tier 2 Tier 2
Geometry Traditional Traditional DVS DVS DVS + Prepass
AI Support FP16 FP16/MatMul Int8/Int16 Int8/Int16 Adv. Matrix
Max Cores 16 16 9 16 24

Technical Glossary

AFBC (Arm Frame Buffer Compression)

A lossless compression format that reduces the size of textures and colors moving between the GPU and memory, saving battery.

Overdraw

Wasted effort when the GPU draws pixels for an object that is immediately covered up by another object (like a wall covering a chair).

Lumen

Unreal Engine 5’s global illumination system. It requires heavy hardware ray tracing support, which G925 enables on mobile.

CSF (Command Stream Frontend)

A small microcontroller inside the GPU that handles scheduling, so the main Android CPU doesn’t have to micromanage the graphics card.

Common Questions

Is the Mali-G725 just a rebranded G720?

It is architecturally identical (5th Gen) but segmented differently. The G720 is the “Immortalis” tier, meaning it mandates Ray Tracing hardware and supports high core counts (10+). The G725 is the “Mali” tier, usually capped at 9 cores and typically shipped without Ray Tracing units to lower costs for mid-range phones.

Why does the Pixel 9 use Mali-G715 instead of G720?

Google’s Tensor chips often trail the latest Arm IP by one generation due to their custom design cycle. While the Pixel 8 and 9 series use competent GPUs, they often opt for the “Mali” configuration (lower core count, no RTU) to prioritize die space for their NPU (AI Neural Core).

Can G925 play PC games via emulation?

Yes. The G925’s support for advanced Vulkan extensions and its high raw rasterization performance makes it the best current Android GPU for Windows emulation (via Winlator or Mobox), outperforming the Adreno 750 in raw shader throughput, though driver compatibility varies.

What is the ‘Bandwidth Wall’?

This refers to the limitation where the GPU is fast enough to render a scene, but the system memory (RAM) is too slow to send it the necessary texture and geometry data. The G720 and G925 solve this with DVS (Deferred Vertex Shading), which keeps data inside the GPU cache, bypassing the slow trip to main RAM.

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