Key Takeaways
1. Dual-Chiplet Design: The Xbox Magnus APU features a dual-chiplet architecture with a 144 mm² SoC die for CPU and an advanced 264 mm² GPU die, making it the largest console APU to date.
2. Modular Approach: AMD’s modular strategy allows for shared GPU chiplets between desktop and console, streamlining development and reducing engineering redundancy.
3. Enhanced Features: The APU includes 70 RDNA 5 compute units, a significant increase in L2 cache, and a hybrid CPU design with high-performance and efficiency cores, optimizing it for gaming.
4. Power and Performance Expectations: Estimated power consumption ranges from 250 to 350 W, with potential performance exceeding Sony’s console by 15-30%, targeting 4K 144 Hz gaming.
5. Success Criteria: For Magnus to succeed, it must support backward compatibility, deliver competitive Windows gaming performance, and feature at least 48 GB of GDDR7 memory.
YouTube channel Moore’s Law Is Dead has released a new episode of Broken Silicon that summarizes everything known about AMD’s Magnus APU, which is widely considered to be the chip for Microsoft’s upcoming Xbox. Earlier videos shared bits of information, but the recent episode combines those leaks with new technical insights.
Dual-Chiplet Design
In the update, podcast host Tom describes the Xbox Magnus APU as a dual-chiplet design that connects two dies using advanced bridge packaging. The first die is a 144 mm² SoC die that contains the CPU cores, NPU, and key I/O components, built using TSMC’s N3P process. The second is a larger 264 mm² GPU die, likely manufactured on TSMC’s N3C or N3P node, which includes the GPU logic and another memory controller. Together, they make up 408 mm² of 3 nm silicon, making the Magnus the largest console APU ever made.
Modular Approach
Tom points out that the design reflects AMD’s latest modular strategy, where GPU chiplets are shared between desktop RDNA 5 graphics cards and console platforms. This hardware similarity, he says, should help streamline the development process for both PC and Xbox, while also decreasing AMD’s engineering redundancy.
The GPU section includes 70 RDNA 5 compute units, with 68 enabled in the final retail version. These are spread across four shader engines, three of which have nine workgroups (18 CUs each) and one smaller engine with eight workgroups (16 CUs), resulting in a deliberately uneven layout. During Hot Chips, AMD allegedly discussed this asymmetric design, confirming that RDNA 4 and newer can effectively share memory across uneven shader clusters without hurting performance. The Magnus APU seems to be one of the first real-world examples of this idea.
Enhanced Features
Every shader engine has two arrays, and the GPU is equipped with 24 MB of L2 cache, which is about five times more than what the Xbox Series X has. Although it doesn’t include Infinity Cache, Tom mentions that the larger L2 cache essentially serves a similar role by maintaining bandwidth and enhancing frame stability and ray-tracing performance when paired with the efficient GDDR7.
On the CPU side, Magnus includes three high-performance Zen 6 cores, each expected to reach close to 6 GHz, along with eight Zen 6C efficiency cores. They share 12 MB of L3 cache. While this cache may appear small for an 11-core setup, Tom argues that this hybrid layout is specifically optimized for gaming: a few strong cores take care of the main game threads, while the efficiency cores handle background tasks. This uneven CPU structure reflects current trends in modern PC architectures too.
The APU connects through a 192-bit GDDR7 memory interface, allowing for a configuration of up to 48 GB of unified memory. Of this, 16 GB can be allocated as VRAM and 32 GB as system memory, he explains. This combined pool dynamically shares bandwidth between the CPU and GPU, with Tom emphasizing that anything under 40 GB could limit future game development cycles. The integrated NPU is rated for up to 110 TOPS of compute at 6 W, enabling support for Windows Copilot and AI acceleration features.
Power and Performance Expectations
Power consumption is estimated to be between 250 and 350 W, depending on clock settings, which might require a three-prong power connector like the one used by the PlayStation 3. Tom speculates that Magnus could start production in 2027, coinciding with the anticipated launch of the PlayStation 6 Orion.
Tom claims that based on the specifications, Magnus could outperform Sony’s console by about 15–30 percent, or even up to 35 percent if it ships with higher clock speeds and faster GDDR7 memory. He adds that the Xbox is aimed for 4K 144 Hz gaming, while Sony targets 4K 120 Hz, highlighting Microsoft’s goal of providing a more PC-like gaming experience. However, Tom cautions that this enhanced performance could come with a higher price tag. The use of multiple chiplets, increased power consumption, and advanced packaging might push retail prices into the $1,000–$1,500 range, which is significantly above traditional consoles but still competitive with high-end prebuilt gaming PCs.
Tom concludes that for Magnus to be successful, three criteria need to be met: it must support backwards compatibility across all Xbox generations, provide Windows gaming performance close to SteamOS efficiency, and include at least 48 GB of GDDR7 memory. If these conditions are fulfilled, he believes it could represent a “bridge generation,” a hybrid PC-console that redefines the Xbox experience.
During the episode, viewer inquiries led to further discussion. One viewer asked if RDNA 5 could exceed Nvidia’s Blackwell GPUs in ray-tracing tasks if raster performance was similar. Tom confirmed: “Yes, of course … RDNA 5 should surpass Blackwell that launches in 2025. My AMD sources have been saying since 2022 that RDNA 5 is where AMD focuses on ray tracing. RDNA 4 wasn’t even the real try; they were just trying to catch up.”
A different viewer questioned the potential for 3D V-Cache in consoles. Tom dismissed it, saying that well-optimized console games “don’t require as much cache,” and that RDNA 5 already increases L2 capacity five times over current designs to compensate for bandwidth limitations.
Another viewer inquired if Magnus would include features from PlayStation 6, like Sony’s rumored universal compression tool. Tom suggested that feature equality is highly likely: “I’d expect most features in the PS6 will also be in Magnus, just as most PS5 features were in the Series X. The difference is that Mark Cerny built a better house with the same Lego blocks.” He acknowledged Sony’s hardware team for paying more attention to specialized components like its SSD and I/O controller but argued that both companies fundamentally work from similar AMD building blocks.
Source:
Link
