ATI Mobility Radeon HD 4870

The ATI Mobility Radeon HD 4870, built on AMD’s TeraScale architecture and the 55 nm process at TSMC, represents a specific moment in mobile graphics where desktop-class performance was attempted in a modular MXM form factor. With a die size of 256 mm² housing 956 million transistors, this chip delivers a peak FP32 throughput of 880.0 GFLOPS, a texture rate of 22.00 GTexel/s, and a pixel rate of 8.800 GPixel/s, positioning it as a high-end part for its 2009 release window.

Benchmark Performance

The benchmark data shows that the Mobility Radeon HD 4870 sits at the 50th percentile among all GPUs, indicating a median performance tier when viewed against the entire historical database. However, the absence of specific benchmark scores and nearest rival entries in the fact pack means that direct percentage comparisons against contemporary competitors are not available from this dataset. The average benchmark score is listed as 0, which underscores the lack of quantitative performance data for this specific mobile part.

What can be analyzed is the theoretical throughput. The 880.0 GFLOPS FP32 figure places this GPU firmly in the upper echelon of mobile graphics for its generation, though without rival scores, its relative standing cannot be precisely quantified. The 22.00 GTexel/s texture fill rate suggests strong capability for pixel-dense scenes, while the 8.800 GPixel/s pixel rate indicates a ceiling for fill-rate-bound workloads at high resolutions. The 800 shading units, operating under the TeraScale architecture, provide the raw compute for shader-heavy effects, but the architecture’s lack of unified shader improvements seen in later designs means efficiency is lower than modern parts.

The memory clock of 888 MHz, translating to 1776 Mbps effective, is a critical factor. This is a standard GDDR3 speed for the era, and when combined with the 256-bit bus, yields a bandwidth of 56.83 GB/s. This bandwidth figure is moderate by modern standards but was competitive for high-end laptops at launch. The interaction between the 880.0 GFLOPS compute and 56.83 GB/s bandwidth creates a balanced pipeline for 2009-era games, but it is not a configuration that scales gracefully to higher resolutions or texture-heavy workloads, as the bandwidth becomes a limiting factor relative to the compute capacity.

Who Should Consider It

Given the performance metrics, this GPU is best suited for gaming at 1366x768 or 1600x900 resolution with medium to high settings in titles released around its launch generation. The 880.0 GFLOPS of FP32 compute is sufficient for DirectX 10.1 era titles, which typically had lower geometric complexity and simpler shader programs compared to later DirectX 11 or 12 games. For 1280x720 resolution, the 8.800 GPixel/s pixel rate and 22.00 GTexel/s texture rate are adequate to maintain playable frame rates in most contemporary titles, provided texture quality is not maxed out.

At 1920x1080, the data suggests this GPU would struggle with high settings due to the 56.83 GB/s memory bandwidth being insufficient for high-resolution texture streaming. The 512 MB VRAM capacity is another constraint; this is a hard limit for texture storage, and modern games with high-resolution texture packs would exceed it, causing texture thrashing or reduced draw distances. For users willing to play older titles or esports games with low graphical demands, this GPU remains functional. For any modern AAA release, the lack of newer API support and limited VRAM would render it unsuitable. The 50th percentile ranking reinforces that this is a mid-pack performer, not a high-end solution even in its own time.

Ray Tracing and Feature Set

The fact pack lists no ray tracing cores or tensor cores, which is consistent with the TeraScale architecture’s design, predating such dedicated hardware by over a decade. Consequently, there is no hardware-accelerated ray tracing capability. Any ray-traced effects would need to be software-based, which is impractical given the 880.0 GFLOPS compute budget and the lack of API support for such features.

The API support is limited to DirectX 10.1 (10_1) and OpenGL 3.3. There is no Vulkan support listed. This means the GPU is locked out of modern graphics APIs, which are required for the latest game engines and their advanced rendering techniques, including mesh shaders and variable rate shading. The DirectX 10.1 support does offer some advantages over DirectX 10, such as improved shader model 4.1 features and better antialiasing modes, but it is a generation behind the DirectX 11 feature set that became standard shortly after this GPU’s release. The OpenGL 3.3 support is similarly dated, lacking the compute shaders and multi-threaded command submission of OpenGL 4.x. For any user expecting modern feature support, the data is clear: this is a legacy part confined to older software ecosystems.

How It Compares

The nearestRivals field is empty in the fact pack, meaning there is no direct comparative data available from the dataset. This absence of rival scores and deltaPct values prevents any quantitative comparison against specific competing GPUs from the same era, such as NVIDIA’s mobile offerings or AMD’s own previous generation parts.

The predecessor to this chip is listed as the M8x series, and the successor is Manhattan. Without benchmark scores, the generational improvement cannot be quantified. Qualitatively, the M9x generation, which includes this GPU, represents a significant architectural step forward from M8x, with a higher transistor count (956 million) and a larger die size (256 mm²), suggesting more compute resources. The transition to the Manhattan successor would have brought further architectural changes, but no performance deltas are provided.

In the absence of rival data, the only positioning available is the 50th percentile rank. This indicates that the GPU performs better than half of all GPUs ever recorded in the database, which is a surprisingly high rank given its age, but this is skewed by the inclusion of many low-end integrated and entry-level discrete GPUs in the database. Against its direct contemporaries, it would likely rank higher, but the missing data prevents a precise statement. The user should interpret the 50th percentile as a median score across all historical hardware, not a direct comparison to other 2009 mobile GPUs.

Memory Subsystem

The memory subsystem is built around 512 MB of GDDR3 memory operating on a 256-bit bus. The memory clock is 888 MHz, which yields an effective data rate of 1776 Mbps. The total memory bandwidth is 56.83 GB/s. This configuration was typical for high-end mobile GPUs of the era, balancing capacity and bandwidth for the target resolution of the time.

The 256-bit bus width is a critical advantage over lower-tier mobile GPUs that often used 128-bit interfaces. This wider bus allows the memory controller to address more data per clock cycle, directly enabling the 56.83 GB/s bandwidth figure. However, the 512 MB capacity is a limitation. In 2009, 512 MB was considered the sweet spot for high-end mobile gaming, but it becomes a bottleneck at higher resolutions where texture data exceeds this capacity. The bandwidth of 56.83 GB/s is sufficient for 1600x900 resolution with moderate texture settings, but at 1920x1080 with high-resolution textures, the GPU would likely experience stuttering as data is swapped in and out of the limited VRAM.

The use of GDDR3, as opposed to GDDR5, is a notable point. GDDR5 offered higher bandwidth per pin, but the fact pack indicates this chip uses GDDR3 at 1776 Mbps effective. This choice likely reflects the power and thermal constraints of a mobile MXM module, where GDDR5’s higher clock speeds would have increased power draw and heat generation. The 56.83 GB/s bandwidth is therefore a measured compromise, providing adequate throughput for the GPU’s 880.0 GFLOPS compute capacity without exceeding the thermal envelope of a laptop chassis. For users attempting to run modern games that require more than 512 MB of VRAM or higher bandwidth, this subsystem will be the primary limiting factor, causing reduced texture quality and frame rate drops in memory-intensive scenes.