AMD Radeon R5 M255 vs AMD Radeon R5 M320 Comparison

# AMD Radeon R5 M255 vs AMD Radeon R5 M320

Two budget-oriented mobile GPUs from AMD's Gem System family, the R5 M255 and R5 M320, target entry-level laptops but take different paths. The M255 uses the Topaz chip with GCN 3.0 architecture, while the M320 relies on the older Jet chip with GCN 1.0. Both are end-of-life products, but benchmark data shows they trade blows depending on the workload. The M255 edges ahead in average score at 4788 versus 4657, but the M320 counters with a higher OpenCL result. Here's how they stack up.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon R5 M255 leads with an average benchmark score of 4788, while the R5 M320 trails at 4657. That is a difference of approximately 2.8% in the M255's favor.

Q: How do the two compare in Geekbench OpenCL performance?

A: The R5 M320 wins in Geekbench OpenCL with a score of 5051, beating the M255's 4650 by 7.9%. This is the M320's strongest showing.

Q: Which GPU performs better in Geekbench Vulkan?

A: The R5 M255 takes the Vulkan test decisively, scoring 4925 against the M320's 4262. That is a 15.6% advantage for the M255, making it the clear pick for Vulkan-based workloads.

Q: What are the memory configurations of these two GPUs?

A: The R5 M255 has 2 GB of DDR3 memory on a 128-bit bus, delivering 32.00 GB/s bandwidth. The R5 M320 has 4 GB of DDR3 on a narrower 64-bit bus, resulting in only 16.00 GB/s bandwidth.

Q: Which GPU has more shading units and texture units?

A: The R5 M255 has 384 shading units and 24 texture mapping units (TMUs). The R5 M320 has 320 shading units and 20 TMUs. Both have 8 raster operation units (ROPs).

Q: What are the percentile rankings of these GPUs among all GPUs?

A: The R5 M255 sits at the 28th percentile, while the R5 M320 sits just below at the 27th percentile. Both are firmly in the entry-level segment.

Architecture Differences

The architectural gap between these two GPUs is significant, even though both are built on TSMC's 28 nm process. The R5 M255 uses the Topaz chip with GCN 3.0 architecture, while the R5 M320 uses the Jet chip with the older GCN 1.0 architecture. This generational difference explains several performance characteristics.

Transistor counts tell a stark story. The Topaz chip packs 1,550 million transistors on a 125 mm² die, while the Jet chip has just 690 million transistors on a 56 mm² die. That is more than double the transistor count for the M255, with a transistor density of 12.4M per mm² versus 12.3M per mm² for the M320. The M255's larger, more complex chip enables higher compute throughput.

Clock speeds also differ. The M255 runs at a base clock of 925 MHz with a boost up to 940 MHz. The M320 is slower, with a base of 780 MHz and a boost of 855 MHz. Combined with the extra shading units, the M255 achieves 721.9 GFLOPS of FP32 performance, while the M320 manages 547.2 GFLOPS. The M255 also supports FP16 at a 1:1 ratio (721.9 GFLOPS), whereas the M320 has no listed FP16 capability.

Memory architecture diverges as well. The M255 has a 128-bit memory bus with 2 GB of DDR3, providing 32.00 GB/s of bandwidth. The M320 has a 64-bit bus with 4 GB of DDR3, but only 16.00 GB/s of bandwidth. The M255's wider bus doubles memory bandwidth, which matters for texture-heavy workloads.

API support is another differentiator. The M255 supports DirectX 12 (12_0), while the M320 only reaches DirectX 12 (11_1). Both share OpenGL 4.6 and Vulkan 1.2.170 support. The M255's newer architecture also enables better feature support in modern graphics APIs.

Head-to-Head Benchmarks

The two GPUs split their head-to-head benchmark results, with each winning one of the two tests. The M320 takes the Geekbench OpenCL test with a score of 5051, beating the M255's 4650 by 7.9%. This is a notable win for the older architecture, suggesting that OpenCL workloads favor the M320's specific configuration.

The M255 responds in the Geekbench Vulkan test, scoring 4925 against the M320's 4262. This 15.6% margin is the largest performance gap in either direction. Vulkan is a modern low-overhead API, and the GCN 3.0 architecture of the M255 appears to handle it significantly better than the GCN 1.0 silicon in the M320.

Looking at the broader context, the M255's average benchmark score of 4788 places it near the NVIDIA GeForce RTX 3080 12 GB, which scores 4791 with a delta of -0.1%. It also sits close to the AMD Radeon R5 M335 (4752, 0.8% delta) and the NVIDIA GeForce 940MX (4844, -1.2% delta). The M320's average of 4657 matches the AMD Radeon RX 9060 XT 16 GB exactly (0% delta), and it is within 0.6% of the NVIDIA Quadro P400 (4684) and within 0.8% of the NVIDIA GeForce GTX 970M (4628) and NVIDIA Quadro M3000M (4621).

These rival comparisons show that both GPUs occupy a narrow performance band. The M255's 28th percentile ranking and the M320's 27th percentile ranking confirm they are entry-level parts, but the M255 has a slight overall edge.

Specification Differences

The key specification differences between the R5 M255 and R5 M320 are substantial. Starting with the chip and architecture, the M255 uses Topaz with GCN 3.0, while the M320 uses Jet with GCN 1.0. Transistor counts are 1,550 million versus 690 million, and die sizes are 125 mm² versus 56 mm².

Clock speeds favor the M255 across the board. Its base clock is 925 MHz versus 780 MHz, and its boost clock is 940 MHz versus 855 MHz. Both have the same memory clock of 1000 MHz (2 Gbps effective), but the memory buses differ: 128-bit for the M255 and 64-bit for the M320. This results in bandwidth of 32.00 GB/s versus 16.00 GB/s.

Memory capacity goes the other way. The M255 has 2 GB of DDR3, while the M320 has 4 GB. The M320's larger capacity may help with certain applications, but the halved bandwidth is a significant drawback.

Compute resources differ as well. The M255 has 384 shading units, 24 TMUs, and 8 ROPs. The M320 has 320 shading units, 20 TMUs, and 8 ROPs. Pixel rates are 7.520 GPixel/s for the M255 and 6.840 GPixel/s for the M320. Texture rates are 22.56 GTexel/s versus 17.10 GTexel/s. FP32 performance is 721.9 GFLOPS versus 547.2 GFLOPS.

The M255 has no listed slot width, while the M320 is listed as "IGP" (integrated graphics processor). The M320's display outputs are described as "Portable Device Dependent," while the M255 has no listed display outputs. Both use a PCIe 3.0 x8 bus interface and are end-of-life products. The M255 was released on 2014-10-11, and the M320 on 2015-05-04. Both list Solar System as predecessor and Polaris Mobile as successor.

Where Each One Wins

The R5 M255 wins in scenarios that benefit from its newer architecture and higher raw compute throughput. Its GCN 3.0 design and 721.9 GFLOPS FP32 performance make it better suited for modern graphics APIs, as demonstrated by the 15.6% Vulkan victory. The wider 128-bit memory bus and 32.00 GB/s bandwidth also give it an advantage in texture-heavy scenes and higher-resolution workloads. If you are running Vulkan-based games or applications, the M255 is the clear choice.

The R5 M320 wins in OpenCL workloads, as shown by its 5051 score versus 4650. This 7.9% advantage suggests that certain compute tasks, particularly those optimized for OpenCL, run better on the M320 despite its older architecture. The 4 GB memory capacity is also a point in its favor, potentially allowing larger datasets to reside in GPU memory compared to the M255's 2 GB. For productivity apps that rely on OpenCL and benefit from more memory, the M320 has a case.

For general everyday use, the M255's higher average benchmark score of 4788 versus 4657 gives it a slight overall edge. Its 28th percentile ranking versus 27th also reflects marginally better standing among all GPUs.

The Verdict

Choose the AMD Radeon R5 M255 if you prioritize modern API support and raw compute performance. Its GCN 3.0 architecture, 384 shading units, and 128-bit memory bus deliver better Vulkan performance by 15.6% and higher average benchmark scores overall (4788 versus 4657). The 721.9 GFLOPS FP32 throughput and 32.00 GB/s bandwidth make it the more capable part for contemporary workloads. It also closely matches the NVIDIA GeForce RTX 3080 12 GB in average score, which is remarkable given the massive difference in GPU class.

Choose the AMD Radeon R5 M320 if OpenCL performance and memory capacity are your priorities. Its 5051 OpenCL score beats the M255 by 7.9%, and the 4 GB frame buffer doubles the M255's 2 GB. This could matter for specific compute tasks or applications that exceed 2 GB of GPU memory usage. However, the 64-bit memory bus and 16.00 GB/s bandwidth are severe limitations, and the older GCN 1.0 architecture shows its age in Vulkan performance.

For most users, the M255 is the better overall GPU. The data shows a clear split, but the M255's wins come in the more future-facing API (Vulkan) and its average score is higher. The M320's OpenCL advantage is real but narrower, and its memory bandwidth deficit is hard to overcome. Neither GPU is a strong performer today, but if you must pick one, the M255 offers better architecture, faster clocks, and more balanced performance.