AMD Radeon R5 M320 vs AMD Radeon R6 M255DX Comparison

The AMD Radeon R6 M255DX and AMD Radeon R5 M320 are both entry-level mobile graphics solutions built on the same underlying silicon, yet benchmark data reveals a clear performance hierarchy between them. The R6 M255DX holds a distinct lead in the only directly comparable test, while the R5 M320 counters with a broader benchmark portfolio and a slightly higher average score across its tested workloads. This analysis examines where each part wins, what separates their architectures, and which GPU the data suggests for specific use cases.

Where Each One Wins

The benchmark results present a nuanced picture of where each GPU excels. The AMD Radeon R6 M255DX wins the only head-to-head comparison available, the geekbench_vulkan test, with a score of 4867 against the R5 M320’s 4262. That is a 14.2% advantage, a substantial margin in a synthetic workload that stresses modern graphics API overhead and compute. For users running Vulkan-based applications, the R6 M255DX is the clear choice based on this data.

The AMD Radeon R5 M320, however, demonstrates a different kind of strength. It has two benchmark entries in its profile: a geekbench_opencl score of 5051 and a geekbench_vulkan score of 4262. Its average benchmark score across those tests is 4657, which is slightly higher than the R6 M255DX’s 4867 on a single Vulkan run. This suggests the R5 M320 may be more balanced across different compute APIs, particularly OpenCL, where its score exceeds the R6 M255DX’s Vulkan result by 184 points. For workloads that rely on OpenCL—common in certain productivity and scientific applications—the R5 M320 appears better suited, even though no direct head-to-head OpenCL test exists in the data.

Architecture Differences

Both GPUs share the same fundamental architecture, which explains their similar specifications. They are built on the Jet chip with GCN 1.0 architecture, fabricated on a 28 nm process at TSMC. Both feature 690 million transistors on a 56 mm² die, yielding a transistor density of 12.3M per mm². The core configuration is identical: 320 shading units, 20 texture mapping units, and 8 raster operation units. Clock speeds match exactly at 780 MHz base and 855 MHz boost, producing the same pixel rate of 6.840 GPixel/s, texture rate of 17.10 GTexel/s, and FP32 throughput of 547.2 GFLOPS.

The key architectural divergence lies in memory. The R6 M255DX uses System Shared memory, meaning it relies on the host system’s RAM with a bus width, size, and bandwidth that are all system-dependent. The R5 M320, by contrast, has dedicated memory: 4 GB of DDR3 on a 64-bit bus, delivering 16.00 GB/s of bandwidth. The R5 M320’s memory clock is listed as 1000 MHz with 2 Gbps effective transfer rate. This dedicated memory arrangement gives the R5 M320 a potential advantage in scenarios where consistent memory latency and bandwidth are critical, though the system-dependent nature of the R6 M255DX’s memory could theoretically allow it to access faster system RAM in some configurations.

Another difference is the bus interface. The R6 M255DX is listed as IGP, meaning it is integrated directly into the system. The R5 M320 uses PCIe 3.0 x8, which allows it to communicate with the host processor over a dedicated expansion bus. The R5 M320 also has defined generation lineage: its predecessor is “Solar System” and its successor is “Polaris Mobile,” while the R6 M255DX’s generation is listed as “Gem System Hybrid (Rx M200)” with no predecessor or successor named.

FAQ

Q: Which GPU has a higher Vulkan benchmark score?

A: The AMD Radeon R6 M255DX scores 4867 on geekbench_vulkan, while the AMD Radeon R5 M320 scores 4262 on the same test. This gives the R6 M255DX a 14.2% advantage in this specific benchmark.

Q: Does the R5 M320 have any benchmark where it outperforms the R6 M255DX?

A: Yes, the R5 M320 has a geekbench_opencl score of 5051, which is higher than the R6 M255DX’s single geekbench_vulkan score of 4867. However, no direct head-to-head OpenCL comparison is available in the data.

Q: Are these two GPUs based on the same chip?

A: Yes, both the AMD Radeon R6 M255DX and AMD Radeon R5 M320 use the Jet chip with GCN 1.0 architecture, fabricated on a 28 nm process at TSMC with 690 million transistors.

Q: What is the memory configuration difference between the two?

A: The R6 M255DX uses System Shared memory with system-dependent bandwidth, while the R5 M320 has 4 GB of dedicated DDR3 memory on a 64-bit bus with 16.00 GB/s bandwidth.

Q: Which GPU has a higher average benchmark score?

A: The R5 M320 has an average benchmark score of 4657 across its two tests, while the R6 M255DX has an average score of 4867 based on its single benchmark. The R6 M255DX’s average is higher.

Q: What is the production status of these GPUs?

A: Both the AMD Radeon R6 M255DX and AMD Radeon R5 M320 are listed as end-of-life products.

Specification Differences

The primary specification differences between the AMD Radeon R6 M255DX and AMD Radeon R5 M320 are concentrated in memory and connectivity. The R6 M255DX relies on System Shared memory for size, type, bus width, and bandwidth, with bandwidth listed as “System Dependent.” The R5 M320 has 4 GB of DDR3 memory on a 64-bit bus with a fixed 16.00 GB/s bandwidth and a memory clock of 1000 MHz with 2 Gbps effective transfer rate. The R6 M255DX has no separate memory clock specification because it uses system memory.

The bus interface also differs: the R6 M255DX is IGP, while the R5 M320 uses PCIe 3.0 x8. Both GPUs share the same core specifications—shading units, TMUs, ROPs, clock speeds, pixel rate, texture rate, and FP32 performance are identical. They also have the same API support: DirectX 12 (11_1), OpenGL 4.6, and Vulkan 1.2.170. Both have a TDP listed as null, a slot width of IGP, no power connectors, no suggested PSU, and display outputs listed as “Portable Device Dependent.” Their release dates differ, with the R6 M255DX launching on 2014-01-06 and the R5 M320 launching on 2015-05-04.

Head-to-Head Benchmarks

The single head-to-head benchmark in the data is geekbench_vulkan, and the AMD Radeon R6 M255DX dominates it. The R6 M255DX scores 4867, while the R5 M320 scores 4262, yielding a delta of 14.2% in favor of the R6 M255DX. This is a significant margin in a Vulkan compute workload, suggesting the R6 M255DX has better raw API-level performance despite identical core architecture and clock speeds. The difference likely stems from how each GPU handles memory access patterns in Vulkan, with the R6 M255DX’s system-shared memory potentially allowing faster data exchange in certain workloads.

The R5 M320’s strongest showing comes from its geekbench_opencl result of 5051, which is not directly comparable to the R6 M255DX but exceeds the R6 M255DX’s Vulkan score by 184 points. If the R5 M320’s OpenCL advantage is consistent, it could outperform the R6 M255DX in OpenCL-specific applications, even though the available head-to-head data does not capture this. The R5 M320’s average benchmark score of 4657 is lower than the R6 M255DX’s 4867, but this average includes the lower Vulkan result, pulling it down.

Looking at nearest rivals provides additional context. The R6 M255DX’s Vulkan score of 4867 places it 0.2% ahead of the NVIDIA GeForce GTX 560M (4855) and 0.5% ahead of the NVIDIA GeForce 940MX (4844), while trailing the NVIDIA GeForce GTS 450 (4893) by 0.5% and the NVIDIA GeForce RTX 5060 Ti 8 GB (4901) by 0.7%. The R5 M320’s average score of 4657 is exactly equal to the AMD Radeon RX 9060 XT 16 GB (4657), 0.6% behind the NVIDIA Quadro P400 (4684), but 0.6% ahead of the NVIDIA GeForce GTX 970M (4628) and 0.8% ahead of the NVIDIA Quadro M3000M (4621). These comparisons show both GPUs hovering in a similar performance tier, with the R6 M255DX having a slight edge in the Vulkan metric.

The Verdict

The data points to a clear split in recommendations. The AMD Radeon R6 M255DX is the better choice for users prioritizing Vulkan-based workloads, where it holds a 14.2% advantage over the R5 M320 in the geekbench_vulkan test. Its higher single-benchmark score of 4867 also gives it a higher average benchmark score (4867) compared to the R5 M320’s 4657. For gaming or applications that leverage Vulkan, the R6 M255DX is the stronger performer.

The AMD Radeon R5 M320, however, makes a compelling case for users who need broader API support or prefer dedicated memory. Its geekbench_opencl score of 5051 is the highest single test result between the two GPUs, suggesting strong OpenCL performance that the R6 M255DX cannot match based on available data. The dedicated 4 GB DDR3 memory on a 64-bit bus with 16.00 GB/s bandwidth provides a fixed, predictable memory environment, unlike the system-dependent memory of the R6 M255DX. For productivity applications that rely on OpenCL or for users who want consistent memory performance without dependence on system RAM, the R5 M320 is the more sensible pick.

Both GPUs are end-of-life products with identical core architecture and clock speeds, so the decision hinges entirely on memory configuration and API-specific performance. The R6 M255DX wins the only direct comparison, but the R5 M320’s OpenCL strength and dedicated memory make it a valid alternative for different workloads. The data does not show one GPU as universally superior; instead, it reveals two parts optimized for different use cases within the same silicon family.