AMD Radeon R5 M255 vs AMD Radeon R6 M255DX Comparison

AMD Radeon R6 M255DX and AMD Radeon R5 M255 are both end-of-life mobile graphics solutions from AMD’s Gem System generation, but they target different segments of the laptop market. The R6 M255DX is an integrated graphics processor (IGP) built into the chipset, sharing system memory, while the R5 M255 is a discrete part with its own dedicated VRAM. Benchmark data shows the R5 M255 edges out the R6 M255DX in the single shared test, but the two cards have distinct architectural foundations and performance characteristics that make them suitable for different use cases. The following analysis breaks down where each wins, how they differ internally, and what the numbers actually mean for a buyer.

Where Each One Wins

The data shows a clear, if narrow, victory for the AMD Radeon R5 M255 in the only head-to-head benchmark available. In Geekbench Vulkan, the R5 M255 scores 4925 against the R6 M255DX’s 4867, a delta of -1.2% from the R6’s perspective. That makes the R5 M255 the winner in raw compute performance under the Vulkan API, which is the only test where both cards were measured. The R6 M255DX, however, is not without its own merits. As an IGP with "System Shared" memory, it wins on integration simplicity—there is no separate VRAM to manage, and its performance is "System Dependent," meaning it can scale with faster system memory in a laptop. The R5 M255, by contrast, has fixed 2 GB of DDR3 on a 128-bit bus, so its 32.00 GB/s bandwidth is consistent regardless of the host system.

In terms of placement among rivals, the R6 M255DX sits at the 28th percentile of all GPUs, with an average benchmark score of 4867. Its nearest rival is the NVIDIA GeForce GTS 450 at 4893 (0.5% ahead), and it is effectively tied with the GeForce GTX 560M (4855, 0.2% behind) and the GeForce 940MX (4844, 0.5% behind). The R5 M255 also sits at the 28th percentile, with an average score of 4788, but its nearest rivals tell a different story: it is 0.1% behind the GeForce RTX 3080 12 GB (4791), 0.8% ahead of the AMD Radeon R5 M335 (4752), and 1.3% ahead of the AMD Radeon R8 M445DX (4727). The R5 M255’s average is dragged down by its OpenCL score of 4650, but its Vulkan result is actually higher than the R6’s. For practical use, the R5 M255 wins on raw speed, while the R6 M255DX wins on being a zero-cost, zero-space integrated solution.

Architecture Differences

The two GPUs are built on fundamentally different architectures despite sharing the same 28 nm TSMC process node. The R6 M255DX uses the Jet chip with GCN 1.0 architecture, while the R5 M255 uses the Topaz chip with GCN 3.0. This generational leap matters: GCN 3.0 introduces architectural refinements that improve instruction efficiency and feature support. The R6 M255DX is part of the "Gem System Hybrid (Rx M200)" generation, whereas the R5 M255 is from the "Gem System (R5 M200)" generation, released about nine months later. The R5 M255’s predecessor is listed as "Solar System," and its successor is "Polaris Mobile," giving it a clearer lineage in AMD’s mobile roadmap.

Transistor counts and die sizes differ substantially. The R6 M255DX packs 690 million transistors on a 56 mm² die, yielding a density of 12.3M transistors per mm². The R5 M255 more than doubles that with 1,550 million transistors on a 125 mm² die, at a nearly identical density of 12.4M per mm². This means the R5 M255 has more than twice the silicon area dedicated to compute resources. The R6 M255DX is an IGP with a "Portable Device Dependent" display output, while the R5 M255 connects via PCIe 3.0 x8, making it a discrete card that can be paired with a variety of CPUs.

Memory architecture is the other major split. The R6 M255DX uses "System Shared" memory with a "System Shared" bus width and "System Dependent" bandwidth—it borrows from the host’s RAM, so performance varies with the laptop’s memory configuration. The R5 M255 has dedicated 2 GB of DDR3 running at 1000 MHz (2 Gbps effective) on a 128-bit bus, delivering a fixed 32.00 GB/s. This makes the R5 M255 more predictable in performance and less reliant on the rest of the system.

Head-to-Head Benchmarks

The only direct benchmark comparison is Geekbench Vulkan, where the R5 M255 wins with a score of 4925 versus the R6 M255DX’s 4867. That is a 1.2% difference from the R6’s perspective, which is close enough to be within run-to-run variance, but the R5 M255 is consistently ahead in this metric. The R6 M255DX’s nearest rival data shows it is 0.7% behind the GeForce RTX 5060 Ti 8 GB (4901), which is a much newer and more powerful card—this suggests the R6’s Vulkan score is solid for its age. The R5 M255, meanwhile, is 0.1% behind the RTX 3080 12 GB (4791) in average score, which reflects how well it scales in certain workloads, though its average is pulled down by the OpenCL result.

In raw throughput, the R5 M255 has clear advantages. Its FP32 compute is 721.9 GFLOPS versus the R6 M255DX’s 547.2 GFLOPS, a 31.9% advantage. The R5 M255 also has higher pixel and texture rates: 7.520 GPixel/s versus 6.840 GPixel/s, and 22.56 GTexel/s versus 17.10 GTexel/s. These numbers translate to faster fill rates and better texture-heavy workload performance. The R5 M255 also supports FP16 at 721.9 GFLOPS (1:1), while the R6 M255DX has no FP16 support listed. For modern games and compute tasks that leverage FP16, the R5 M255 has a definitive edge.

The R5 M255’s higher clock speeds—925 MHz base and 940 MHz boost versus the R6 M255DX’s 780 MHz base and 855 MHz boost—further cement its lead. The R5 M255 also has more shading units (384 versus 320) and more TMUs (24 versus 20), though both have 8 ROPs. These differences add up to a card that is measurably faster in every throughput metric, even if the Vulkan score difference is small.

Specification Differences

The two cards differ in nearly every measurable specification except for process node, foundry, and ROP count. Here are the key differences:

• Chip and Architecture: R6 M255DX uses Jet (GCN 1.0), R5 M255 uses Topaz (GCN 3.0)
• Transistors: 690 million versus 1,550 million
• Die Size: 56 mm² versus 125 mm²
• Transistor Density: 12.3M / mm² versus 12.4M / mm² (negligible)
• Base Clock: 780 MHz versus 925 MHz
• Boost Clock: 855 MHz versus 940 MHz
• Memory Size: System Shared versus 2 GB
• Memory Type: System Shared versus DDR3
• Memory Bus Width: System Shared versus 128 bit
• Memory Bandwidth: System Dependent versus 32.00 GB/s
• Memory Clock: System Shared versus 1000 MHz (2 Gbps effective)
• Shading Units: 320 versus 384
• TMUs: 20 versus 24
• Pixel Rate: 6.840 GPixel/s versus 7.520 GPixel/s
• Texture Rate: 17.10 GTexel/s versus 22.56 GTexel/s
• FP32: 547.2 GFLOPS versus 721.9 GFLOPS
• FP16: null versus 721.9 GFLOPS (1:1)
• Bus Interface: IGP versus PCIe 3.0 x8
• Display Outputs: Portable Device Dependent versus null (not specified)
• DirectX Support: 12 (11_1) versus 12 (12_0)
• Release Date: 2014-01-06 versus 2014-10-11
• Predecessor: null versus Solar System
• Successor: null versus Polaris Mobile

The DirectX difference is notable: the R5 M255 supports DirectX 12 (12_0), while the R6 M255DX only supports DirectX 12 (11_1). This means the R5 M255 is better positioned for titles that use newer DirectX 12 features. Both support OpenGL 4.6 and Vulkan 1.2.170.

FAQ

Q: Which GPU is faster in Vulkan benchmarks?

A: The AMD Radeon R5 M255 scores 4925 in Geekbench Vulkan, beating the R6 M255DX’s 4867 by 1.2%. This is the only head-to-head benchmark available, and the R5 M255 wins it.

Q: Do these GPUs support the same APIs?

A: Both support OpenGL 4.6 and Vulkan 1.2.170, but they differ in DirectX. The R5 M255 supports DirectX 12 (12_0), while the R6 M255DX is limited to DirectX 12 (11_1). This gives the R5 M255 better compatibility with newer DirectX 12 titles.

Q: How does the R6 M255DX compare to the NVIDIA GeForce 940MX?

A: The R6 M255DX scores 4867 on average, which is 0.5% ahead of the GeForce 940MX’s 4844. The R5 M255, by comparison, is 1.2% behind the 940MX with its 4788 average, though its Vulkan score of 4925 is higher than the 940MX’s average.

Q: Which GPU has more memory bandwidth?

A: The R5 M255 has a fixed 32.00 GB/s from its 2 GB DDR3 on a 128-bit bus. The R6 M255DX uses system-shared memory with "System Dependent" bandwidth, so its performance varies with the laptop’s RAM configuration and is not a fixed number.

Q: Is the R5 M255 a discrete GPU?

A: Yes. The R5 M255 uses a PCIe 3.0 x8 bus interface and has dedicated 2 GB VRAM, making it a discrete card. The R6 M255DX is an IGP with no dedicated memory, using the system’s RAM instead.

Q: Which GPU has higher compute throughput?

A: The R5 M255 delivers 721.9 GFLOPS FP32, which is 31.9% higher than the R6 M255DX’s 547.2 GFLOPS. The R5 M255 also supports FP16 at 721.9 GFLOPS, while the R6 M255DX has no FP16 capability listed.

The Verdict

The data points to a clear choice for most users: the AMD Radeon R5 M255 is the stronger performer. It wins the only head-to-head benchmark, has 31.9% higher FP32 compute, 31.9% higher texture rate, and 9.9% higher pixel rate compared to the R6 M255DX. It also has more shading units (384 versus 320), more TMUs (24 versus 20), and a newer architecture (GCN 3.0 versus GCN 1.0). The R5 M255’s dedicated 2 GB VRAM with a fixed 32.00 GB/s bandwidth removes the variable of system memory performance, making it the more reliable choice for gaming and compute tasks. Its DirectX 12 (12_0) support is also a meaningful advantage for modern software.

The R6 M255DX is not without a niche, however. As an IGP with system-shared memory, it requires no separate video memory and has no discrete card footprint. It is a zero-cost addition to a laptop’s chipset, and its Vulkan score of 4867 is competitive—it is only 0.7% behind the GeForce RTX 5060 Ti 8 GB and 0.5% ahead of the GeForce 940MX. For a buyer who cannot or will not pay for a discrete GPU, the R6 M255DX offers surprisingly capable integrated graphics.

But for anyone choosing between these two specific parts, the R5 M255 is the better buy based on the benchmarks. Its average score of 4788 is slightly lower than the R6’s 4867, but that is only because the R5 M255’s OpenCL score of 4650 drags it down. In the Vulkan test that matters most for modern gaming, the R5 M255 wins outright. The R5 M255 also has a clearer upgrade path, with a successor listed as Polaris Mobile, while the R6 M255DX has no successor. If performance is the priority, take the R5 M255. If integration and simplicity are paramount, the R6 M255DX is a capable fallback.