AMD Radeon 550X vs NVIDIA GeForce GTX 675MX Comparison

The AMD Radeon 550X and the NVIDIA GeForce GTX 675MX represent two very different approaches to mobile graphics, separated by nearly seven years of silicon evolution. The data shows a clash between a modern, efficient 14nm design and a larger, older 28nm Kepler part with twice the memory bus. While the GTX 675MX emerges as the faster card in the single available head-to-head test, the Radeon 550X counters with newer architectural features and a dramatically lower power draw. This analysis dissects the benchmark scores, architectural philosophies, and specification sheets to determine which GPU suits which workload.

Head-to-Head Benchmarks

The only direct benchmark comparison available in the data is the Geekbench OpenCL test, and it delivers a clear, if one-sided, result. In this compute-oriented workload, the NVIDIA GeForce GTX 675MX scores 10,723 points, while the AMD Radeon 550X trails significantly with 8,866 points. This represents a -17.3% delta for the AMD card, meaning the GTX 675MX is approximately 21% faster in raw OpenCL performance. The margin is substantial, suggesting that the older NVIDIA chip’s higher shading unit count (960 vs 512) and wider 256-bit memory interface provide a decisive advantage in parallel compute tasks that scale with raw throughput.

However, context from the broader benchmark landscape is critical. The Radeon 550X counters with a stronger showing in the Geekbench Vulkan test, scoring 8,970 points — a figure that is actually higher than its OpenCL score. This indicates that the GCN 4.0 architecture responds well to modern, lower-level graphics APIs, potentially narrowing the gap in gaming scenarios that leverage Vulkan. Meanwhile, the GTX 675MX has a separate Geekbench Metal score of 6,131, which is far lower than its OpenCL result, suggesting that its Kepler architecture is less efficient under Apple’s Metal API. The Radeon 550X also holds a higher overall percentile rank at 45 versus the GTX 675MX’s 43, despite the latter’s higher average raw score in OpenCL. This discrepancy hints that the AMD card’s performance is more consistent across different types of workloads.

Looking at the nearest rivals provides another layer of interpretation. The Radeon 550X (average score 8,918) sits within a tight cluster: it is a mere 0.6% ahead of the AMD Radeon Pro WX 5100 and 0.8% ahead of the AMD Radeon R9 M265X, while trailing the NVIDIA GeForce GTX 660 by -1.2% and the NVIDIA TITAN V CEO Edition by -1.3%. This shows that the 550X punches near the weight class of desktop GTX 660, a notable achievement for a mobile chip. Conversely, the GTX 675MX (average score 8,427) is nearly tied with the AMD Radeon 880M (-0.1%) and NVIDIA GeForce MX330 (-0.4%), but leads the AMD Radeon R9 M375X by 1.2%. The data implies that the GTX 675MX, despite its age, holds its own against much newer entry-level parts, but it does not dominate them.

The Verdict

From the benchmark data alone, the NVIDIA GeForce GTX 675MX is the clear winner in raw compute performance. Its 17.3% lead over the Radeon 550X in Geekbench OpenCL is the only direct head-to-head metric available, and it is decisive. Users whose primary workload is OpenCL-accelerated compute — such as video encoding, physics simulation, or data processing — should favor the NVIDIA card. The GTX 675MX also offers a higher texture fill rate (52.32 GTexel/s vs 38.98 GTexel/s) and over twice the pixel throughput per clock, though its overall pixel rate (13.08 GPixel/s) is lower due to its much lower clock speeds.

However, the verdict is not universally in NVIDIA’s favor. The Radeon 550X shows superior Vulkan performance in its own benchmark suite, scoring 8,970 points, which suggests it may be the better choice for modern games that utilize Vulkan. Its newer architecture also supports newer API features — notably DirectX 12 (12_0) versus the GTX 675MX’s more limited DirectX 12 (11_0) profile. The AMD card is also dramatically more power-efficient, with a 50 W TDP versus the GTX 675MX’s 100 W. This is not a minor difference; it halves the thermal and power budget required, making the 550X far more suitable for thin-and-light laptops or systems with limited cooling.

The data ultimately points to a trade-off between raw compute power and architectural modernity. The GTX 675MX wins the compute crown, but the Radeon 550X offers better API support and efficiency. For a user who needs maximum OpenCL throughput regardless of power draw, the GTX 675MX is the answer. For a user who prioritizes modern gaming API compatibility and longer battery life, the Radeon 550X is the more sensible choice, even if it loses the single benchmark.

Where Each One Wins

The NVIDIA GeForce GTX 675MX wins decisively in OpenCL compute workloads. Its 10,723 score outpaces the Radeon 550X by 17.3%, making it the superior option for general-purpose GPU computing that relies on this API. This is reinforced by its hardware specs: 960 shading units, 80 texture mapping units, and 32 ROPs provide a massive parallel execution resource. The 115.2 GB/s memory bandwidth, while only marginally higher than the AMD card’s 112.0 GB/s, is delivered over a 256-bit bus, which can be more efficient for certain access patterns. The GTX 675MX’s higher average benchmark score (8,427 vs the 550X’s 8,918) is misleading because it is dragged down by its low Metal score; in OpenCL, it is clearly superior.

The AMD Radeon 550X wins in the Vulkan API arena, posting 8,970 points in Geekbench Vulkan — a score that is higher than its OpenCL result. This suggests that its GCN 4.0 architecture scales better with modern, low-overhead APIs. It also wins on efficiency: a 50 W TDP is exactly half of the GTX 675MX’s 100 W, and it requires only a 250 W suggested PSU while the NVIDIA card has no such specification. The Radeon 550X also supports Vulkan 1.3, a full version ahead of the GTX 675MX’s 1.2.175 support. For gamers playing Vulkan-based titles, the 550X’s newer driver and API stack may yield better frame pacing and lower latency, even if raw compute is lower.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon 550X has an average benchmark score of 8,918, which is higher than the NVIDIA GeForce GTX 675MX’s 8,427. However, this average is based on different test suites; the GTX 675MX only has OpenCL and Metal scores, while the 550X has OpenCL and Vulkan scores.

Q: How much faster is the NVIDIA GeForce GTX 675MX in OpenCL?

A: The GTX 675MX scores 10,723 in Geekbench OpenCL, while the Radeon 550X scores 8,866. This gives the NVIDIA card a 17.3% lead in that specific test.

Q: Does the AMD Radeon 550X support newer graphics APIs?

A: Yes. The Radeon 550X supports DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3. The GTX 675MX supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175, which is an older version of the Vulkan spec.

Q: What is the power consumption difference between the two cards?

A: The AMD Radeon 550X has a TDP of 50 W, while the NVIDIA GeForce GTX 675MX has a TDP of 100 W. The Radeon 550X also lists a suggested PSU of 250 W, whereas the GTX 675MX does not have a suggested PSU specification.

Q: Which GPU has a higher memory bandwidth?

A: The NVIDIA GeForce GTX 675MX has a slightly higher memory bandwidth of 115.2 GB/s compared to the AMD Radeon 550X’s 112.0 GB/s. The GTX 675MX achieves this with a 256-bit memory bus, while the 550X uses a 128-bit bus.

Q: Are both GPUs still in production?

A: No. Both the AMD Radeon 550X and the NVIDIA GeForce GTX 675MX are listed as end-of-life products in the data.

Architecture Differences

The two GPUs are built on fundamentally different architectures and process nodes. The AMD Radeon 550X uses the Lexa chip, based on the GCN 4.0 architecture, fabricated on a 14 nm process at GlobalFoundries. It contains 2,200 million transistors on a 103 mm² die, yielding a transistor density of 21.4M / mm². This modern, dense design allows for high clock speeds — a base of 1082 MHz and boost of 1218 MHz — which drives its pixel rate of 19.49 GPixel/s. The architecture natively supports fp16 compute at a 1:1 ratio with fp32, offering 1,247.2 GFLOPS for both precision types.

The NVIDIA GeForce GTX 675MX uses the GK104 chip, based on the much older Kepler architecture, fabricated on a 28 nm process at TSMC. This is a much larger chip: 3,540 million transistors on a 294 mm² die, with a transistor density of only 12.0M / mm². The larger, less dense design runs at lower clocks — the data lists no base or boost clock — which explains its lower pixel rate of 13.08 GPixel/s despite having 32 ROPs. Its fp32 throughput of 1,255.7 GFLOPS is nearly identical to the Radeon 550X, but it has no fp16 support listed. The GTX 675MX’s Kepler architecture is built for a different era, with a focus on raw shader throughput rather than modern API efficiency.

Specification Differences

The two cards differ across nearly every major specification field. The process node is a clear generational gap: 14 nm for AMD versus 28 nm for NVIDIA. The transistor count favors NVIDIA (3,540 million vs 2,200 million), as does the die size (294 mm² vs 103 mm²). The shading units are nearly double on the GTX 675MX (960 vs 512), as are the TMUs (80 vs 32) and ROPs (32 vs 16). The texture rate is higher on NVIDIA (52.32 GTexel/s vs 38.98 GTexel/s), but the pixel rate is higher on AMD (19.49 GPixel/s vs 13.08 GPixel/s).

The memory subsystem shows a split: both offer 2 GB of GDDR5, but the GTX 675MX uses a 256-bit bus with 115.2 GB/s bandwidth, while the Radeon 550X uses a 128-bit bus with 112.0 GB/s. The TDP is drastically different: 50 W for AMD versus 100 W for NVIDIA. The bus interface also differs: PCIe 3.0 x8 for the Radeon 550X versus MXM-B (3.0) for the GTX 675MX, reflecting its mobile module format. The display outputs are fixed on the AMD card (1x DVI, 1x HDMI 2.0b, 1x DisplayPort 1.4a), while the NVIDIA card is listed as "Portable Device Dependent." The API support differs in DirectX (12_0 vs 11_0) and Vulkan (1.3 vs 1.2.175). Finally, the release dates are separated by over six years: the GTX 675MX launched on 2012-09-30, while the Radeon 550X launched on 2019-03-26.