AMD Radeon Vega 8 Mobile vs NVIDIA GeForce GTX 675MX Comparison

NVIDIA GeForce GTX 675MX and AMD Radeon Vega 8 Mobile represent two very different approaches to mobile graphics. The GTX 675MX is a dedicated MXM module from the Kepler era, while the Vega 8 is an integrated GPU inside a Raven Ridge APU. The benchmark data shows a clear winner in raw compute, but the story becomes more nuanced when considering the architectural and specification differences that define their respective use cases.

Head-to-Head Benchmarks

The only shared benchmark in the database is Geekbench OpenCL, and here the NVIDIA GeForce GTX 675MX takes a decisive victory. The GTX 675MX scores 10,723 points, while the AMD Radeon Vega 8 Mobile manages 7,435 points. That works out to a 44.2% advantage for the NVIDIA part. This is not a small gap; it represents a substantial lead in general-purpose compute workloads as measured by OpenCL.

Looking at the average benchmark scores across all recorded tests, the GTX 675MX sits at 8,427 points, which places it in the 43rd percentile of all GPUs in the database. The Vega 8 Mobile, by contrast, has an average score of 7,203 points and sits in the 39th percentile. While the head-to-head OpenCL test shows a 44.2% delta, the average score difference is roughly 17% in favor of the GTX 675MX. This suggests that the OpenCL test is particularly favorable to the NVIDIA architecture, but even on average, the dedicated part remains ahead.

The nearest rival data reinforces the positioning of each card. The GTX 675MX’s closest competitor is the AMD Radeon 880M, which averages 8,436 points, a negligible 0.1% difference. The NVIDIA GeForce MX330 is also close at 8,458 points, just 0.4% ahead. On the other side, the Vega 8 Mobile’s nearest rival is the NVIDIA GeForce GTX 750 at 7,222 points, which is 0.3% faster. The GTX 970 also appears in the rival list with 7,157 points, a 0.6% deficit to the Vega 8, which is surprising given the GTX 970’s reputation, but the data is what it is.

For the single head-to-head benchmark, the GTX 675MX wins 1 out of 1 tests. There is no benchmark in the database where the Vega 8 Mobile comes out ahead.

Where Each One Wins

The GTX 675MX wins in raw OpenCL compute performance by a wide margin. If the workload is heavily parallel and can leverage the GPU’s shading units, the NVIDIA part is clearly the stronger choice. Its 44.2% lead in the OpenCL test is the single biggest differentiator in the data. Any application that scales well with compute throughput will favor the GTX 675MX.

The Vega 8 Mobile does not win any benchmark in the database, but its strengths lie elsewhere. Its architecture is more modern, and it supports newer API features, which we will cover in the architecture section. The data shows that the Vega 8 is not competitive in raw compute, but the database does not include gaming benchmarks or power efficiency tests. Given its 25 W TDP versus the GTX 675MX’s 100 W TDP, the Vega 8 is clearly designed for a different class of machine. The GTX 675MX requires an MXM module and a dedicated power budget, while the Vega 8 is an IGP that shares system memory and fits into slim laptops.

In practical terms, the GTX 675MX is the choice for compute-heavy tasks on a laptop that can accommodate a dedicated GPU. The Vega 8 Mobile is the choice for a lightweight, low-power system where the GPU is an afterthought and the CPU’s integrated graphics are sufficient for light duties.

Architecture Differences

The architectural gap between these two is significant. The GTX 675MX uses the GK104 chip based on NVIDIA’s Kepler architecture, built on a 28 nm process at TSMC. The chip contains 3,540 million transistors on a 294 mm² die, giving it a transistor density of 12.0 million transistors per mm². The Vega 8 Mobile uses the Raven-M chip based on AMD’s GCN 5.0 architecture, built on a 14 nm process at GlobalFoundries. That chip has 4,940 million transistors on a 210 mm² die, for a density of 23.5 million transistors per mm².

The process node difference is notable: 28 nm versus 14 nm. The newer process allows AMD to pack more transistors into a smaller die, and the density figures reflect that. However, the GTX 675MX has a much larger die overall, which gives it room for more specialized hardware.

The GTX 675MX has 960 shading units, 80 texture mapping units, and 32 raster output units. The Vega 8 Mobile has 512 shading units, 32 TMUs, and only 8 ROPs. That is a massive difference in ROP count, which directly impacts pixel fill rate. The GTX 675MX achieves 13.08 GPixel/s, while the Vega 8 Mobile manages only 8.808 GPixel/s. Texture rate follows the same trend: 52.32 GTexel/s for NVIDIA versus 35.23 GTexel/s for AMD.

FP32 performance is closer than the shading unit count might suggest. The GTX 675MX delivers 1,255.7 GFLOPS, while the Vega 8 Mobile delivers 1,127.4 GFLOPS. The NVIDIA part still wins, but only by about 11%. The Vega 8 does have a notable feature the GTX 675MX lacks: FP16 support at 2.255 TFLOPS (2:1). The GTX 675MX has no listed FP16 capability.

The memory architecture is fundamentally different. The GTX 675MX has 2 GB of dedicated GDDR5 memory on a 256-bit bus, yielding 115.2 GB/s of bandwidth. The Vega 8 Mobile uses system shared memory, with the bus width and bandwidth listed as system dependent. This is a critical disadvantage for the Vega 8 in memory-bandwidth-sensitive workloads, as it must contend with the CPU for memory access.

Specification Differences

The two GPUs differ on nearly every specification that matters. The process node is 28 nm for NVIDIA and 14 nm for AMD. Transistor count is 3,540 million versus 4,940 million. Die size is 294 mm² versus 210 mm². Transistor density is 12.0 million per mm² versus 23.5 million per mm².

The memory configuration is a stark contrast: 2 GB GDDR5 with a 256-bit bus and 115.2 GB/s bandwidth versus system shared memory with system dependent bandwidth. The GTX 675MX has 960 shading units, 80 TMUs, and 32 ROPs. The Vega 8 has 512 shading units, 32 TMUs, and 8 ROPs.

Clock speeds differ in structure as well. The GTX 675MX has no listed base or boost clock, only a memory clock of 900 MHz (3.6 Gbps effective). The Vega 8 has a base clock of 300 MHz and a boost clock of 1101 MHz. The Vega 8 also has game clock listed as null, while the GTX 675MX has no base or boost at all.

TDP is a major divider: 100 W for the GTX 675MX versus 25 W for the Vega 8. The slot width is MXM Module for NVIDIA and IGP for AMD. The bus interface is MXM-B (3.0) for NVIDIA and simply IGP for AMD. The API support also differs: the GTX 675MX supports DirectX 12 (11_0) and Vulkan 1.2.175, while the Vega 8 supports DirectX 12 (12_1) and Vulkan 1.3. Both support OpenGL 4.6.

The production status is end-of-life for both. The release dates are far apart: the GTX 675MX launched on 2012-09-30, while the Vega 8 launched on 2019-01-07. The GTX 675MX has a predecessor of GeForce 500M and successor of GeForce 700M. The Vega 8 has a predecessor of GCN 3.0 IGP and successor of Navi II IGP.

FAQ

Q: Which GPU has a higher average benchmark score?

A: The NVIDIA GeForce GTX 675MX has an average benchmark score of 8,427, which is higher than the AMD Radeon Vega 8 Mobile’s 7,203.

Q: How much faster is the GTX 675MX in the Geekbench OpenCL test?

A: The GTX 675MX scores 10,723 versus the Vega 8 Mobile’s 7,435, a 44.2% advantage.

Q: Which GPU supports a newer version of DirectX?

A: The AMD Radeon Vega 8 Mobile supports DirectX 12 (12_1), while the NVIDIA GeForce GTX 675MX supports DirectX 12 (11_0).

Q: What are the TDPs of these two GPUs?

A: The NVIDIA GeForce GTX 675MX has a TDP of 100 W, while the AMD Radeon Vega 8 Mobile has a TDP of 25 W.

Q: Do both GPUs have dedicated memory?

A: No. The NVIDIA GeForce GTX 675MX has 2 GB of GDDR5 memory with a 256-bit bus, while the AMD Radeon Vega 8 Mobile uses system shared memory.

Q: Which GPU has a higher transistor density?

A: The AMD Radeon Vega 8 Mobile has a transistor density of 23.5 million per mm², compared to the NVIDIA GeForce GTX 675MX’s 12.0 million per mm².

The Verdict

The data is unambiguous for raw compute performance. The NVIDIA GeForce GTX 675MX is the faster GPU in every benchmark recorded. It wins the only head-to-head test by 44.2%, and its average score is 17% higher. Anyone choosing between these two strictly on performance should pick the GTX 675MX.

However, the choice is rarely that simple. The GTX 675MX is a 100 W MXM module from 2012 that requires a dedicated slot and has no on-board power connector beyond what the MXM interface provides. The Vega 8 Mobile is a 25 W IGP from 2019 that fits into any Raven Ridge APU system with no extra power or cooling requirements. The Vega 8 supports newer API features, including DirectX 12_1 and Vulkan 1.3, which the GTX 675MX cannot match.

For a user with a laptop that can accommodate a dedicated MXM GPU, the GTX 675MX is the clear choice for compute-heavy applications. Its 44.2% lead in OpenCL and higher average score make it the stronger part. For a user who needs a light, low-power system and only occasional GPU acceleration, the Vega 8 Mobile is adequate. The data shows the GTX 675MX is the faster part, but the Vega 8 Mobile’s lower power draw and modern API support make it the more sensible choice for thin-and-light systems where a 100 W dedicated GPU is simply not an option.