AMD Radeon R9 M390X vs NVIDIA Tesla K20m Comparison

The Verdict

The data presents a clear split between two very different compute devices. The NVIDIA Tesla K20m holds the overall performance crown, outscoring the AMD Radeon R9 M390X in the only directly comparable head-to-head benchmark. In Geekbench Vulkan, the Tesla K20m scores 21936 against 16951 for the Radeon, a decisive 22.7% advantage. However, the Radeon R9 M390X is not without its own claims, particularly in the Metal API where it posts a strong 24373 score. The Radeon also carries a significantly lower 75W TDP compared to the Tesla's 225W, making it the pragmatic choice for portable or power-constrained systems. Users prioritizing raw compute throughput in a workstation context, where the Tesla's 5 GB of memory and higher shading unit count matter, should favor the NVIDIA part. Those needing a capable mobile GPU with modern API support and efficiency should look to the AMD option.

Architecture Differences

The two GPUs represent fundamentally different design philosophies from their respective manufacturers. The AMD Radeon R9 M390X is built on the Graphics Core Next 3.0 architecture, using the Amethyst chip fabricated on a 28 nm process at TSMC. It packs 5,000 million transistors on a 366 mm² die, yielding a transistor density of 13.7M per mm². The NVIDIA Tesla K20m, by contrast, uses the Kepler architecture with the GK110 chip, also on a 28 nm TSMC process, but scales up to 7,080 million transistors across a much larger 561 mm² die, with a slightly lower density of 12.6M per mm². This gives the Tesla a substantial raw hardware advantage in terms of sheer silicon.

The memory subsystems differ notably. The Radeon features 4 GB of GDDR5 on a 256-bit bus, delivering 160.0 GB/s of bandwidth with memory clocked at 1250 MHz (5 Gbps effective). The Tesla counters with 5 GB of GDDR5 on a wider 320-bit bus, achieving 208.0 GB/s of bandwidth at 1300 MHz (5.2 Gbps effective). This 30% bandwidth advantage for the Tesla is significant for memory-bound workloads.

Compute resources are also skewed toward the Tesla. The NVIDIA part has 2496 shading units, 208 texture mapping units, and 40 render output units, compared to the Radeon's 2048 shaders, 128 TMUs, and 32 ROPs. Consequently, the Tesla achieves higher theoretical rates: 36.71 GPixel/s pixel fillrate and 146.8 GTexel/s texture rate versus 23.14 GPixel/s and 92.54 GTexel/s for the AMD part. FP32 throughput stands at 3.524 TFLOPS for the Tesla, well ahead of the Radeon's 2.961 TFLOPS. Notably, the Radeon offers FP16 at a 1:1 ratio with FP32, while the Tesla lists no FP16 capability.

Connectivity and form factor further differentiate them. The Radeon is an MXM Module with no power connectors and a 75W TDP, designed for portable devices with outputs dependent on the host. The Tesla is a dual-slot, 267 mm (10.5 inches) card requiring both a 6-pin and an 8-pin power connector, with a suggested 550W power supply, and has no display outputs—a pure compute accelerator. The Radeon uses PCIe 3.0 x16, while the Tesla is limited to PCIe 2.0 x16. In API support, the Radeon lists DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.2.170, while the Tesla lists DirectX 12 (11_0), OpenGL 4.6, and a slightly newer Vulkan 1.2.175. The Radeon was released on 2015-05-04, succeeding the Solar System generation, while the Tesla predates it, launching on 2013-01-04, succeeding Tesla Fermi.

Head-to-Head Benchmarks

The single direct comparison available is the Geekbench Vulkan test, where the NVIDIA Tesla K20m emerges as the clear winner. The Tesla scores 21936 points, which is 22.7% higher than the AMD Radeon R9 M390X's score of 16951. This is a substantial margin that underscores the Tesla's architectural advantages in compute-heavy scenarios. The deltaPct of -22.7% is reported from the perspective of the Radeon, meaning the AMD part trails by that percentage.

While the head-to-head data is limited, the broader benchmark landscape from each product's individual results provides additional context. The Radeon R9 M390X achieves a Geekbench Metal score of 24373, which is notably higher than its Vulkan result, suggesting strong performance in Apple's graphics API. The Tesla K20m, on the other hand, has a Geekbench OpenCL score of 16241, which is lower than its Vulkan score of 21936, indicating that its performance varies significantly across compute frameworks.

The average benchmark scores reflect the Tesla's overall edge: the Radeon averages 20662, while the Tesla averages 19089. However, these averages are computed from different benchmark suites (Metal/Vulkan for AMD, OpenCL/Vulkan for NVIDIA), so they are not directly comparable. The percentile rankings tell a similar story: the Radeon sits at the 66th percentile among all GPUs, while the Tesla is at the 64th percentile. This near-parity in percentile ranking, despite the Tesla's Vulkan win, suggests the Radeon's Metal performance boosts its standing.

FAQ

Q: Which GPU is faster in the Geekbench Vulkan benchmark?

A: The NVIDIA Tesla K20m is significantly faster, scoring 21936 compared to the AMD Radeon R9 M390X's 16951, a 22.7% advantage.

Q: How do their memory bandwidths compare?

A: The Tesla K20m has a clear edge with 208.0 GB/s of bandwidth from its 320-bit bus, while the Radeon R9 M390X offers 160.0 GB/s over a 256-bit bus.

Q: What is the power consumption difference?

A: The Radeon R9 M390X has a 75W TDP and requires no power connectors, whereas the Tesla K20m has a 225W TDP and needs both a 6-pin and an 8-pin power connector.

Q: Which GPU has more shading units?

A: The Tesla K20m features 2496 shading units, whereas the Radeon R9 M390X has 2048.

Q: What is the launch MSRP of the Tesla K20m?

A: The Tesla K20m had a launch MSRP of 3,199 USD. The Radeon R9 M390X has no listed launch MSRP.

Q: Which GPU supports a wider range of modern APIs?

A: The Radeon R9 M390X supports DirectX 12 (12_0) and Vulkan 1.2.170, while the Tesla K20m supports DirectX 12 (11_0) and Vulkan 1.2.175. Both support OpenGL 4.6, but the Radeon's DirectX 12 feature level 12_0 is higher than the Tesla's 11_0.

Where Each One Wins

The NVIDIA Tesla K20m wins decisively in raw compute performance. Its 3.524 TFLOPS FP32 throughput, 208.0 GB/s memory bandwidth, and 2496 shading units make it the superior choice for general-purpose GPU computing, scientific simulations, and any workload that leverages OpenCL or Vulkan. The 22.7% Vulkan lead over the Radeon is a strong indicator of its compute dominance. The Tesla also offers more memory (5 GB vs 4 GB), which is critical for large datasets that exceed the Radeon's capacity. Its higher pixel rate (36.71 GPixel/s) and texture rate (146.8 GTexel/s) further cement its position for rendering tasks that are not API-bound.

The AMD Radeon R9 M390X wins in efficiency and portability. Its 75W TDP is one-third of the Tesla's 225W, and its MXM form factor with no power connectors makes it suitable for laptops and compact systems where the Tesla's dual-slot, 267 mm card with external power would be impractical. The Radeon's Geekbench Metal score of 24373, which exceeds its Vulkan score by 44%, indicates strong performance in Apple-centric environments. Its DirectX 12 (12_0) support is also more modern than the Tesla's 11_0 feature level, making it better suited for newer gaming or graphics applications on Windows. The Radeon's FP16 support at 1:1 ratio with FP32 is another differentiator, potentially accelerating workloads that utilize half-precision arithmetic.

In terms of benchmark standings, the Radeon's nearest rivals include the AMD Radeon RX 5600 XT (deltaPct -0.2), Intel Arc A750 (0.4), Intel Arc B570 (0.5), and NVIDIA GeForce RTX 3070 Mobile (0.6). The Tesla's nearest rivals are the NVIDIA GeForce RTX 4050 Mobile (0.2), AMD Radeon RX 6600 (0.3), NVIDIA Quadro K6000 (0.3), and NVIDIA GeForce GTX 780 (-0.4). These proximity scores show that both GPUs are competitive with much newer hardware, though the Tesla's average score of 19089 places it slightly below the Radeon's 20662 average. However, this average is skewed by the different benchmark suites used for each card.

The production status of both is end-of-life, and both are now legacy products. The Radeon's successor is Polaris Mobile, while the Tesla's successor is Tesla Maxwell. For a mobile workstation or a system with strict power and space constraints, the Radeon is the logical pick. For a server or desktop compute node where power is not a concern and maximum throughput is required, the Tesla K20m is the data-backed winner. The choice ultimately comes down to the use case: the Tesla for brute-force compute, the Radeon for efficient, portable graphics with modern API support.