AMD Radeon HD 8790M vs AMD Radeon R7 Graphics Comparison

The Verdict

The benchmark data is unambiguous: the AMD Radeon HD 8790M is the faster GPU in this comparison. It wins both recorded head-to-head tests, with an average benchmark score of 5691 compared to 4998 for the AMD Radeon R7 Graphics. That is a 13.9% advantage in average score, and the discrete mobile card also sits higher in the overall database, at the 33rd percentile versus the 29th percentile for the integrated part. For anyone choosing between these two, the HD 8790M is the performance pick. The R7 Graphics is not without its place, however. Its 25 W TDP and IGP form factor make it suitable for compact systems where a separate graphics module cannot be installed. The data suggests a simple split: the HD 8790M for raw compute throughput, the R7 Graphics for low-power integrated operation. Neither part is current production, both are end-of-life, but the HD 8790M remains the stronger option in every recorded benchmark.

Architecture Differences

The two GPUs come from different generations of the same vendor. The AMD Radeon HD 8790M uses the Mars chip built on GCN 1.0 architecture, while the AMD Radeon R7 Graphics uses the Spectre Lite chip on GCN 2.0. Both are manufactured on a 28 nm process, but the foundries differ: TSMC produces the Mars chip, GlobalFoundries produces Spectre Lite. The transistor counts are starkly different. The R7 Graphics integrates 2,410 million transistors on a 245 mm² die, while the HD 8790M has 950 million transistors on a 77 mm² die. That means the discrete chip has a higher transistor density at 12.3M per mm² versus 9.8M per mm² for the integrated part. The R7 Graphics is a full APU die, which explains the larger size, but the graphics compute resources are identical in count: both have 384 shading units, 24 texture mapping units, and 8 ROPs. The clock behavior diverges from there. The HD 8790M runs at a base of 850 MHz with a boost to 900 MHz, while the R7 Graphics has no recorded base or boost clock, relying instead on system-dependent operation. The memory subsystem is the biggest architectural gap. The HD 8790M has 2 GB of dedicated GDDR5 on a 128-bit bus, delivering 64.00 GB/s of bandwidth. The R7 Graphics uses system shared memory, with system dependent bandwidth and no dedicated VRAM. The API support differs slightly: the HD 8790M exposes DirectX 12 (11_1), while the R7 Graphics supports DirectX 12 (12_0). Both offer OpenGL 4.6 and Vulkan 1.2.170. The HD 8790M uses an MXM-A (3.0) bus interface and an MXM Module slot width, while the R7 Graphics is an IGP with motherboard-dependent outputs.

Where Each One Wins

The recorded benchmarks give the HD 8790M a clean sweep, but the margin matters for use-case interpretation. In Geekbench OpenCL, the HD 8790M scores 5017 against 4015 for the R7 Graphics, a 25% lead. That is a substantial gap for compute workloads that stress raw shader throughput. The HD 8790M also produces higher theoretical rates: 7.200 GPixel/s pixel fill and 21.60 GTexel/s texture fill, compared to 5.760 GPixel/s and 17.28 GTexel/s for the R7 Graphics. FP32 compute is 691.2 GFLOPS versus 553.0 GFLOPS. These numbers point to the HD 8790M being the choice for any task that is fill-rate bound or compute bound. The Vulkan result is closer. The HD 8790M scores 6365 versus 5980 for the R7 Graphics, a 6.4% advantage. The R7 Graphics holds up relatively better in modern API workloads, but it still loses. There is no benchmark category in the database where the R7 Graphics wins. The R7 Graphics does have one clear advantage: power. Its 25 W TDP is recorded, while the HD 8790M has no TDP listed. The integrated part also needs no power connectors, while the HD 8790M has none listed as well, but the MXM module requires a host system designed for it. For a low-power integrated system, the R7 Graphics is the only viable option of the two, but for performance, the HD 8790M is superior in every recorded test.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon HD 8790M has an average benchmark score of 5691, while the AMD Radeon R7 Graphics averages 4998. The HD 8790M also holds a higher percentile rank at 33 versus 29.

Q: How much faster is the HD 8790M in OpenCL compute?

A: The HD 8790M scores 5017 in Geekbench OpenCL compared to 4015 for the R7 Graphics, a 25% advantage.

Q: Does the R7 Graphics win any benchmark?

A: No. In the recorded head-to-head results, the HD 8790M wins both the OpenCL test and the Vulkan test. The R7 Graphics has zero wins.

Q: What memory does each GPU use?

A: The HD 8790M uses 2 GB of dedicated GDDR5 on a 128-bit bus with 64.00 GB/s bandwidth. The R7 Graphics uses system shared memory with system dependent bandwidth.

Q: Are these GPUs from the same architecture generation?

A: No. The HD 8790M uses GCN 1.0 with the Mars chip, while the R7 Graphics uses GCN 2.0 with the Spectre Lite chip. Both are on a 28 nm process but from different foundries.

Q: What is the power draw of the R7 Graphics?

A: The R7 Graphics has a recorded TDP of 25 W. The HD 8790M has no TDP listed in the database.

Head-to-Head Benchmarks

The largest margin in the comparison comes from Geekbench OpenCL. The HD 8790M posts 5017 points, the R7 Graphics posts 4015 points, and the delta is 25%. That is the kind of gap that shows up in real compute tasks such as OpenCL-accelerated filters or physics calculations. The R7 Graphics cannot close that gap with its GCN 2.0 architecture alone, because the shader count is identical and the clock rates are not recorded. The HD 8790M's dedicated GDDR5 memory at 64.00 GB/s is likely a major factor, since the R7 Graphics depends on system memory bandwidth.

The Vulkan test is much tighter. The HD 8790M scores 6365, the R7 Graphics scores 5980, and the delta is only 6.4%. This suggests that in modern API workloads, the architectural generation difference helps the R7 Graphics close some of the gap. The GCN 2.0 part supports DirectX 12 (12_0) while the HD 8790M only reaches DirectX 12 (11_1), which may explain the relatively stronger Vulkan showing. Still, the HD 8790M wins.

Theoretical rates back up the OpenCL result. The HD 8790M achieves 7.200 GPixel/s and 21.60 GTexel/s, versus 5.760 GPixel/s and 17.28 GTexel/s for the R7 Graphics. FP32 throughput is 691.2 GFLOPS for the HD 8790M and 553.0 GFLOPS for the R7 Graphics. Every recorded throughput metric favors the HD 8790M. The only area where the R7 Graphics does not trail is power, where its 25 W TDP is the only recorded figure in the comparison.

The rivalry context reinforces the verdict. The HD 8790M sits within 0.4% of the Intel Iris Pro Graphics P6300, within 0.5% of the NVIDIA GeForce GTX 670MX, and within 0.7% of the NVIDIA GeForce GTX 550 Ti. It is 1.6% ahead of the NVIDIA Quadro M500M. The R7 Graphics, by contrast, sits within 0.4% of the NVIDIA Quadro 4000 and within 0.6% of the NVIDIA GeForce RTX 5060 Ti 16 GB, an odd pairing that reflects the low absolute score. The R7 Graphics trails the AMD Radeon R5 M430 by 0.4% and leads the AMD FirePro W4170M by 0.7%. Neither part is a top performer, but the HD 8790M is clearly the higher-ranked one.

Specification Differences

The two GPUs differ on nearly every specification field where data is recorded. The HD 8790M uses the Mars chip, the R7 Graphics uses Spectre Lite. Architecture is GCN 1.0 versus GCN 2.0. Process node is the same at 28 nm, but foundry differs: TSMC for the HD 8790M, GlobalFoundries for the R7 Graphics. Transistors are 950 million versus 2,410 million, and die size is 77 mm² versus 245 mm². Transistor density is 12.3M per mm² versus 9.8M per mm².

Clocks are a major split. The HD 8790M has a base clock of 850 MHz and a boost clock of 900 MHz, with memory at 1000 MHz or 4 Gbps effective. The R7 Graphics has no recorded base or boost clock and uses system shared memory. Memory capacity is 2 GB GDDR5 on a 128-bit bus with 64.00 GB/s bandwidth for the HD 8790M, versus system shared memory with system dependent bandwidth for the R7 Graphics. Shading units, TMUs, and ROPs are identical at 384, 24, and 8 respectively. Pixel rate is 7.200 GPixel/s for the HD 8790M and 5.760 GPixel/s for the R7 Graphics. Texture rate is 21.60 GTexel/s versus 17.28 GTexel/s. FP32 is 691.2 GFLOPS versus 553.0 GFLOPS. TDP is not listed for the HD 8790M, but the R7 Graphics has a 25 W TDP. Slot width is MXM Module for the HD 8790M and IGP for the R7 Graphics. The HD 8790M has no power connectors listed, while the R7 Graphics has none listed either. Bus interface is MXM-A (3.0) versus IGP. Display outputs are portable device dependent for the HD 8790M and motherboard dependent for the R7 Graphics. DirectX support is 12 (11_1) versus 12 (12_0). OpenGL is 4.6 for both, Vulkan is 1.2.170 for both. Release dates differ, with the HD 8790M appearing earlier and the R7 Graphics later. Both are end-of-life. Neither has a recorded launch MSRP.