AMD Radeon Pro 455 vs AMD Radeon RX 550X Comparison

The AMD Radeon Pro 455 and AMD Radeon RX 550X are two end-of-life entries in the database that land within three percentile points of each other, yet the recorded benchmark data gives the Pro 455 a clean sweep in every head-to-head test both parts share. Both GPUs come from AMD's GCN 4.0 architecture on a 14 nm GlobalFoundries process, which makes this a close-family matchup rather than a generational clash. The Pro 455 averages 12831 across its recorded benchmarks and sits at the 52nd percentile against all GPUs in the database; the RX 550X averages 10481 and sits at the 49th percentile. The gap between them, while modest in percentile terms, is consistent across every measurement the database holds.

Head-to-Head Benchmarks

Only two tests exist in the database for both cards, and the Pro 455 wins both. In Geekbench OpenCL the Pro 455 scores 10336 against 9662 for the RX 550X, a 7 percent advantage. In Geekbench Vulkan the margin widens slightly: 12240 versus 11299, an 8.3 percent win for the Pro 455. That is the entire head-to-head record, and it is unambiguous.

The Pro 455 also carries a third benchmark the RX 550X lacks: a Geekbench Metal score of 15916. That figure cannot be compared directly, since the RX 550X has no recorded Metal result, but it lifts the Pro 455's average benchmark score to 12831 across its three tests. The RX 550X, with only OpenCL and Vulkan results, averages 10481.

Context from each card's rival set reinforces the picture. The Pro 455's average of 12831 is statistically indistinguishable from the NVIDIA GeForce GTX 590 at 12830 (a 0 percent delta), marginally behind the AMD FirePro W5100 at 12847 (minus 0.1 percent) and the AMD Radeon 740M at 12870 (minus 0.3 percent), and slightly ahead of the NVIDIA GeForce GTX 670 at 12773 (plus 0.5 percent). The RX 550X's average of 10481 places it ahead of the NVIDIA Tesla C2075 at 10400 (plus 0.8 percent) and the AMD Radeon RX 6500M at 10362 (plus 1.2 percent), while trailing the AMD Radeon R9 M275X at 10582 (minus 1 percent) and the AMD Radeon RX 6600S at 10629 (minus 1.4 percent). In short, the Pro 455 competes in a slightly higher-performing neighborhood, and every shared measurement confirms it beats the RX 550X by single-digit percentages.

Architecture Differences

The family resemblance is strong, but the silicon diverges in meaningful ways. Both use GCN 4.0 and both are fabbed at GlobalFoundries on 14 nm. The Pro 455, built on the Baffin chip, packs 3000 million transistors into a 123 mm² die for a density of 24.4M per mm². The RX 550X uses the smaller Lexa chip: 2200 million transistors across 103 mm², at 21.4M per mm². The Pro 455 simply has more hardware on die.

The execution-resource counts follow the same story. The Pro 455 fields 768 shading units, 48 TMUs, and 16 ROPs. The RX 550X has 512 shading units, 32 TMUs, and the same 16 ROPs. That gives the Pro 455 a clear advantage in theoretical compute: 1313.3 GFLOPS FP32 versus 1211.4 GFLOPS FP32 for the RX 550X, with both cards running FP16 at a 1:1 ratio with FP32. Texture fill rate also favors the Pro 455, 41.04 GTexel/s against 37.86 GTexel/s.

Pixel throughput, however, flips the script. The RX 550X's higher clock speeds (a 1100 MHz base and 1183 MHz boost; the Pro 455's core clocks are not recorded in the database) push its pixel rate to 18.93 GPixel/s, well above the Pro 455's 13.68 GPixel/s. ROP count being equal, the clock advantage decides that metric.

Memory is where the RX 550X claws back ground. It carries 4 GB of GDDR5 on a 128-bit bus running at 1500 MHz (6 Gbps effective), yielding 96.00 GB/s of bandwidth. The Pro 455 has 2 GB of GDDR5 on the same 128-bit bus at 1270 MHz (5.1 Gbps effective), for 81.28 GB/s. The RX 550X therefore offers double the capacity and roughly a fifth more bandwidth, which matters for workloads that exceed a 2 GB frame buffer.

Form factor and power are the other major splits. The Pro 455 is an MXM module with no power connectors, a 35 W TDP, a PCIe 3.0 x8 interface, and portable-device-dependent display outputs, consistent with its Radeon Pro Mac lineage in the 400 Series. The RX 550X is a dual-slot desktop card with no power connectors either, a 50 W TDP, the same PCIe 3.0 x8 bus, and a fixed output stack of one DVI, one HDMI 2.0b, and one DisplayPort 1.4a. Its recorded length is 145 mm. Both support DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3. Neither has RT or tensor cores.

Lineage differs too. The RX 550X belongs to the Polaris generation (RX 500X series), lists Polaris as its predecessor, and has Vega as its successor. The Pro 455 has no recorded predecessor or successor. Release dates are far apart: the Pro 455 arrived on 2016-10-29, the RX 550X on 2018-12-15.

The Verdict

On pure benchmark data, the Pro 455 is the faster card. It wins both shared tests, by 7 percent in OpenCL and 8.3 percent in Vulkan, and posts the higher average score and percentile. Anyone choosing strictly on recorded performance picks the Pro 455.

But the data also tempers that verdict. The margins are single-digit, and the RX 550X answers with 4 GB of memory instead of 2 GB, 96.00 GB/s of bandwidth instead of 81.28 GB/s, and a higher pixel rate of 18.93 GPixel/s versus 13.68 GPixel/s. If a workload is bandwidth-hungry or buffer-limited, the RX 550X's memory subsystem is the stronger foundation despite the weaker compute showing. The Pro 455 is the better compute and texture engine; the RX 550X is the better memory and pixel-pipeline configuration. Both are end-of-life parts with no launch MSRP recorded in the database, so the decision rests entirely on the numbers above.

FAQ

Q: Which card is faster in the shared benchmarks?

A: The Radeon Pro 455 wins both head-to-head tests: Geekbench OpenCL 10336 to 9662 (7 percent) and Geekbench Vulkan 12240 to 11299 (8.3 percent).

Q: How do their average benchmark scores compare?

A: The Pro 455 averages 12831 across three recorded benchmarks; the RX 550X averages 10481 across two. The Pro 455 sits at the 52nd percentile against all GPUs in the database, the RX 550X at the 49th.

Q: Which GPU has more memory?

A: The RX 550X, with 4 GB of GDDR5 versus 2 GB on the Pro 455. Both use a 128-bit bus, but the RX 550X delivers 96.00 GB/s of bandwidth against the Pro 455's 81.28 GB/s.

Q: Do they share the same architecture and manufacturing process?

A: Yes. Both are GCN 4.0 designs fabbed by GlobalFoundries on a 14 nm node, though on different chips: Baffin for the Pro 455 and Lexa for the RX 550X.

Q: Which card has the higher theoretical compute throughput?

A: The Pro 455, at 1313.3 GFLOPS FP32 versus 1211.4 GFLOPS FP32 for the RX 550X, thanks to 768 shading units against 512.

Q: How do their power envelopes differ?

A: The Pro 455 is a 35 W MXM module; the RX 550X is a 50 W dual-slot desktop card with a suggested 250 W system power supply and no power connectors of its own.

Where Each One Wins

The Pro 455's wins map directly onto its hardware advantages. Its 768 shading units and 48 TMUs translate into the higher FP32 figure and the better texture rate, and the benchmark record confirms the translation: 7 percent faster in OpenCL and 8.3 percent faster in Vulkan. General compute workloads, GPU-assisted application tasks, and texture-bound rendering are its territory. Its 35 W MXM packaging also makes it the only option of the two for mobile or compact platform deployments where that form factor applies.

The RX 550X wins nowhere in the recorded benchmark table, but it holds the advantage in every memory- and output-related metric. Its 4 GB frame buffer, 96.00 GB/s of bandwidth, and 18.93 GPixel/s pixel rate make it the better fit for scenarios that need capacity and fill-rate headroom, and as a desktop card it provides tangible display outputs: DVI, HDMI 2.0b, and DisplayPort 1.4a, against the Pro 455's portable-device-dependent outputs. It is also the more recent design, released on 2018-12-15 versus 2016-10-29, and sits in a lineage running from Polaris to Vega.

Specification Differences

• Chip: Baffin (Pro 455) vs Lexa (RX 550X)
• Generation: Radeon Pro Mac, 400 Series vs Polaris, RX 500X
• Transistors: 3000 million vs 2200 million
• Die size: 123 mm² vs 103 mm²
• Transistor density: 24.4M/mm² vs 21.4M/mm²
• Core clocks: not recorded for the Pro 455; 1100 MHz base and 1183 MHz boost for the RX 550X
• Memory size: 2 GB vs 4 GB
• Memory clock: 1270 MHz (5.1 Gbps effective) vs 1500 MHz (6 Gbps effective)
• Memory bandwidth: 81.28 GB/s vs 96.00 GB/s
• Shading units: 768 vs 512
• TMUs: 48 vs 32
• ROPs: 16 on both
• Pixel rate: 13.68 GPixel/s vs 18.93 GPixel/s
• Texture rate: 41.04 GTexel/s vs 37.86 GTexel/s
• FP32/FP16: 1313.3 GFLOPS vs 1211.4 GFLOPS, both FP16 at 1:1
• TDP: 35 W vs 50 W
• Slot width: MXM Module vs Dual-slot
• Suggested PSU: none recorded vs 250 W
• Display outputs: Portable Device Dependent vs 1x DVI, 1x HDMI 2.0b, 1x DisplayPort 1.4a
• Card length: not recorded vs 145 mm
• Release date: 2016-10-29 vs 2018-12-15
• Predecessor/successor: none recorded vs Polaris / Vega
• Benchmarks recorded: Metal 15916, OpenCL 10336, Vulkan 12240 vs OpenCL 9662, Vulkan 11299