AMD Ryzen Embedded 8640U vs AMD Ryzen Embedded 9900X3D Comparison

FAQ

Q: What are the core and thread counts of the AMD Ryzen Embedded 8640U and the AMD Ryzen Embedded 9900X3D?

A: The Ryzen Embedded 8640U has 6 cores and 12 threads, while the Ryzen Embedded 9900X3D has 12 cores and 24 threads, double the count of each.

Q: Which processor uses a smaller process node?

A: Both processors are built on a 4 nm process node at TSMC, so there is no difference in manufacturing process size.

Q: How much L3 cache does each processor have?

A: The Ryzen Embedded 8640U has 16 MB of shared L3 cache, while the Ryzen Embedded 9900X3D has 128 MB of L3 cache, which is eight times larger.

Q: What are the base and boost clock speeds of the two processors?

A: The Ryzen Embedded 8640U has a base clock of 3.50 GHz and a boost clock of 4.90 GHz. The Ryzen Embedded 9900X3D has a base clock of 4.40 GHz and a boost clock of 5.50 GHz.

Q: Do both processors support ECC memory?

A: Yes, both the Ryzen Embedded 8640U and the Ryzen Embedded 9900X3D support ECC memory.

Q: What is the TDP difference between the two chips?

A: The Ryzen Embedded 8640U has a TDP of 28 watts, whereas the Ryzen Embedded 9900X3D has a TDP of 120 watts.

Architecture Differences

The two processors come from different generations of AMD's embedded lineup. The Ryzen Embedded 8640U belongs to the 8000 series and uses the Zen 4 architecture under the codename Hawk Point. The Ryzen Embedded 9900X3D belongs to the 9000 series and uses the Zen 5 architecture under the codename Granite Ridge. This generational gap means the 9900X3D has a newer core microarchitecture, which affects instruction handling and efficiency, although the recorded data does not provide per-architecture IPC measurements.

The transistor counts and die sizes differ substantially. The 8640U integrates 25,000 million transistors on a die size of 178 mm². The 9900X3D uses a dual-chiplet design with two dies, each measuring 70.6 mm², for a combined die area of roughly 141.2 mm², and carries 16,630 million transistors. The 9900X3D achieves a higher transistor density on a smaller total silicon area, which aligns with the newer Zen 5 design.

Cache hierarchies are a major architectural divergence. The 8640U has 64 KB of L1 cache per core, 1 MB of L2 cache per core, and 16 MB of shared L3 cache. The 9900X3D has 80 KB of L1 cache per core, 1 MB of L2 cache per core, and 128 MB of L3 cache. The 9900X3D's L3 cache is eight times larger, a feature consistent with the X3D branding that emphasizes large cache capacity for data-heavy workloads. The per-core L1 cache is also 16 KB larger on the 9900X3D.

Memory support is identical in specification: both use DDR5 memory with a dual-channel bus and a memory bandwidth of 89.6 GB/s. Both also support ECC memory. PCIe connectivity differs, with the 8640U providing Gen 4 over 20 lanes (CPU only), while the 9900X3D provides Gen 5 over 24 lanes (CPU only). The 9900X3D therefore offers a newer PCIe standard and four additional lanes.

Integrated graphics differ as well. The 8640U uses a Radeon 760M, while the 9900X3D uses a generic Radeon Graphics solution. The market segment classifications also separate the two: the 8640U is listed under Mobile, while the 9900X3D is listed under Desktop. The 9900X3D has an unlocked multiplier, whereas the 8640U does not, indicating overclocking capability on the desktop part. The 9900X3D has a known part number (100-000001368E), while the 8640U's part number is listed as unknown.

Head-to-Head Benchmarks

The database contains no recorded benchmark scores for either processor. Both chips have an average benchmark score of 0 and a percentile versus all CPUs of 50. With no head-to-head benchmark entries, there are no measured wins for either side, and no deltas can be calculated from nearest rivals. The data does not provide any multi-core, single-core, or synthetic workload results to compare.

Because benchmark results are absent, the analysis must rely on specification-level differences to infer relative positioning. The 9900X3D doubles the core and thread count, offering 12 cores and 24 threads versus 6 cores and 12 threads. It also operates at higher clocks: 4.40 GHz base and 5.50 GHz boost versus 3.50 GHz base and 4.90 GHz boost. The boost clock advantage of 0.60 GHz and the base clock advantage of 0.90 GHz, combined with double the cores, point toward a substantial multi-threaded performance lead for the 9900X3D in workloads that scale with core count.

The 8640U counters with a much lower TDP of 28 watts versus 120 watts. That 92-watt gap indicates the 8640U is designed for power-constrained environments, where sustained performance per watt is prioritized over absolute throughput. The 9900X3D's larger L3 cache (128 MB versus 16 MB) gives it a clear edge in cache-sensitive workloads, such as certain database operations or large working sets, though no benchmark data in the database confirms this directly.

The PCIe generation difference also favors the 9900X3D for I/O heavy tasks. Gen 5 offers double the bandwidth per lane compared to Gen 4, and the 9900X3D has 24 lanes versus 20 lanes on the 8640U. For embedded applications that move large amounts of data across the bus, this is a meaningful specification advantage. The 8640U's mobile segment classification and integrated Radeon 760M graphics suggest it targets compact, power-efficient systems, while the 9900X3D's desktop classification, unlocked multiplier, and dual-die design target high-performance embedded workstations.

Without recorded measurements, any performance ranking must be considered provisional. The specification data alone shows the 9900X3D ahead in core count, clock speed, cache size, PCIe capability, and newer architecture. The 8640U leads in power efficiency and smaller physical footprint, based on its 28-watt TDP and single-die 178 mm² configuration.

Specification Differences

The two processors differ across nearly every major specification field in the database.

• Cores: 6 (8640U) versus 12 (9900X3D)
• Threads: 12 versus 24
• Base clock: 3.50 GHz versus 4.40 GHz
• Boost clock: 4.90 GHz versus 5.50 GHz
• TDP: 28 watts versus 120 watts
• Socket: AMD Socket FP8 versus AMD Socket AM5
• Architecture: Zen 4 versus Zen 5 (per generation field)
• Codename: Hawk Point versus Granite Ridge
• Series: 8000 series versus 9000 series
• Generation: Ryzen Embedded (Zen 4, Hawk Point) versus Ryzen Embedded (Zen 5, Granite Ridge)
• Transistors: 25,000 million versus 16,630 million
• Die size: 178 mm² versus 2x 70.6 mm²
• L1 cache per core: 64 KB versus 80 KB
• L3 cache: 16 MB shared versus 128 MB
• PCIe: Gen 4, 20 lanes versus Gen 5, 24 lanes
• Integrated graphics: Radeon 760M versus Radeon Graphics
• Market segment: Mobile versus Desktop
• Multiplier unlocked: No versus Yes
• Part number: Unknown versus 100-000001368E
• Release date: 2024-04-01 versus 2025-10-06

Fields that are identical include the manufacturer (AMD), process node (4 nm), foundry (TSMC), memory support (DDR5), memory bus (dual-channel), memory bandwidth (89.6 GB/s), ECC memory support (true), L2 cache per core (1 MB), and production status (Active). Neither processor has a recorded launch MSRP in the database.

The Verdict

The data paints a clear picture of two processors aimed at different ends of the embedded spectrum. The AMD Ryzen Embedded 9900X3D is the higher-performance part on every computational specification: double the cores, double the threads, higher base and boost clocks, eight times the L3 cache, a newer Zen 5 architecture, and a faster PCIe Gen 5 interface with more lanes. Its TDP of 120 watts reflects the power budget required to feed those resources.

The AMD Ryzen Embedded 8640U is the efficiency-oriented choice. Its 28-watt TDP is less than a quarter of the 9900X3D's power draw, and its single-die design on a 178 mm² package suits space-constrained mobile systems. The Radeon 760M integrated graphics and FP8 socket further align with compact, low-power embedded deployments.

For workloads that demand maximum compute density, large cache capacity, or high-bandwidth I/O, the 9900X3D is the only option between the two based on recorded specifications. For systems where heat dissipation and power delivery are limited, the 8640U's 28-watt envelope is the decisive factor. The absence of recorded benchmark scores means the database cannot confirm the magnitude of the performance gap, but the specification delta is unambiguous: the 9900X3D dominates in raw capability, while the 8640U dominates in efficiency.