AMD EPYC 9634 vs AMD EPYC 9684X Comparison

The AMD EPYC 9684X and AMD EPYC 9634 are both high-end server processors built on the Zen 4 architecture, but they are engineered for distinctly different workloads. The data shows a clear performance hierarchy, with the 9684X holding a 9.3% lead in average benchmark score (266,914 vs 244,274). However, the 9634 is not simply a slower chip; it occupies a different position in the lineup, with the 9684X featuring a massive L3 cache and higher core count, while the 9634 offers a more conventional cache hierarchy and lower power envelope. This analysis breaks down where each processor excels, the architectural reasons for their differences, and what the benchmark results mean for server deployment decisions.

Where Each One Wins

The benchmark results paint a clear picture: the AMD EPYC 9684X is the outright performance king in nearly every measurable category, winning 15 of the 17 head-to-head comparisons. This is not a marginal victory either; the 9684X demonstrates substantial leads in both multi-threaded and single-threaded workloads across the Cinebench suite. In Cinebench R15, R20, and R23, the 9684X consistently wins by margins of 12.6% to 12.7% in both single-core and multi-core tests. This consistency suggests a fundamental clock-for-clock advantage, despite both chips sharing the same 3.70 GHz boost clock.

The 9684X’s dominance extends into specialized workloads. The Passmark physics test shows the most extreme divergence, with the 9684X scoring 24,686 against the 9634’s 12,291 — a staggering 100.8% delta. This test is highly sensitive to cache performance, and the 9684X’s enlarged L3 cache (1152 MB vs 384 MB) provides a massive advantage in simulation and physics calculations that repeatedly access the same data sets. Similarly, the Passmark prime number finding test shows a 71.8% advantage (2,020 vs 1,176), another cache-sensitive workload where the 9684X’s 3x larger cache pays dividends.

For the 9634, its only victories come in the Passmark single-thread tests, where it scores 2,924 versus the 9684X’s 2,891. This 1.1% advantage is small but real. The 9634’s lower core count (84 vs 96) means less thermal contention, allowing its individual cores to sustain slightly higher sustained single-thread performance in certain conditions. This makes the 9634 a marginally better choice for lightly threaded, latency-sensitive applications where that tiny edge matters. However, the 9684X still wins the Cinebench single-core tests by 12.6%, so the 9634’s advantage appears isolated to the Passmark measurement methodology rather than a general single-thread superiority.

Architecture Differences

Both processors are built on TSMC’s 5 nm process node and share the same Zen 4 architecture and Genoa family lineage, but their implementation diverges significantly. The 9684X carries the Genoa-X codename, which signals the inclusion of 3D V-Cache technology. This is reflected in the cache configuration: the 9684X features 1152 MB of shared L3 cache, while the 9634 (codename Genoa) has 384 MB. This 768 MB difference is the single most defining architectural distinction between the two chips, and it explains the 9684X’s dramatic wins in cache-sensitive benchmarks.

The core counts also differ substantially. The 9684X integrates 96 cores and 192 threads, while the 9634 offers 84 cores and 168 threads. This 14.3% core advantage for the 9684X is paired with a higher base clock (2.55 GHz vs 2.25 GHz), though both boost to the same 3.70 GHz. The transistor count tells an interesting story: the 9684X packs 135,240 million transistors versus 78,840 million for the 9634, a 71.5% increase that reflects both the extra cores and the massive on-die cache. Both chips use 12 chiplets (12x 72 mm² die size), but the 9684X’s chiplets contain far more silicon devoted to cache.

Power consumption is another key differentiator. The 9684X has a 400 W TDP, while the 9634 operates at 290 W. This 110 W gap is the price for the additional cores and V-Cache. Both processors share the same AMD Socket SP5 platform, DDR5 memory support with a twelve-channel memory bus, and 460.8 GB/s memory bandwidth. They also both support ECC memory and provide PCIe Gen 5 with 128 lanes from the CPU. Neither chip has integrated graphics, and both are production-active server/workstation parts.

Head-to-Head Benchmarks

The largest margin of victory for the 9684X comes in the Passmark physics test, where it scores 24,686 against the 9634’s 12,291, a 100.8% delta. This doubling of performance is attributable to the V-Cache advantage; physics simulations often involve large working sets that exceed standard cache sizes, and the 9684X’s 1152 MB L3 cache can hold far more of the simulation state on-die, eliminating repeated trips to system memory. The Passmark prime number test shows the second-largest gap at 71.8% (2,020 vs 1,176), again a cache-sensitive workload where the 9684X excels.

In floating-point math, the 9684X scores 472,174 versus 353,784, a 33.5% advantage. This workload benefits from both the higher core count and the larger cache, allowing more parallel floating-point operations to proceed without memory stalls. Random string sorting shows a similar 33.7% gap (349,126 vs 261,134), which is particularly relevant for database and data-processing workloads. Extended instructions test shows a 29.4% delta (177,956 vs 137,543), indicating the 9684X handles AVX-512-style workloads more efficiently.

Data compression shows a 20.7% advantage for the 9684X (2,698,807 vs 2,236,412), while data encryption shows a 17.4% gap (178,453 vs 151,943). Integer math is 16.4% higher (844,145 vs 725,356), and multithread performance is 12.6% higher (121,595 vs 107,944). The Cinebench suite consistently shows 12.6% to 12.7% advantages for the 9684X across all versions and core counts, which aligns closely with the core count delta. The only counterpoint is the Passmark single-thread test, where the 9634 ekes out a 1.1% win (2,924 vs 2,891), suggesting its lower core count allows for marginally better per-core thermal headroom in this specific benchmark.

FAQ

Q: Which processor has more L3 cache?

A: The AMD EPYC 9684X has 1152 MB of shared L3 cache, while the AMD EPYC 9634 has 384 MB. This threefold difference is the primary architectural distinction between the two.

Q: Are both processors compatible with the same motherboard platform?

A: Yes, both use the AMD Socket SP5 and support DDR5 memory with a twelve-channel memory bus. They also both provide PCIe Gen 5 with 128 lanes from the CPU.

Q: Does the 9684X always beat the 9634 in every benchmark?

A: No. While the 9684X wins 15 of 17 head-to-head comparisons, the 9634 wins the Passmark single-thread test with a score of 2,924 versus 2,891, a 1.1% margin.

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

A: The 9684X has a 400 W TDP, while the 9634 operates at 290 W. The 110 W difference reflects the 9684X’s extra 12 cores and significantly larger cache.

Q: How much faster is the 9684X in the Passmark physics test?

A: The 9684X scores 24,686 versus the 9634’s 12,291, representing a 100.8% advantage — the largest performance gap between the two processors.

Q: Do both processors have the same boost clock?

A: Yes, both boost to 3.70 GHz. However, the 9684X has a higher base clock at 2.55 GHz compared to the 9634’s 2.25 GHz.

Specification Differences

The two processors differ in several key specification fields. Core count is the most obvious: the 9684X has 96 cores and 192 threads, while the 9634 has 84 cores and 168 threads. The base clock differs, with the 9684X at 2.55 GHz and the 9634 at 2.25 GHz, though both share a 3.70 GHz boost clock. The TDP is notably higher for the 9684X at 400 W versus 290 W for the 9634.

The L3 cache is the most dramatic divergence: 1152 MB for the 9684X versus 384 MB for the 9634. Transistor count reflects this, with the 9684X carrying 135,240 million transistors versus 78,840 million for the 9634. The codename differs (Genoa-X vs Genoa), as does the release date: the 9684X launched on 2023-06-12, while the 9634 launched earlier on 2022-11-09. The launch MSRP is $14756 for the 9684X and $10304 for the 9634. Part numbers also differ: 100-100000892 for the 9684X and 100-100000797 for the 9634.

All other specifications are identical: both use the Zen 4 architecture, 5 nm process, TSMC foundry, 12x 72 mm² die size, 64 KB L1 and 1 MB L2 per core, DDR5 memory, twelve-channel memory bus, 460.8 GB/s bandwidth, ECC support, PCIe Gen 5 with 128 lanes, and the AMD Socket SP5. Both lack integrated graphics and are production-active server/workstation parts.