AMD EPYC 9634 vs Intel Xeon 678X Comparison

Where Each One Wins

The benchmark data splits this comparison into two very distinct personalities. The AMD EPYC 9634 wins 12 of the 16 head-to-head tests, establishing itself as the dominant force for heavily threaded, data-intensive server workloads. The Intel Xeon 678X counters with 4 wins, all of which reveal a clear single-thread and floating-point advantage that suits different tasks.

The EPYC 9634 builds its case around raw core count and memory bandwidth. With 84 cores and 168 threads, it simply outmasses the Xeon 678X, which offers 48 cores and 96 threads. This translates directly into wins across Cinebench multi-core tests, PassMark multithread, integer math, physics, data compression, encryption, prime number finding, and random string sorting. The margin in integer math is particularly stark at 79.1%, and encryption shows an 81.8% advantage. These are workloads that scale with core count and parallelism, and the EPYC 9634 is clearly the stronger choice.

The Xeon 678X takes a different path. Its wins in PassMark single-thread (3758 vs 2924, a 22.2% advantage), floating-point math (362070 vs 353784, a 2.3% edge), and extended instructions (141431 vs 137543, a 2.7% edge) point to a design that emphasizes per-core efficiency and clock speed. The Xeon boosts to 4.90 GHz compared to 3.70 GHz for the EPYC, and that clock advantage shows in latency-sensitive, lightly threaded applications. The extended instructions result also suggests the Xeon handles specialized instruction sets more efficiently.

The practical split is clear. For database workloads, virtualization hosts, scientific computing, and any application that can saturate 168 threads, the EPYC 9634 is the superior part. For single-threaded responsiveness, certain floating-point-heavy simulations, and applications that cannot scale beyond a handful of threads, the Xeon 678X holds the edge. The data shows two different philosophies: AMD scales up, Intel speeds up.

FAQ

Q: Which processor has more cores and threads?

A: The AMD EPYC 9634 has 84 cores and 168 threads. The Intel Xeon 678X has 48 cores and 96 threads. The EPYC offers exactly 36 additional cores and 72 additional threads.

Q: How large is the single-thread performance gap?

A: In PassMark single-thread testing, the Xeon 678X scores 3758 compared to 2924 for the EPYC 9634. That is a 22.2% advantage for Intel. The Cinebench R23 single-core test tells a different story, however, with the EPYC scoring 12953 against 83775 for the Xeon in multi-core, but for single-core the Xeon does not appear in the Cinebench R23 results for the Xeon, so the PassMark result stands as the clearest single-thread comparison.

Q: Which processor wins in multi-threaded performance?

A: The EPYC 9634 wins every multi-threaded benchmark in the database. Cinebench R23 multi-core shows 91752 for AMD versus 83775 for Intel, a 9.5% margin. PassMark multithread shows 107944 versus 98559, also a 9.5% margin. The EPYC also leads in Cinebench R15 and R20 multi-core by the same 9.5% delta.

Q: How do the two compare in memory bandwidth?

A: The EPYC 9634 supports twelve-channel DDR5 memory with a peak bandwidth of 460.8 GB/s. The Xeon 678X supports eight-channel DDR5 with 409.6 GB/s. The EPYC provides roughly 12.5% more theoretical memory bandwidth, though this figure is not directly benchmarked.

Q: What are the clock speed differences?

A: The Xeon 678X has a base clock of 2.40 GHz and a boost clock of 4.90 GHz. The EPYC 9634 has a base clock of 2.25 GHz and a boost clock of 3.70 GHz. The Xeon boosts 1.20 GHz higher.

Q: Which processor has a higher average benchmark score?

A: The EPYC 9634 has an average benchmark score of 244274, placing it in the 99th percentile of all CPUs. The Xeon 678X has an average score of 193477, also in the 99th percentile. The EPYC is approximately 26.3% higher in average score.

Head-to-Head Benchmarks

The largest single win for the EPYC 9634 comes in PassMark data encryption, where it scores 151943 against 83598 for the Xeon 678X. That is an 81.8% advantage, an enormous margin driven by the EPYC's higher core count and likely its larger shared L3 cache. Integer math follows closely: 725356 versus 405075, a 79.1% lead. These two results alone establish the EPYC as the clear choice for cryptographic workloads and integer-heavy processing.

Random string sorting shows a 59.1% advantage (261134 vs 164102), and physics simulation shows a 57.4% lead (12291 vs 7809). Data compression is another major win at 32.3% (2236412 vs 1690896). Prime number finding rounds out the EPYC's wins with a 16.4% margin (1176 vs 1010).

The Cinebench suite is remarkably consistent. Every Cinebench test, R15, R20, and R23, in both multi-core and single-core variants, shows the EPYC 9634 ahead by exactly 9.5%. This consistency suggests the advantage is structural, a function of core count and cache, rather than workload-specific. The R23 multi-core score of 91752 versus 83775 is the headline number here.

The Xeon 678X takes its wins in three distinct tests plus the duplicate single-thread test. The PassMark single-thread result is the most significant: 3758 versus 2924, a 22.2% advantage. This is the largest win for Intel in the entire comparison. Floating-point math is a narrow win at 362070 versus 353784, just 2.3%. Extended instructions is similarly narrow at 141431 versus 137543, a 2.7% edge.

Notably, the Xeon's single-thread win does not translate to Cinebench single-core. The EPYC wins Cinebench R15 single-core 1305 to 1192 and R20 single-core 5440 to 4967, both by 9.5%. This discrepancy suggests the PassMark single-thread test stresses different aspects of the microarchitecture, possibly clock-dependent integer operations, while Cinebench's rendering workload responds to the EPYC's larger cache and memory subsystem.

The overall pattern is one of scale versus speed. The EPYC 9634 wins 12 tests, many by substantial margins. The Xeon 678X wins 4 tests, three by narrow margins and one by a wide single-thread margin. For most throughput-oriented server deployments, the EPYC's wins are more numerous and more decisive.

Specification Differences

The core and thread counts are the most obvious differentiators. The EPYC 9634 offers 84 cores and 168 threads. The Xeon 678X offers 48 cores and 96 threads. This is a 75% advantage in core count for AMD.

Clock speeds favor Intel significantly. The Xeon 678X runs at a 2.40 GHz base clock and boosts to 4.90 GHz. The EPYC 9634 runs at 2.25 GHz base and 3.70 GHz boost. The Xeon's boost clock is 32% higher, which explains its single-thread dominance.

Thermal design power differs modestly. The Xeon 678X has a TDP of 300 watts. The EPYC 9634 has a TDP of 290 watts. Despite having 36 fewer cores, the Xeon consumes slightly more power, reflecting its higher clock speeds.

Memory architecture differs in channel count. The EPYC 9634 uses twelve-channel DDR5 memory with 460.8 GB/s peak bandwidth. The Xeon 678X uses eight-channel DDR5 with 409.6 GB/s. Both support ECC memory. The EPYC's additional four channels provide 51.2 GB/s more theoretical bandwidth.

Socket compatibility is entirely separate. The EPYC 9634 uses AMD Socket SP5. The Xeon 678X uses Intel Socket 4710. These are not interchangeable platforms.

The Xeon 678X has an unlocked multiplier, allowing overclocking. The EPYC 9634 has a locked multiplier. Server users seeking overclocking headroom will find the Xeon more flexible in this regard, assuming the platform supports it.

The release dates differ by over three years. The EPYC 9634 launched on November 9, 2022. The Xeon 678X launched on February 1, 2026. The EPYC has been available in the market substantially longer.

The EPYC 9634 has a launch MSRP of $10304. The Xeon 678X has a launch MSRP of $3749.

Architecture Differences

The EPYC 9634 is built on AMD's Zen 4 architecture, code-named Genoa, from the EPYC 9004 series. It uses a 5 nm process manufactured by TSMC. The chip is composed of 12 compute dies, each measuring 72 mm², totaling 78,840 million transistors. This chiplet design allows AMD to pack 84 cores while maintaining reasonable yields.

The Xeon 678X uses Intel's Granite Rapids architecture from the Xeon 600 series, specifically Granite Rapids-WS. It also uses a 5 nm process, but fabricated by Intel foundries. The die consists of 2 dies, each measuring 598 mm², for a total of 1196 mm² of silicon. Intel does not report a transistor count for this part.

Cache hierarchies differ substantially. The EPYC 9634 provides 64 KB of L1 cache per core, 1 MB of L2 per core, and a massive 384 MB of shared L3 cache. The Xeon 678X provides 112 KB of L1 per core, 2 MB of L2 per core, and 192 MB of shared L3 cache. The EPYC's L3 cache is exactly double the Xeon's, which contributes to its strong performance in data compression and encryption workloads.

Per-core cache allocation favors Intel. The Xeon provides 112 KB of L1 and 2 MB of L2 per core, versus 64 KB and 1 MB for the EPYC. This gives Intel more private cache per thread, supporting its single-thread advantage.

Memory controllers differ in width. The EPYC 9634 implements a twelve-channel memory bus. The Xeon 678X implements an eight-channel bus. Both support DDR5 and ECC memory. The EPYC's wider bus provides higher peak bandwidth.

PCIe connectivity is identical on paper. Both processors offer Gen 5 PCIe with 128 lanes from the CPU. Neither includes integrated graphics, though the Xeon lists its integrated graphics as "N/A" in the database.

The Xeon 678X has a market segment of Server/Workstation and includes a part number of SA2CX. The EPYC 9634 is also Server/Workstation segment, with part number 100-100000797. Both are listed as Active in production status.

The architectural split is clear: AMD's chiplet-based Zen 4 design maximizes core count and shared cache while Intel's monolithic-die Granite Rapids design emphasizes clock speed and per-core resources. The benchmark data reflects exactly this architectural philosophy.