AMD EPYC 7643P vs Intel Xeon 676X Comparison

# Head-to-Head Benchmarks

The Intel Xeon 676X dominates the head-to-head comparison, winning 13 of the 16 benchmark categories against the AMD EPYC 7643P. The most decisive victories come in single-threaded and extended instruction workloads. In PassMark's single-thread test, the Xeon 676X scores 4015 versus the EPYC's 2655, a 51.2% advantage. That gap carries over to Cinebench single-core tests, where the Xeon wins every iteration by exactly 17.9% — R15 scores 1101 to 934, R20 scores 4591 to 3895, and R23 shows the same proportional lead.

Multi-core rendering tells a similar story, though the margins are more modest. In Cinebench R23 multi-core, the Xeon 676X posts 77447 against the EPYC's 65710, again a 17.9% delta. The pattern repeats across R15 (7806 vs 6623) and R20 (32527 vs 27598), with identical 17.9% differentials. PassMark's multithread score reflects this too: 91115 for Intel versus 77307 for AMD, another 17.9% gap. The consistency of this margin across all three Cinebench generations suggests a fundamental throughput advantage rather than workload-specific optimization.

The Xeon's largest single win is in extended instructions, where it scores 105231 compared to 67398 — a commanding 56.1% lead. Floating-point math also favors Intel heavily, with 283570 versus 216592, a 30.9% edge. Prime number finding goes to the Xeon at 738 versus 651 (13.4% ahead), and physics simulation shows a narrower 3.5% win (8281 vs 8002). Data compression is close but still favors Intel: 1355807 to 1326051, just 2.2% apart.

The AMD EPYC 7643P secures three wins, and they are notable for their specificity. Data encryption is the EPYC's strongest category, scoring 95606 against the Xeon's 67638 — a 29.3% advantage in AMD's favor. Integer math also goes to AMD, 390775 versus 354777, a 9.2% lead. Random string sorting completes AMD's trifecta with 160274 against 137976, a 13.9% margin. These wins cluster around memory-intensive and integer-heavy operations, hinting at architectural strengths that the broader benchmark suite does not capture.

# Architecture Differences

The two processors come from fundamentally different design philosophies. The Intel Xeon 676X uses the Granite Rapids architecture on a 5 nm process fabricated by Intel, while the AMD EPYC 7643P relies on Zen 3 (Milan) on a 7 nm process from TSMC. Intel's die size is listed as 2x 598 mm², whereas AMD's configuration uses 8x 81 mm² chiplets — a multi-die approach that spreads 33,200 million transistors across smaller silicon tiles.

Core counts differ substantially: the Xeon 676X packs 32 cores and 64 threads, while the EPYC 7643P offers 48 cores and 96 threads. Despite the EPYC's 50% core advantage, the Xeon still wins most benchmarks, indicating higher per-core efficiency. Clock speeds reinforce this: Intel's base clock is 2.80 GHz with a boost of 4.90 GHz, compared to AMD's 2.30 GHz base and 3.60 GHz boost. The Xeon's 1.30 GHz higher boost ceiling explains much of its single-thread dominance.

Cache hierarchies also diverge sharply. The Xeon provides 112 KB L1 and 2 MB L2 per core, with 144 MB of shared L3. AMD's design uses 64 KB L1 and 512 KB L2 per core, but compensates with a much larger 256 MB shared L3 pool. The EPYC's extra L3 capacity likely supports its strong data encryption and random string sorting results, where larger working sets benefit from more on-die storage.

Memory infrastructure follows different generations. The Xeon 676X supports DDR5 across an eight-channel bus, delivering 409.6 GB/s of bandwidth. The EPYC 7643P uses DDR4, also eight-channel, but with half the bandwidth at 204.8 GB/s. PCIe connectivity differs as well: Intel offers Gen 5 with 128 lanes, while AMD provides Gen 4 with the same lane count. Both support ECC memory, but the EPYC's older memory standard limits its theoretical data movement capabilities.

Other notable differences: Intel's package is Socket 4710, AMD's is Socket SP3. The Xeon has an unlocked multiplier; the EPYC does not. Intel's TDP is 275 watts versus AMD's 225 watts. The Xeon lists a launch date of February 2026, while the EPYC launched in September 2023. Intel's part number is SA2CY; AMD's is 100-000001285.

# FAQ

Q: Which processor wins more benchmarks overall?

A: The Intel Xeon 676X wins 13 of 16 head-to-head tests, with the AMD EPYC 7643P winning 3.

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

A: In PassMark single-thread testing, the Xeon 676X scores 4015 versus the EPYC 7643P's 2655, a 51.2% lead. Cinebench single-core tests show a consistent 17.9% advantage across R15, R20, and R23.

Q: Does the EPYC 7643P win any benchmarks?

A: Yes, it wins in data encryption (95606 vs 67638, a 29.3% margin), integer math (390775 vs 354777, a 9.2% lead), and random string sorting (160274 vs 137976, a 13.9% edge).

Q: Why does the EPYC lose despite having more cores?

A: The EPYC has 48 cores versus the Xeon's 32, but the Xeon's higher clock speeds (4.90 GHz boost vs 3.60 GHz) and newer DDR5 memory with 409.6 GB/s bandwidth versus 204.8 GB/s compensate for the core deficit.

Q: What is the largest benchmark margin in either direction?

A: The Xeon's extended instructions score of 105231 beats the EPYC's 67398 by 56.1%, the biggest single delta. The EPYC's largest win is data encryption at 29.3%.

Q: How do these processors compare to other CPUs in their class?

A: The Xeon 676X sits at the 98th percentile of all CPUs, with its closest rival being the AMD EPYC 9355P at -1.1% delta. The EPYC 7643P also ranks at the 98th percentile, with the Intel Xeon w9-3575X as its nearest rival at +0.3%.

# Specification Differences

| Field | Intel Xeon 676X | AMD EPYC 7643P |

|-------|----------------|----------------|

| Cores | 32 | 48 |

| Threads | 64 | 96 |

| Base Clock | 2.80 GHz | 2.30 GHz |

| Boost Clock | 4.90 GHz | 3.60 GHz |

| TDP | 275 W | 225 W |

| Socket | Intel Socket 4710 | AMD Socket SP3 |

| Architecture | Granite Rapids | Zen 3 |

| Process Node | 5 nm | 7 nm |

| Foundry | Intel | TSMC |

| Die Size | 2x 598 mm² | 8x 81 mm² |

| L1 Cache | 112 KB per core | 64 KB per core |

| L2 Cache | 2 MB per core | 512 KB per core |

| L3 Cache | 144 MB shared | 256 MB shared |

| Memory Support | DDR5 | DDR4 |

| Memory Bandwidth | 409.6 GB/s | 204.8 GB/s |

| PCIe Version | Gen 5 | Gen 4 |

| PCIe Lanes | 128 (CPU only) | 128 (CPU only) |

| Multiplier Unlocked | Yes | No |

| Launch MSRP | $2499 | $2722 |

# Where Each One Wins

The Intel Xeon 676X is the clear choice for workloads that depend on single-thread performance, high clock speeds, and memory bandwidth. Its 51.2% lead in single-thread testing and 30.9% advantage in floating-point math make it well-suited for scientific computing, simulation, and rendering tasks. The 56.1% edge in extended instructions suggests strong vectorized and specialized instruction handling, which benefits engineering software and media processing. The Xeon also wins every Cinebench multi-core test, so content creation and 3D rendering pipelines that scale across threads will favor Intel's architecture.

The AMD EPYC 7643P carves out a narrower but real niche. Its 29.3% win in data encryption points to hardware acceleration or more efficient cryptographic operations, making it attractive for security-focused workloads like VPN termination, SSL/TLS processing, and database encryption. The 9.2% integer math advantage indicates strength in general-purpose compute tasks such as data processing and business applications. Random string sorting, where AMD leads by 13.9%, suggests the larger 256 MB L3 cache helps with sorting algorithms and text processing workloads that benefit from extensive on-die data residency.

For memory bandwidth-bound applications, the Xeon's DDR5 support doubling the EPYC's bandwidth (409.6 GB/s vs 204.8 GB/s) provides a structural advantage. However, the EPYC's 48 cores and 96 threads offer more parallelism for workloads that scale linearly with thread count, even if per-core performance is lower. The EPYC's lower TDP of 225 watts versus 275 watts also means less heat generation in dense server deployments.

# The Verdict

The benchmark data presents a clear overall winner: the Intel Xeon 676X outperforms the AMD EPYC 7643P in 13 of 16 tests, with an average benchmark score of 158540 versus 144824. The Xeon's advantages span rendering, single-thread, floating-point, and extended instruction workloads, often by substantial double-digit margins. Its higher clock speeds and newer DDR5 memory infrastructure translate directly into benchmark wins across the board.

However, the EPYC 7643P is not without merit. Its wins in encryption, integer math, and string sorting — plus its 48 cores and 256 MB L3 cache — make it a rational choice for specific deployment scenarios. If the workload is dominated by cryptographic operations or involves large datasets that benefit from massive cache residency, the EPYC's targeted strengths may outweigh its overall deficit.

The decision hinges on workload composition. For mixed or rendering-heavy environments, the Xeon 676X's comprehensive benchmark dominance, including 17.9% leads across all Cinebench tests and 30.9% in floating-point math, makes it the data-backed recommendation. For security-focused or integer-heavy server workloads where the EPYC's 29.3% encryption win and 9.2% integer math advantage matter more than raw single-thread speed, the EPYC 7643P remains competitive. Both processors sit at the 98th percentile of all CPUs, but the Xeon 676X's higher average score and broader win profile position it as the stronger all-round choice.