Intel Xeon 6747P vs Intel Xeon 6781P Comparison

The Verdict

The Intel Xeon 6781P is the clear performance leader in nearly every recorded workload, winning 12 of the 14 head-to-head comparisons against the Intel Xeon 6747P. The data shows a processor built for maximum parallel throughput, with its 80 cores and 160 threads delivering decisive advantages in multi-threaded applications. The 6781P’s average benchmark score of 315,524 places it in the 99th percentile of all CPUs, a position shared by the 6747P, but the gap between them is substantial: the 6781P leads its rival by roughly 32% in average score.

However, the verdict is not a simple sweep. The 6747P wins both single-thread tests, with a score of 3,236 versus 3,152 for the 6781P, a 2.6% edge. This suggests that for workloads that depend on per-core speed rather than raw core count, the 6747P holds a subtle but measurable advantage. The 6747P also draws less power on paper, with a TDP of 330 watts versus 350 watts for the 6781P, making it a more efficient option for density-constrained deployments where sustained all-core loads are less common.

For buyers who prioritize maximum multi-core throughput in server or workstation environments, the 6781P is the obvious pick. Its wins in Cinebench R15, R20, and R23 all show a consistent 16% advantage, and its PassMark multi-thread score of 117,946 beats the 6747P’s 101,685 by the same margin. For those who need strong single-thread responsiveness, lower power draw, and a lower launch MSRP ($6,497 versus $8,960), the 6747P offers a compelling alternative, especially if the workload is not fully parallel.

Where Each One Wins

The 6781P dominates in every multi-core metric recorded. In Cinebench R15 multi-core, it scores 10,105 against 8,712, a 16% lead. That pattern repeats in R20 (42,106 versus 36,301) and R23 (100,254 versus 86,432), each with the same 16% delta. The PassMark suite shows even larger gaps in specialized tasks: data compression (2,441,690 versus 1,833,378, up 33.2%), data encryption (119,623 versus 90,789, up 31.8%), extended instructions (199,048 versus 142,557, up 39.6%), and prime number finding (1,687 versus 1,151, up 46.6%). Floating-point math also favors the 6781P heavily, with 507,406 versus 365,904, a 38.7% advantage, and integer math shows a 24.8% lead (584,834 versus 468,518). Physics and random string sorting round out the 6781P’s wins with 32.5% and 48.9% deltas, respectively.

The 6747P wins only in single-threaded performance. Both PassMark single-thread and single-thread (duplicate test names) record a score of 3,236 for the 6747P against 3,152 for the 6781P, a 2.6% advantage. This is a narrow but consistent edge, indicating that the 6747P’s higher base clock of 2.70 GHz (versus 2.00 GHz) and boost clock of 3.90 GHz (versus 3.80 GHz) translate into better per-core responsiveness. For workloads like light database queries, interactive terminal sessions, or latency-sensitive single-threaded services, the 6747P may feel snappier despite having fewer cores.

Architecture Differences

Both processors share the same fundamental architecture: Granite Rapids, a Xeon 6 design on Intel’s 5 nm process node, fabricated by Intel. They use the same socket (Intel Socket 4710), have identical L1 cache per core (112 KB) and L2 cache per core (2 MB), and both support eight-channel DDR5 memory with 409.6 GB/s of bandwidth. ECC memory is standard on both, and neither includes integrated graphics. The die size is also identical at 2x 598 mm², indicating the same physical silicon layout.

The key architectural split is core count and cache. The 6781P packs 80 cores and 160 threads, while the 6747P has 48 cores and 96 threads. That difference drives the multi-core performance gap. The L3 cache also scales with the core count: the 6781P has 336 MB shared, the 6747P has 288 MB. Interestingly, the 6747P’s lower core count allows for higher base and boost clocks, which explains its single-thread win. Both chips are unlocked multiplier? No, both are locked, with `multiplierUnlocked` false.

PCIe lane allocation differs too. The 6781P provides 136 Gen 5 lanes (CPU only), while the 6747P provides 88 lanes. This makes the 6781P more suitable for systems with many high-speed peripherals, GPU accelerators, or NVMe storage devices. The 6747P’s reduced lane count may still be sufficient for typical dual-socket servers, but the 6781P offers more headroom for expansion.

FAQ

Q: Which CPU has more cores and threads?

A: The Intel Xeon 6781P has 80 cores and 160 threads, while the Intel Xeon 6747P has 48 cores and 96 threads.

Q: Does the higher core count always win?

A: No. In single-threaded benchmarks, the 6747P scores 3,236 versus 3,152 for the 6781P, a 2.6% lead. The 6747P’s higher base clock (2.70 GHz versus 2.00 GHz) and boost clock (3.90 GHz versus 3.80 GHz) give it an edge in per-core performance.

Q: What is the difference in L3 cache?

A: The 6781P has 336 MB of shared L3 cache, while the 6747P has 288 MB. Both have the same per-core L1 (112 KB) and L2 (2 MB) caches.

Q: Which CPU has more PCIe lanes?

A: The 6781P offers 136 Gen 5 lanes (CPU only), compared to 88 lanes on the 6747P. This makes the 6781P more suitable for high-bandwidth peripheral configurations.

Q: What are the launch MSRPs?

A: The 6781P has a launch MSRP of $8,960, and the 6747P has a launch MSRP of $6,497.

Q: Are both CPUs in the same performance percentile?

A: Yes, both are in the 99th percentile of all CPUs. However, the 6781P’s average benchmark score is 315,524, while the 6747P’s is 238,263, a 32% gap in overall throughput.

Head-to-Head Benchmarks

The most striking wins for the 6781P come in PassMark’s specialized tests. Random string sorting shows a 48.9% advantage (268,573 versus 180,382), and prime number finding is up 46.6% (1,687 versus 1,151). Extended instructions follow closely at 39.6% (199,048 versus 142,557), with floating-point math at 38.7% (507,406 versus 365,904). These are workloads that scale almost linearly with core count, and the 6781P’s 80 cores simply outmuscle the 6747P’s 48.

Data encryption and compression also favor the 6781P strongly, with 31.8% and 33.2% leads respectively. The encryption score of 119,623 versus 90,789 suggests that the 6781P can handle cryptographic workloads with significantly more headroom. Physics testing shows a 32.5% gap (17,753 versus 13,398), reinforcing the multi-core theme.

The Cinebench suite provides a consistent baseline: all three tests (R15, R20, R23) show exactly 16% deltas in favor of the 6781P. This uniformity indicates that the performance difference is stable across different rendering workloads, not just a single benchmark quirk. The PassMark multi-thread test also lands at 16% (117,946 versus 101,685), matching the Cinebench pattern.

Integer math is less one-sided but still decisively in the 6781P’s favor, with a 24.8% lead (584,834 versus 468,518). This suggests that even integer-heavy workloads, which can be sensitive to clock speed, benefit more from the additional cores than from the 6747P’s higher clocks.

The only reverse result is single-thread performance. Both PassMark single-thread tests (listed under two names) show the 6747P winning by 2.6%, with scores of 3,236 versus 3,152. This is a small but real edge, likely due to the 6747P’s higher base and boost clocks. For users running legacy applications that rely on a single core, the 6747P would be the better choice, but the margin is narrow compared to the multi-core gaps.

Specification Differences

The two CPUs differ in several key specification fields. Core count is the most obvious: 80 cores on the 6781P versus 48 on the 6747P, with thread counts of 160 and 96 respectively. Base clocks are 2.00 GHz for the 6781P and 2.70 GHz for the 6747P, a reversal of the core-count advantage. Boost clocks are closer, at 3.80 GHz versus 3.90 GHz, still favoring the 6747P.

TDP also differs, with the 6781P rated at 350 watts and the 6747P at 330 watts. This 20-watt difference may be relevant for cooling and power budgeting, though both are high-power server parts. The L3 cache scales with core count: 336 MB for the 6781P, 288 MB for the 6747P. PCIe lanes are another differentiator, with 136 lanes on the 6781P versus 88 on the 6747P, both Gen 5 and CPU-only.

The launch MSRPs differ by $2,463, with the 6781P at $8,960 and the 6747P at $6,497. This pricing gap reflects the core and cache advantages of the 6781P, though the 6747P offers a lower entry point for single-thread-sensitive workloads. Both have the same release date, socket, process node, die size, memory support, and ECC capability. Part numbers also differ: SRV5J for the 6781P and SRVEZ for the 6747P.