Intel Xeon 6780E vs Intel Xeon 6781P Comparison

The Intel Xeon 6781P and Intel Xeon 6780E represent two distinct design philosophies within Intel’s Xeon 6 lineup, and the benchmark data reflects a clear division of labor. The 6781P, built on Granite Rapids, prioritizes raw performance per thread and high-frequency operation, while the 6780E, built on Sierra Forest, optimizes for sheer core count and throughput in specific workloads. Out of 14 head-to-head benchmark comparisons, the 6781P claims 10 wins, while the 6780E secures 4, but the nature of those wins reveals which processor belongs in which type of server.

Where Each One Wins

The Intel Xeon 6781P is the overwhelming choice for compute-intensive and latency-sensitive applications. Its largest victories come in workloads that reward high clock speeds and strong single-thread performance. In Cinebench R15, R20, and R23 multi-core tests, the 6781P consistently outperforms the 6780E by exactly 36% in each case, scoring 10,105 vs 7,431, 42,106 vs 30,963, and 100,254 vs 73,723 respectively. This pattern extends to PassMark’s multithread test, where the 6781P again leads by 36% with a score of 117,946 against 86,734. The single-thread gap is even more pronounced: the 6781P scores 3,152 versus 1,923 in PassMark’s single-thread test, a 63.9% advantage that directly stems from its higher boost clock.

The 6781P also dominates in specialized instruction workloads. In PassMark’s extended instructions test, it scores 199,048 versus 114,008 for the 6780E, a massive 74.6% lead. Prime number finding shows the 6781P at 1,687 versus 708, a 138.3% advantage, and physics calculations favor the 6781P at 17,753 versus 10,951, a 62.1% margin. Floating-point math also goes to the 6781P, with scores of 507,406 against 433,862, a 17% lead. These results indicate the 6781P is the superior part for scientific computing, financial modeling, and any workload where individual thread performance matters more than raw core count.

The Intel Xeon 6780E wins in four specific areas, all of which involve memory-intensive or integer-heavy parallel operations. Its most significant victory is in data encryption, where it scores 193,004 versus 119,623 for the 6781P, a 38% advantage. Data compression also favors the 6780E, with scores of 2,557,582 against 2,441,690, a 4.5% margin. Random string sorting shows a 17.9% lead for the 6780E (326,954 vs 268,573), and integer math goes to the 6780E at 641,817 versus 584,834, an 8.9% difference. These wins align with the 6780E’s higher core count (144 vs 80) and its larger L2 cache per module, which helps in workloads that can leverage massive parallelism without requiring high per-thread clocks.

Architecture Differences

The two processors diverge fundamentally in their underlying architecture. The Intel Xeon 6781P uses the Granite Rapids architecture, which is a performance-optimized design with 80 cores and 160 threads. Its base clock is 2.00 GHz, but it boosts to 3.80 GHz, giving it a substantial frequency advantage over the 6780E. The 6780E, based on Sierra Forest, is a efficiency-focused design with 144 cores but only 144 threads, meaning it lacks simultaneous multithreading entirely. Its base clock is higher at 2.20 GHz, but its boost clock is significantly lower at 3.00 GHz, capping its per-thread performance.

Cache configurations highlight the differing philosophies. The 6781P has 112 KB of L1 cache per core, 2 MB of L2 cache per core, and a massive 336 MB of shared L3 cache. The 6780E offers 96 KB of L1 per core, 4 MB of L2 per module, but only 108 MB of shared L3 cache. This means the 6781P has over three times the L3 cache, which is critical for workloads with large working sets. The 6780E compensates with more L2 cache per module, but the total cache hierarchy favors the 6781P for data reuse.

Both processors are built on Intel’s 5 nm process node and share the same Intel Socket 4710. However, their die sizes differ notably: the 6781P uses a dual-die design measuring 2x 598 mm², while the 6780E is a single die at 578 mm². Memory support is identical on paper—both support DDR5 with an eight-channel memory bus and 409.6 GB/s of bandwidth—and both support ECC memory. PCIe connectivity differs, with the 6781P offering Gen 5 with 136 lanes (CPU only) versus 88 lanes for the 6780E, giving the 6781P more expansion headroom for accelerators and storage. The 6781P also has a higher TDP at 350W versus 330W for the 6780E, reflecting its higher clock speeds. Release dates and MSRPs differ: the 6780E launched in June 2024 with a launch MSRP of $11,350, while the 6781P launched in February 2025 with a launch MSRP of $8,960.

FAQ

Q: Which processor has more cores?

A: The Intel Xeon 6780E has 144 cores, while the Intel Xeon 6781P has 80 cores. However, the 6781P supports hyperthreading with 160 threads, whereas the 6780E has 144 threads with no SMT.

Q: Why does the 6781P win so many benchmarks despite having fewer cores?

A: The 6781P has a boost clock of 3.80 GHz versus 3.00 GHz for the 6780E, and it features a much larger 336 MB L3 cache versus 108 MB. These factors drive its 63.9% lead in single-thread tests and 36% lead in multi-core Cinebench results.

Q: In what workloads does the 6780E outperform the 6781P?

A: The 6780E wins in data compression (2,557,582 vs 2,441,690), data encryption (193,004 vs 119,623), random string sorting (326,954 vs 268,573), and integer math (641,817 vs 584,834). These are parallel, memory-intensive tasks that scale with core count.

Q: Do both processors support the same memory configuration?

A: Yes, both support DDR5 with an eight-channel memory bus and 409.6 GB/s bandwidth, and both have ECC memory support. The key memory difference is the cache hierarchy, not the DRAM interface.

Q: Which processor has better PCIe connectivity?

A: The Intel Xeon 6781P offers Gen 5 with 136 lanes (CPU only), while the Intel Xeon 6780E offers Gen 5 with 88 lanes (CPU only). The 6781P provides significantly more I/O bandwidth for expansion cards and accelerators.

Q: What is the performance percentile for these parts?

A: Both processors rank in the 99th percentile against all CPUs in the benchmark database, indicating they are top-tier server parts. The 6781P has an average benchmark score of 315,524, while the 6780E averages 280,438.

Specification Differences

The specifications that diverge between the two parts are numerous. Core count: 80 cores for the 6781P versus 144 cores for the 6780E. Thread count: 160 threads versus 144 threads, reflecting the 6781P’s SMT support. Base clock: 2.00 GHz versus 2.20 GHz. Boost clock: 3.80 GHz versus 3.00 GHz. TDP: 350W versus 330W. Architecture: Granite Rapids versus Sierra Forest. Die size: 2x 598 mm² versus 578 mm². L1 cache: 112 KB per core versus 96 KB per core. L2 cache: 2 MB per core versus 4 MB per module. L3 cache: 336 MB shared versus 108 MB shared. PCIe lanes: 136 versus 88. Release date: February 2025 versus June 2024. Part number: SRV5J versus SRPG3. Launch MSRP: $8,960 versus $11,350. Both share the same socket, process node, foundry, memory support, memory bus, memory bandwidth, ECC support, integrated graphics (N/A), market segment, production status, and unlocked multiplier status (false).

Head-to-Head Benchmarks

The largest single benchmark win for the 6781P comes in PassMark’s find prime numbers test, where it scores 1,687 versus 708 for the 6780E, a 138.3% lead. This extreme margin highlights the 6781P’s superior per-thread integer throughput and high boost clock. The extended instructions test shows a 74.6% advantage (199,048 vs 114,008), underscoring the 6781P’s strength in vectorized and specialized instruction sets. Physics calculations favor the 6781P by 62.1% (17,753 vs 10,951), and single-thread performance is 63.9% higher (3,152 vs 1,923). The Cinebench multi-core suite shows consistent 36% leads across R15, R20, and R23, with scores of 10,105, 42,106, and 100,254 respectively. PassMark multithread also shows a 36% lead at 117,946 versus 86,734. Floating-point math gives the 6781P a 17% edge (507,406 vs 433,862).

The 6780E’s biggest win is in data encryption, where it beats the 6781P by 38% (193,004 vs 119,623). This is likely due to the 6780E’s higher core count and the parallel nature of encryption algorithms. Random string sorting shows a 17.9% lead for the 6780E (326,954 vs 268,573), and integer math gives it an 8.9% edge (641,817 vs 584,834). Data compression is the closest contest, with the 6780E winning by only 4.5% (2,557,582 vs 2,441,690). These four wins demonstrate that the 6780E excels when the workload can fully utilize its 144 physical cores without requiring high clock speeds. The benchmark data collectively shows that the 6781P is the higher-performance part for most workloads, while the 6780E is a specialized tool for specific parallel tasks where its core count advantage translates into measurable gains.