Intel Xeon 6521P vs Intel Xeon w7-3565X Comparison

FAQ

Q: Which processor has more cores and threads?

A: The Intel Xeon w7-3565X has 32 cores and 64 threads, while the Intel Xeon 6521P has 24 cores and 48 threads. The w7-3565X also offers 32 additional PCIe lanes (112 versus 136 is actually fewer, so the 6521P has more lanes).

Q: How do the two chips compare in Cinebench multi-core scores?

A: The Xeon w7-3565X leads in every Cinebench multi-core test by 6%. In Cinebench R23 multi-core, it scores 60045 versus 56658 for the Xeon 6521P; in R20 multi-core, 25218 versus 23796; and in R15 multi-core, 6052 versus 5711.

Q: Which processor wins in single-threaded workloads?

A: The Xeon w7-3565X wins all single-thread tests, with a 6% lead in Cinebench R15, R20, and R23 single-core, and a 5.2% lead in PassMark single-thread (3407 versus 3238).

Q: Are there any benchmarks where the Xeon 6521P comes out ahead?

A: Yes, the 6521P wins PassMark find prime numbers (560 versus 398, a 28.9% advantage) and PassMark physics (5972 versus 4254, a 28.8% advantage). These are the only two wins out of 17 head-to-head tests.

Q: What is the average benchmark score for each processor?

A: The Xeon w7-3565X has an average benchmark score of 118307, while the Xeon 6521P averages 105845. Both sit at the 97th percentile among all CPUs in the database.

Q: Which processor has the larger L3 cache?

A: The Xeon 6521P has 144 MB of shared L3 cache, while the Xeon w7-3565X has 82.5 MB of L3 cache. The 6521P also has a larger L1 cache per core at 112 KB versus 80 KB.

Architecture Differences

The two processors come from different Intel families and process nodes. The Xeon w7-3565X is built on Sapphire Rapids architecture using Intel's 10 nm process, with a die composed of four 477 mm² tiles. The Xeon 6521P employs Granite Rapids architecture on a 5 nm node with a single 598 mm² die. This process shrink allows the 6521P to pack more cache per core despite having fewer cores overall.

The w7-3565X features 32 cores and 64 threads, while the 6521P offers 24 cores and 48 threads. Both use a per-core L2 cache of 2 MB, but the L1 cache differs: the w7-3565X has 80 KB per core, while the 6521P has 112 KB per core. The L3 cache configuration is also distinct: the w7-3565X has 82.5 MB, whereas the 6521P has 144 MB shared across all cores.

Both processors support DDR5 memory with eight-channel memory buses, but the 6521P achieves a higher memory bandwidth of 409.6 GB/s compared to 307.2 GB/s for the w7-3565X. The 6521P also provides more PCIe connectivity with 136 Gen 5 lanes versus 112 for the w7-3565X. Neither chip includes integrated graphics.

The w7-3565X has an unlocked multiplier, enabling overclocking, while the 6521P is locked. The w7-3565X uses Intel Socket 4677, whereas the 6521P uses Intel Socket 4710. The w7-3565X released in August 2024, and the 6521P followed in February 2025. The w7-3565X carries a launch MSRP of $2689, and the 6521P has a launch MSRP of $1250.

Head-to-Head Benchmarks

The data shows a clear overall winner: the Xeon w7-3565X claims 15 of 17 benchmark victories. The margins vary significantly across workload types. In Cinebench tests, the w7-3565X consistently outperforms the 6521P by exactly 6% across all six tests: R15 multi-core (6052 versus 5711), R15 single-core (854 versus 806), R20 multi-core (25218 versus 23796), R20 single-core (3560 versus 3359), R23 multi-core (60045 versus 56658), and R23 single-core (8477 versus 7998). This uniform 6% delta suggests the w7-3565X benefits from its additional 8 cores and 16 threads in multi-threaded rendering, while its higher boost clock of 4.80 GHz versus 4.10 GHz helps in single-threaded tasks.

The PassMark suite reveals where the w7-3565X excels most dramatically. In floating point math, it leads by 22.3% (218720 versus 178828). Extended instructions show a 17.9% advantage (85856 versus 72820). Integer math is 13.4% ahead (279202 versus 246263). Data compression sees an 11.1% lead (1075602 versus 967721). Data encryption is 6.7% better (54676 versus 51221). Random string sorting is 6.1% ahead (110848 versus 104517). The multithread benchmark shows a 6% advantage (70642 versus 66657), matching the Cinebench pattern.

The Xeon 6521P has two notable wins, both substantial. In find prime numbers, it scores 560 versus 398, a 28.9% advantage. In physics, it scores 5972 versus 4254, a 28.8% lead. These results indicate different architectural strengths: the 6521P's larger L3 cache and newer process node benefit certain algorithmic workloads that scale with cache capacity and memory bandwidth.

The single-thread PassMark results show a narrower gap of 5.2% (3407 versus 3238), consistent with the Cinebench single-core deltas. The average benchmark score difference is larger: the w7-3565X averages 118307, which is 11.8% above the 6521P's 105845 average.

Specification Differences

The processors differ in core count (32 versus 24), thread count (64 versus 48), base clock (2.50 GHz versus 2.60 GHz), and boost clock (4.80 GHz versus 4.10 GHz). The w7-3565X has a TDP of 335 watts, while the 6521P draws 225 watts.

The socket types differ: the w7-3565X uses Intel Socket 4677, and the 6521P uses Intel Socket 4710. The architecture differs as well: Sapphire Rapids with a 10 nm process and four 477 mm² dies for the w7-3565X, versus Granite Rapids with a 5 nm process and a single 598 mm² die for the 6521P.

Cache configurations diverge: the w7-3565X has 80 KB L1 per core and 82.5 MB L3, while the 6521P has 112 KB L1 per core and 144 MB shared L3. Both have 2 MB L2 per core. Memory bandwidth favors the 6521P at 409.6 GB/s versus 307.2 GB/s, despite both using eight-channel DDR5.

PCIe lane counts differ: 112 lanes for the w7-3565X versus 136 lanes for the 6521P, both Gen 5. The w7-3565X has an unlocked multiplier; the 6521P does not. Release dates differ (August 2024 versus February 2025). The w7-3565X part number is SRN73; the 6521P is SRVNS.

The Verdict

The benchmark data makes a straightforward case: the Xeon w7-3565X is the stronger performer in the majority of tested workloads, winning 15 of 17 head-to-head comparisons. Its average benchmark score of 118307 places it 11.8% above the 6521P's 105845 average. The w7-3565X is the clear choice for multi-threaded compute tasks, rendering, and general server workloads where its 32 cores and higher boost clock translate into consistent 6% gains across Cinebench and PassMark multithread tests.

The Xeon 6521P, however, demonstrates that raw core count is not the only factor. Its wins in find prime numbers and physics, both by nearly 29%, suggest that its 144 MB L3 cache, higher memory bandwidth of 409.6 GB/s, and 5 nm process node provide advantages in cache-sensitive and memory-bound algorithms. The 6521P also consumes less power at 225 watts TDP versus 335 watts, which may be relevant for dense server deployments.

The verdict depends on workload mix. For general-purpose server workloads, database operations, and multi-threaded applications, the w7-3565X offers better all-around performance. For workloads specifically optimized for large caches or memory bandwidth, the 6521P can outperform despite having fewer cores. The w7-3565X also offers overclocking capability, while the 6521P does not.

Where Each One Wins

The Xeon w7-3565X wins in rendering workloads, as shown by its 6% lead across all Cinebench R15, R20, and R23 tests, both multi-core and single-core. It also wins in floating point math with a 22.3% advantage, making it suitable for scientific computing and simulation tasks. Integer math workloads see a 13.4% lead, benefiting general data processing. Extended instruction workloads show a 17.9% advantage, useful for cryptography and vectorized code. Data compression is 11.1% faster, and data encryption is 6.7% faster, making the w7-3565X the better choice for storage and security-related server tasks. Random string sorting is 6.1% ahead, and the overall multithread benchmark favors the w7-3565X by 6%.

The Xeon 6521P wins specifically in prime number finding by 28.9% and physics simulations by 28.8%. These two workloads indicate that the 6521P's larger L3 cache and higher memory bandwidth deliver measurable benefits in algorithms that repeatedly access large datasets. The 6521P also has a higher base clock of 2.60 GHz versus 2.50 GHz, which may help in lightly threaded workloads that do not boost as aggressively. Its lower TDP of 225 watts makes it more power-efficient per core, though the database does not include efficiency ratios for direct comparison.

For users selecting between these processors, the w7-3565X is the safer choice for diverse server workloads, while the 6521P is attractive for specialized workloads that exploit its cache hierarchy and memory subsystem. Both processors rank at the 97th percentile among all CPUs, so neither is a weak option; the choice hinges on which benchmark patterns match the intended use case.