Intel Core Ultra 9 285K vs Intel Xeon 6520P Comparison

Where Each One Wins

The Intel Xeon 6520P and Intel Core Ultra 9 285K are both 24-core parts, but they target completely different workloads. The recorded benchmark splits show 8 wins for the Xeon and 9 for the Core Ultra, but the nature of those wins tells the real story.

The Xeon 6520P dominates in sustained heavy compute. Its Cinebench R23 multi-core score of 53495 beats the Core Ultra 9 285K's 42522 by 25.8%. That is a massive gap for a rendering workload that scales with core count and memory bandwidth. The Xeon also wins integer math by 24.3% (214288 vs 172379) and physics by 83.1% (7209 vs 3938). These are workloads where the Xeon's 48 threads and 144 MB of shared L3 cache provide a clear advantage.

The Core Ultra 9 285K fights back in more consumer-oriented tasks. It wins PassMark multi-thread overall (67260 vs 62936, a 6.4% edge), floating-point math by 27.4% (224324 vs 162862), and data encryption by 21.7% (57745 vs 45188). Single-thread performance is also firmly in the Core Ultra's corner, with PassMark single-thread at 5087 versus 3356, a 34% lead. The Core Ultra also takes Cinebench R15 multi-core (6494 vs 5392, a 17% lead) and R20 multi-core (24003 vs 22467, a 6.4% lead).

The pattern is clear: the Xeon is built for server-class throughput with massive caches and thread counts, while the Core Ultra excels at bursty, latency-sensitive desktop workloads and floating-point heavy tasks. The Xeon's Cinebench R23 multi-core win is its most important statement, while the Core Ultra's single-thread and floating-point advantages define its desktop personality.

Architecture Differences

These two chips share the Intel brand but little else. The Xeon 6520P uses the Granite Rapids architecture on a 5 nm process from Intel's own foundry, while the Core Ultra 9 285K uses Arrow Lake on a 3 nm process from TSMC. The process node difference alone explains much of the single-thread gap, as the smaller node allows higher clock speeds at lower power.

The core counts are identical at 24, but the thread counts differ drastically. The Xeon supports 48 threads via Hyper-Threading, while the Core Ultra 9 285K is limited to 24 threads. That thread advantage, combined with a 144 MB shared L3 cache versus only 36 MB on the Core Ultra, gives the Xeon its multi-core edge in scalable workloads.

Clock speeds tell the opposite story. The Core Ultra 9 285K boosts to 5.70 GHz with a 3.70 GHz base, while the Xeon 6520P manages only 4.00 GHz boost and 2.40 GHz base. That 1.70 GHz boost advantage is why the Core Ultra wins single-thread tests so decisively.

Memory architecture is another major divergence. The Xeon uses eight-channel DDR5 with a 409.6 GB/s memory bandwidth, while the Core Ultra uses dual-channel DDR5 at 102.4 GB/s. The Xeon has four times the memory bandwidth, which is critical for server workloads that stream large datasets. Both support DDR5 and ECC memory, but the Xeon's memory subsystem is built for capacity and throughput.

PCIe lanes also differ substantially. The Xeon offers 88 Gen 5 lanes from the CPU, while the Core Ultra has 20 Gen 5 lanes. The Xeon is clearly designed for systems with many GPUs, NVMe drives, and network cards. The Core Ultra relies on its integrated Arc Xe-LPG Graphics with 64 execution units, while the Xeon has no integrated graphics at all.

The physical packages reflect their different purposes. The Xeon has a 598 mm² die and runs at 210 W TDP, while the Core Ultra has a 243 mm² die with 17,800 million transistors and a 125 W TDP. The Xeon's larger die and higher power budget are the price of server-class cache and memory bandwidth. The Core Ultra is unlocked for overclocking, while the Xeon is not.

Head-to-Head Benchmarks

The single most striking result in the database is Cinebench R23 single-core, where the Xeon wins by 217.7% (7552 vs 2377). That is an enormous anomaly, and it suggests the Core Ultra's R23 single-core score is artificially low relative to its other single-thread results. The Xeon also wins Cinebench R15 single-core by 112% (761 vs 359), which reinforces that this is a test-specific quirk rather than a real architectural superiority.

In Cinebench R23 multi-core, the Xeon wins by 25.8% (53495 vs 42522), which is the most reliable indicator of sustained rendering performance. The Xeon's 48 threads and 144 MB L3 cache simply overpower the Core Ultra's 24 threads and 36 MB cache in this workload.

The Core Ultra's best win is PassMark floating-point math, where it beats the Xeon by 27.4% (224324 vs 162862). This is a large margin and points to the Core Ultra's newer, higher-clocked cores being better at vectorized math. The Core Ultra also wins PassMark single-thread by 34% (5087 vs 3356), which is the more typical single-thread comparison.

Data encryption goes to the Core Ultra by 21.7% (57745 vs 45188), likely due to faster per-core cryptographic instructions. The Xeon hits back in data compression by 6.5% (841518 vs 790052), a workload that benefits from large caches and high memory bandwidth.

Physics simulation favors the Xeon heavily at 83.1% (7209 vs 3938), and integer math favors the Xeon by 24.3% (214288 vs 172379). Extended instructions go slightly to the Xeon at 3.7% (64557 vs 62277), while random string sorting is nearly tied with the Xeon edging ahead by 0.9% (95736 vs 94927).

Prime number finding goes to the Core Ultra by a slim 2.8% (541 vs 526), and the PassMark multi-thread overall goes to the Core Ultra by 6.4% (67260 vs 62936). The Cinebench R20 multi-core also goes to the Core Ultra by 6.4% (24003 vs 22467), as does R20 single-core by 6.4% (3388 vs 3171).

The data shows a split personality. The Xeon dominates in cache-sensitive and thread-scaled workloads, while the Core Ultra wins in single-thread and floating-point tasks. The R23 single-core result for the Core Ultra appears to be an outlier, as its other single-thread scores are competitive or better.

FAQ

Q: Which CPU is faster in multi-threaded rendering workloads?

A: The Xeon 6520P is significantly faster in Cinebench R23 multi-core, scoring 53495 versus 42522 for the Core Ultra 9 285K, a 25.8% advantage. However, the Core Ultra wins Cinebench R15 and R20 multi-core by 17% and 6.4% respectively, so the result depends on the specific benchmark.

Q: Is the Core Ultra 9 285K better for single-threaded tasks?

A: Yes, in most tests. PassMark single-thread shows the Core Ultra ahead by 34% (5087 vs 3356), and Cinebench R20 single-core shows it ahead by 6.4% (3388 vs 3171). The exception is Cinebench R23 single-core, where the Xeon shows a 217.7% lead, which appears to be an anomaly in the data.

Q: Which CPU has more memory bandwidth?

A: The Xeon 6520P has four times the memory bandwidth of the Core Ultra 9 285K. The Xeon supports eight-channel DDR5 at 409.6 GB/s, while the Core Ultra uses dual-channel DDR5 at 102.4 GB/s.

Q: Do both CPUs support ECC memory?

A: Yes, both the Xeon 6520P and the Core Ultra 9 285K support ECC memory. This makes the Core Ultra suitable for entry-level workstation builds, though its dual-channel memory bus limits total bandwidth compared to the Xeon.

Q: Which CPU has more PCIe lanes for expansion?

A: The Xeon 6520P has 88 Gen 5 lanes from the CPU, while the Core Ultra 9 285K has only 20 Gen 5 lanes. The Xeon is designed for systems with many add-in cards, while the Core Ultra is suited for a single GPU and a few NVMe drives.

Q: What is the difference in power consumption?

A: The Xeon 6520P has a 210 W TDP, while the Core Ultra 9 285K has a 125 W TDP. The Xeon uses significantly more power, which is expected for a server processor with larger caches and memory bandwidth.

The Verdict

Choose the Intel Xeon 6520P if your workloads are cache-hungry, thread-scaled, or memory-bandwidth intensive. The data shows it wins in Cinebench R23 multi-core by 25.8%, integer math by 24.3%, physics by 83.1%, and data compression by 6.5%. Its 48 threads, 144 MB L3 cache, and 409.6 GB/s memory bandwidth make it the right tool for rendering, scientific computing, and heavy server workloads. The 210 W TDP and 88 PCIe lanes confirm its server-class positioning.

Choose the Intel Core Ultra 9 285K if you need a desktop processor with strong single-thread performance, floating-point capability, and encryption speed. The data shows it wins PassMark single-thread by 34%, floating-point math by 27.4%, encryption by 21.7%, and overall PassMark multi-thread by 6.4%. Its 5.70 GHz boost clock, 3 nm process, and 125 W TDP make it far more practical for a desktop build, and the integrated graphics eliminate the need for a separate GPU in basic systems.

The Xeon 6520P sits in the 96th percentile of all CPUs, as does the Core Ultra 9 285K, so both are top-tier parts. The Xeon's average benchmark score is 93786, while the Core Ultra's is 83807, a difference of about 11.9%. That average favors the Xeon, but the Core Ultra's single-thread and floating-point wins make it the better general-purpose desktop choice. The Xeon is a specialized tool for servers, while the Core Ultra is a versatile desktop processor with unusual ECC memory support for its class.

Specification Differences

| Specification | Intel Xeon 6520P | Intel Core Ultra 9 285K |

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

| Cores | 24 | 24 |

| Threads | 48 | 24 |

| Base Clock | 2.40 GHz | 3.70 GHz |

| Boost Clock | 4.00 GHz | 5.70 GHz |

| TDP | 210 W | 125 W |

| Socket | Intel Socket 4710 | Intel Socket 1851 |

| Architecture | Granite Rapids | Arrow Lake |

| Process Node | 5 nm (Intel) | 3 nm (TSMC) |

| Die Size | 598 mm² | 243 mm² |

| Transistors | Not disclosed | 17,800 million |

| L1 Cache | 112 KB per core | 192 KB per core |

| L2 Cache | 2 MB per core | 3 MB per core |

| L3 Cache | 144 MB shared | 36 MB shared |

| Memory Bus | Eight-channel | Dual-channel |

| Memory Bandwidth | 409.6 GB/s | 102.4 GB/s |

| PCIe | Gen 5, 88 lanes | Gen 5, 20 lanes |

| Integrated Graphics | N/A | Arc Xe-LPG Graphics 64EU |

| Multiplier Unlocked | No | Yes |

| Launch MSRP | $1295 | $589 |

| Release Date | 2025-02-23 | 2024-10-23 |