Intel Xeon 6745P vs Intel Xeon 676X Comparison

Head-to-Head Benchmarks

The benchmark data paints a clear picture: the Intel Xeon 676X wins 15 of 16 head-to-head tests, with the Xeon 6745P taking only a single victory. The most dramatic margin comes in PassMark physics, where the 676X scores 8281 against the 6745P's 6144 — a 34.8% lead that suggests substantially better performance in workloads that stress physical simulation and rigid-body dynamics.

Across the Cinebench suite, the 676X is consistently 8.2% ahead. That exact delta repeats in R15 multicore (7806 vs 7214), R15 single-core (1101 vs 1018), R20 multicore (32527 vs 30062), R20 single-core (4591 vs 4244), and R23 multicore (77447 vs 71578). The uniformity of that 8.2% gap across both single-threaded and multi-threaded render tests indicates a clock-speed advantage that scales evenly rather than a core-count or cache-driven difference.

Single-thread performance tells a similar story with a wider spread. The 676X posts 4015 in PassMark single-thread, beating the 6745P's 3450 by 16.4%. That is a substantial margin for same-architecture parts and points directly to the 676X's higher boost clock.

Multi-threaded PassMark results echo the Cinebench pattern: 91115 vs 84210, again an 8.2% win. Integer math shows a 5.3% advantage (354777 vs 336926), while floating-point math favors the 676X by 6% (283570 vs 267438). Prime number finding goes to the 676X by 8.4% (738 vs 681), and random string sorting by 3.3% (137976 vs 133528).

The 676X also wins the memory-adjacent workloads. Data compression is nearly a dead heat — 1355807 vs 1352801, a 0.2% edge — while data encryption shows a 1.5% lead (67638 vs 66665). The one test the 6745P claims is PassMark extended instructions, where it scores 108326 against 105231, a 2.9% reversal. This suggests the 6745P's larger L3 cache may help with certain AVX-512 or similar extended instruction patterns, even if it cannot overcome the 676X's clock advantage elsewhere.

The average benchmark score reinforces the overall picture: the 676X averages 158540, the 6745P averages 154858, a 2.4% gap in the 676X's favor. In the broader competitive field, the 676X sits 1.1% behind the AMD EPYC 9355P and 2.1% behind the EPYC 7663, while the 6745P trails those same parts by 3.4% and 4.4% respectively.

Architecture Differences

Both processors share the same Granite Rapids architecture, built on Intel's 5 nm process with a dual-die design measuring 2x 598 mm². Both feature 32 cores and 64 threads, with identical per-core L1 (112 KB) and L2 (2 MB) caches. Both support DDR5 memory across an eight-channel bus with 409.6 GB/s of bandwidth, and both include ECC support. Integrated graphics are absent on both parts.

The first major divergence is L3 cache. The 676X has 144 MB shared, while the 6745P doubles that to 336 MB shared. That 192 MB difference is the single biggest architectural gap between the two and explains why the 6745P wins the extended instructions test — larger working sets can stay on-die without hitting memory.

Clock speeds favor the 676X. Its base clock is 2.80 GHz with a boost of 4.90 GHz, versus the 6745P's 3.10 GHz base and 4.30 GHz boost. The 676X has a higher ceiling but a lower floor; the 6745P starts faster but runs out of headroom sooner. The 676X's higher boost clock aligns with its 16.4% single-thread win, while the 6745P's higher base clock does not translate into any benchmark victory outside extended instructions.

Power and platform requirements differ meaningfully. The 676X carries a 275 W TDP and an unlocked multiplier, making it the only one of the pair that can be overclocked. The 6745P has a 300 W TDP and a locked multiplier. Both use Intel Socket 4710, so they are physically interchangeable in compatible boards, but the power-delivery and cooling demands shift.

PCIe lane counts also diverge. The 676X provides 128 Gen 5 lanes (CPU only), while the 6745P provides 88 Gen 5 lanes. For systems built around many NVMe drives, GPUs, or high-speed networking cards, that 40-lane difference is substantial.

The release timeline places the 6745P first, launching on 2025-02-23, with the 676X following on 2026-02-01. Both are listed as Active production parts. The 676X is part of the Xeon 600 (Granite Rapids-WS) generation, while the 6745P belongs to Xeon 6 (Granite Rapids-SP). The -WS suffix indicates a workstation-oriented SKU, while -SP points to scalable platform positioning.

FAQ

Q: Which chip has more L3 cache, and does it matter?

A: The Xeon 6745P has 336 MB of shared L3 cache, while the Xeon 676X has 144 MB. It matters in one measurable way: the 6745P wins PassMark extended instructions by 2.9% (108326 vs 105231). Across every other benchmark, the 676X's clock advantage overcomes the cache deficit.

Q: Can either processor be overclocked?

A: Only the Xeon 676X has an unlocked multiplier. The Xeon 6745P's multiplier is locked, so it cannot be overclocked. This is a meaningful distinction for workstation builders who want to push beyond stock boost clocks.

Q: Do both chips support the same memory configuration?

A: Yes. Both support DDR5 with an eight-channel memory bus and 409.6 GB/s of bandwidth, and both have ECC memory support. Memory capacity and speed limits are identical on paper.

Q: How much faster is the 676X in single-threaded workloads?

A: In PassMark single-thread, the 676X scores 4015 versus 3450 for the 6745P — a 16.4% advantage. Cinebench R15 and R20 single-core tests both show an 8.2% gap in the same direction.

Q: Which chip uses more power?

A: The Xeon 6745P has a 300 W TDP, while the Xeon 676X has a 275 W TDP. The 6745P draws more power despite having a lower boost clock, which suggests its larger L3 cache and higher base clock contribute to the higher rating.

Q: Are these chips interchangeable in the same motherboard?

A: Both use Intel Socket 4710, so they fit the same physical socket. However, the 676X offers 128 PCIe Gen 5 lanes versus 88 on the 6745P, and the power requirements differ, so board selection must account for those factors.

The Verdict

The data supports a straightforward choice for most buyers: the Xeon 676X is the faster processor in nearly every measurable way. It wins 15 of 16 head-to-head benchmarks, posts a 2.4% higher average score (158540 vs 154858), and offers an unlocked multiplier for additional performance tuning. Its 16.4% single-thread lead and 34.8% physics advantage are decisive for workstation workloads that depend on per-core speed.

The Xeon 6745P is not without merit, but its strengths are narrower. The 336 MB L3 cache delivers a 2.9% win in extended instructions, and its higher base clock of 3.10 GHz may benefit steady-state all-core loads that do not boost. However, that comes with a 300 W TDP — 25 W higher than the 676X — and a locked multiplier.

The 676X also carries a significantly lower launch MSRP of $2499, compared to the 6745P's $5250. The 676X gives you more performance and more PCIe lanes at less than half the launch price, which makes the 6745P hard to justify unless the larger cache is specifically relevant to your workload.

For the overwhelming majority of server and workstation applications, the Xeon 676X is the correct pick. The 6745P only makes sense if your software shows a measurable dependence on L3 capacity and cannot use the 676X's clock advantage effectively.

Specification Differences

| Specification | Intel Xeon 676X | Intel Xeon 6745P |

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

| Base Clock | 2.80 GHz | 3.10 GHz |

| Boost Clock | 4.90 GHz | 4.30 GHz |

| TDP | 275 W | 300 W |

| L3 Cache | 144 MB (shared) | 336 MB (shared) |

| PCIe | Gen 5, 128 Lanes (CPU only) | Gen 5, 88 Lanes (CPU only) |

| Multiplier | Unlocked | Locked |

| Generation | Xeon 600 (Granite Rapids-WS) | Xeon 6 (Granite Rapids-SP) |

| Release Date | 2026-02-01 | 2025-02-23 |

| Launch MSRP | $2499 | $5250 |

| Part Number | SA2CY | SRWPAQ7L9 |

Where Each One Wins

The Xeon 676X is the clear winner for single-threaded and lightly-threaded workloads. Its 16.4% PassMark single-thread advantage and 8.2% Cinebench single-core leads make it the better choice for CAD, simulation, and any application where per-core performance drives responsiveness. The 34.8% physics win further cements its position for engineering and scientific workloads that rely on physics solvers.

For multi-threaded rendering, the 676X wins by a consistent 8.2% across R15, R20, and R23. The 6745P cannot match it in Cinebench or PassMark multithread, where the 676X leads by 8.2% (91115 vs 84210). The 676X also wins integer math by 5.3% and floating-point math by 6%, making it the stronger choice for general compute tasks.

The 6745P wins only one test: PassMark extended instructions, with a 2.9% edge (108326 vs 105231). This indicates that workloads heavily utilizing AVX-512 or similar extended instruction sets — particularly those with large data sets that fit in its 336 MB L3 cache — may see a benefit. Data compression is essentially a tie at 0.2% in favor of the 676X, so the 6745P's cache advantage does not translate into meaningful wins there.

For I/O-heavy systems, the 676X's 128 PCIe Gen 5 lanes versus 88 on the 6745P provides more headroom for expansion. The 676X also offers overclocking potential with its unlocked multiplier, which the 6745P lacks.

The 6745P's higher base clock of 3.10 GHz versus 2.80 GHz on the 676X may help in sustained all-core workloads that never reach boost frequencies, but no benchmark in the data confirms this advantage materializes in practice. The 6745P's sole win remains the extended instructions test, so that is the only scenario where it should be selected over the 676X.