AMD EPYC 7663 vs AMD EPYC 9455P Comparison

The AMD EPYC 9455P is the clear winner in this comparison, taking 17 of 17 recorded benchmark wins against the AMD EPYC 7663. The data shows a generational leap that is visible across every workload category, from single-threaded tasks to heavily parallel rendering. The EPYC 7663 retains its relevance only as a legacy platform with a different memory and PCIe generation, but in raw performance, the 9455P dominates.

Where Each One Wins

The AMD EPYC 9455P wins every single benchmark in the database. There is no workload category where the EPYC 7663 posts a higher score. The 9455P leads in all Cinebench tests, both multi-core and single-core, and in all PassMark tests, including data compression, encryption, extended instructions, prime number finding, floating point math, integer math, multithreading, physics, random string sorting, and single-threaded performance.

For single-threaded workloads, the 9455P is exceptionally strong. Its Cinebench R23 single-core score of 14005 versus 9850 for the 7663 represents a 42.2% advantage. This difference is driven by the much higher boost clock of 4.40 GHz versus 3.50 GHz, combined with the newer Zen 5 architecture that delivers more instructions per clock. The PassMark single-thread score of 3745 versus 2606 shows a 43.7% gap, confirming that the 9455P is not just a multi-core monster but also a leader in lightly threaded applications.

For multi-threaded and server workloads, the 9455P again takes the lead, but the story is more nuanced. The 7663 has more cores (56 versus 48) and more threads (112 versus 96), so its multi-core deficit comes entirely from architectural efficiency and clock speed. The Cinebench R23 multi-core score of 99206 for the 9455P versus 69773 for the 7663 is a 42.2% margin. The 9455P achieves this despite having 8 fewer cores, which indicates that each Zen 5 core is far more capable than each Zen 3 core.

The largest single win for the 9455P comes in PassMark physics, where it scores 17315 versus 8020, a 115.9% delta. This test is sensitive to clock speed and architecture, and the combination of a 4.40 GHz boost and Zen 5 gives the 9455P a massive advantage. The smallest win is in data encryption, where the 9455P scores 115403 versus 111725, a 3.3% margin. This suggests the 7663’s larger core count helps it stay competitive in encryption workloads that scale well with core count.

Architecture Differences

The AMD EPYC 9455P is built on Zen 5 architecture with the Turin codename, part of the EPYC 9005 series. It uses a 4 nm process node from TSMC, with 66,520 million transistors across 8 dies, each die measuring 70.6 mm². The EPYC 7663 is built on Zen 3 architecture with the Milan codename, part of the EPYC 7003 series. It uses a 7 nm process node, also from TSMC, with 33,200 million transistors across 8 dies, each die measuring 81 mm².

The cache hierarchy differs significantly. The 9455P has 80 KB of L1 cache per core, 1 MB of L2 cache per core, and 256 MB of shared L3 cache. The 7663 has 64 KB of L1 cache per core, 512 KB of L2 cache per core, and also 256 MB of shared L3 cache. Total L3 capacity is identical, but the per-core L1 and L2 caches on the 9455P are larger, which benefits single-threaded and lightly threaded workloads.

Memory support is a major divergence. The 9455P supports DDR5 memory with a twelve-channel memory bus, providing 576.0 GB/s of bandwidth. The 7663 supports DDR4 memory with an eight-channel memory bus, providing 204.8 GB/s of bandwidth. This is a 2.8x difference in theoretical memory bandwidth, which heavily impacts memory-intensive workloads such as data compression and floating point math.

PCIe generation also differs. The 9455P offers PCIe Gen 5 with 128 lanes (CPU only), while the 7663 offers PCIe Gen 4 with 128 lanes (CPU only). The newer PCIe Gen 5 standard doubles the per-lane bandwidth, which matters for storage and accelerator connectivity. Both processors support ECC memory, and neither has integrated graphics.

The sockets are not compatible. The 9455P uses AMD Socket SP5, while the 7663 uses AMD Socket SP3. This means a platform upgrade is required to move from the 7663 to the 9455P, and the memory controller change from DDR4 to DDR5 also necessitates new memory.

Head-to-Head Benchmarks

The Cinebench suite shows a consistent 42.2% advantage for the 9455P across all tests. In Cinebench R15 multi-core, the 9455P scores 9999 versus 7032. In R15 single-core, it scores 1411 versus 992. In R20 multi-core, 41666 versus 29304. In R20 single-core, 5882 versus 4137. In R23 multi-core, 99206 versus 69773. In R23 single-core, 14005 versus 9850. The uniformity of this 42.2% delta across all Cinebench tests indicates that the 9455P’s advantage comes from a combination of higher clock speeds and better instructions per clock, rather than from any workload-specific optimization.

The PassMark suite shows more variance. Data compression scores 1928897 for the 9455P versus 1447020 for the 7663, a 33.3% delta. This test benefits from the larger L2 cache and higher memory bandwidth of the 9455P, but the gap is smaller than the Cinebench delta, suggesting that the 7663’s extra cores help close the distance in compression workloads.

Data encryption is the closest benchmark, with 115403 versus 111725, a 3.3% delta. This test is typically bound by the AES-NI instruction throughput, and both processors support hardware encryption acceleration. The 9455P still wins, but the 7663’s 56 cores keep it within striking distance.

Extended instructions show the second-largest delta at 86.5%, with 137485 versus 73719. This test measures AVX-512 and similar instruction throughput, where Zen 5’s wider vector units provide a substantial advantage over Zen 3. Prime number finding shows a 63.8% delta (1107 versus 676), and floating point math shows a 42.2% delta (357783 versus 251535), matching the Cinebench pattern.

Integer math shows a 29.5% delta (606239 versus 468096), which is smaller than the floating point delta, indicating that the 9455P’s advantage is more pronounced in floating point-heavy workloads. Multithreaded PassMark shows a 42.4% delta (116927 versus 82087), and physics shows the largest delta at 115.9% (17315 versus 8020). Random string sorting shows a 31.6% delta (242701 versus 184367).

Single-threaded PassMark scores are 3745 versus 2606, a 43.7% delta, which is the largest single-threaded advantage in the data. This aligns with the Cinebench single-core results and confirms the 9455P’s dominance in lightly threaded scenarios.

Specification Differences

| Specification | AMD EPYC 9455P | AMD EPYC 7663 |

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

| Series | EPYC 9005 series | EPYC 7003 series |

| Cores | 48 | 56 |

| Threads | 96 | 112 |

| Base Clock | 3.15 GHz | 2.00 GHz |

| Boost Clock | 4.40 GHz | 3.50 GHz |

| TDP | 300 W | 240 W |

| Socket | AMD Socket SP5 | AMD Socket SP3 |

| Architecture | Zen 5 | Zen 3 |

| Codename | Turin | Milan |

| Process Node | 4 nm | 7 nm |

| Transistors | 66,520 million | 33,200 million |

| Die Size | 8x 70.6 mm² | 8x 81 mm² |

| L1 Cache | 80 KB (per core) | 64 KB (per core) |

| L2 Cache | 1 MB (per core) | 512 KB (per core) |

| L3 Cache | 256 MB (shared) | 256 MB (shared) |

| Memory Support | DDR5 | DDR4 |

| Memory Bus | Twelve-channel | Eight-channel |

| Memory Bandwidth | 576.0 GB/s | 204.8 GB/s |

| PCIe | Gen 5, 128 Lanes (CPU only) | Gen 4, 128 Lanes (CPU only) |

| Release Date | 2024-10-09 | 2021-03-14 |

| Launch MSRP | $4819 | $6366 |

The 9455P has fewer cores but a much higher base clock (3.15 GHz versus 2.00 GHz) and boost clock (4.40 GHz versus 3.50 GHz). Its TDP is higher at 300 W versus 240 W, which reflects the more power-hungry but also more capable Zen 5 cores. The 9455P also uses a smaller 4 nm process node versus 7 nm, and it has roughly double the transistor count (66,520 million versus 33,200 million).

The die size is smaller per die on the 9455P (70.6 mm² versus 81 mm²), despite having more transistors, which is a direct result of the denser 4 nm process. The 9455P also has a newer release date (2024-10-09 versus 2021-03-14), making it a significantly more recent product.

The 9455P’s launch MSRP is $4819, while the 7663’s launch MSRP is $6366. The 9455P is both faster and cheaper at launch, which is notable, but the 7663 is an older product that may have different street pricing.

FAQ

Q: Which processor is faster in single-threaded workloads?

A: The AMD EPYC 9455P wins all single-threaded benchmarks. It scores 14005 in Cinebench R23 single-core versus 9850 for the 7663, a 42.2% delta. In PassMark single-thread, it scores 3745 versus 2606, a 43.7% delta.

Q: Does the EPYC 7663 have more cores than the 9455P?

A: Yes, the 7663 has 56 cores and 112 threads, while the 9455P has 48 cores and 96 threads. Despite this, the 9455P wins every multi-core benchmark due to its higher clock speeds and newer architecture.

Q: What is the memory bandwidth difference between the two?

A: The 9455P supports DDR5 with a twelve-channel memory bus, providing 576.0 GB/s of bandwidth. The 7663 supports DDR4 with an eight-channel memory bus, providing 204.8 GB/s of bandwidth. The 9455P offers nearly three times the theoretical bandwidth.

Q: Are the two processors socket-compatible?

A: No. The 9455P uses AMD Socket SP5, while the 7663 uses AMD Socket SP3. A platform upgrade is required to switch between them, including new memory because the 9455P uses DDR5 and the 7663 uses DDR4.

Q: Which processor has the larger L3 cache?

A: Both processors have 256 MB of shared L3 cache. The difference is in L1 and L2 caches, where the 9455P has 80 KB and 1 MB per core respectively, versus 64 KB and 512 KB per core for the 7663.

Q: What is the largest benchmark win for the 9455P?

A: The largest win is in PassMark physics, where the 9455P scores 17315 versus 8020 for the 7663, a 115.9% delta. The smallest win is in data encryption, with a 3.3% delta.

The Verdict

The data is unambiguous. The AMD EPYC 9455P wins all 17 head-to-head benchmarks against the AMD EPYC 7663. Any workload that runs on the 7663 will run faster on the 9455P, with the typical advantage falling between 30% and 45%, and ranging as high as 115.9% in physics and 86.5% in extended instructions.

The 9455P is the correct choice for new server or workstation deployments that require maximum performance. Its DDR5 memory support with 576.0 GB/s of bandwidth, PCIe Gen 5 connectivity, and higher clock speeds make it suitable for both compute-heavy and memory-bound workloads. The 48 cores are fewer than the 7663’s 56 cores, but they deliver more performance per core, so the total throughput is higher.

The 7663 remains a functional processor for existing SP3 platforms with DDR4 memory. It has more cores, which can be beneficial in highly parallel workloads that are not memory-bound, such as certain encryption tasks. Its lower TDP of 240 W versus 300 W also makes it easier to cool. However, its performance is consistently lower across every benchmark in the database, and its older Zen 3 architecture and slower memory subsystem place it at a significant disadvantage.

For users building a new system, the 9455P is the clear recommendation based on the recorded data. For users with an existing SP3 platform who cannot justify a full platform upgrade, the 7663 still provides 56 cores of Zen 3 performance, but the benchmark data shows it will trail the 9455P by at least 3.3% and often by more than 40% in the same workloads.