AMD EPYC 9355P vs Intel Xeon 678X Comparison

Head-to-Head Benchmarks

The recorded head-to-head data shows Intel Xeon 678X taking 12 of 16 benchmark comparisons, while the AMD EPYC 9355P claims 4 wins. In Cinebench workloads, the Intel part holds a consistent edge across all three render versions. In R15 multicore, Intel scores 8444 against AMD's 8332, a 1.3% margin. The R15 single-core result is 1192 versus 1176, a 1.4% lead. R20 multicore repeats the pattern: 35185 against 34719, again 1.3%. Single-core R20 shows 4967 versus 4901, also 1.3%. R23 multicore delivers 83775 for Intel and 82666 for AMD, another 1.3% difference. These Cinebench margins are narrow, but they are consistent across every render iteration, indicating a stable advantage in threaded and lightly threaded content creation tasks.

PassMark results are far more lopsided in Intel's favor. Data compression shows Intel at 1690896 versus AMD's 1429976, a 18.2% win. Extended instructions produce the second-largest gap: 141431 against 107622, a 31.4% margin. Floating point math is the biggest Intel victory: 362070 versus 256635, a 41.1% advantage. Data encryption adds a 3.3% win (83598 vs 80961), and multithread shows 98559 against 96603, a 2% lead. Single-thread results are essentially tied: 3758 versus 3747, a 0.3% difference.

The AMD EPYC 9355P counters in four specific tests. Physics is its standout: 13515 versus Intel's 7809, a 42.2% margin. This is the single largest delta in either direction across all comparisons. Random string sorting gives AMD a 7.1% win (176697 vs 164102). Integer math shows AMD ahead by 1.7% (412067 vs 405075). Prime number finding is close: 1044 versus 1010, a 3.3% AMD advantage. The physics result is particularly notable because it dwarfs every other benchmark gap, suggesting a fundamentally different behavior in that specific workload.

Where Each One Wins

The Intel Xeon 678X dominates in compression, encryption, extended instruction sets, and floating-point math. Data compression and extended instructions are both workloads that benefit from large vector throughput and wide execution resources, and the Intel part is 18.2% and 31.4% ahead respectively. Floating point, with a 41.1% lead, is the clearest use case for the Intel chip: any scientific computing, simulation, or rendering task that relies heavily on FP32 or FP64 arithmetic will see a substantial advantage. Encryption workloads, where Intel leads by 3.3%, also favor this part, albeit more modestly.

The AMD EPYC 9355P wins in physics simulation, random string sorting, integer arithmetic, and prime number finding. The physics result, a 42.2% margin, suggests that this workload responds to AMD's architecture in a way that no other measured test does; it is likely a single-threaded or latency-sensitive computation that leverages the AMD chip's higher base clock. Random string sorting and integer math are both memory-access and branch-heavy workloads; AMD's 7.1% and 1.7% margins indicate an edge in those patterns. Prime number finding is another small win at 3.3%.

For multithreaded rendering, the Cinebench suite shows Intel marginally ahead in every case. For single-threaded tasks, the two are effectively identical, with a 0.3% difference. The practical split is that Intel wins broadly in vector and data-parallel workloads, while AMD wins in specific latency-sensitive or branch-heavy tasks. The physics test is the one outlier where AMD's advantage is massive, but it is an isolated case.

Architecture Differences

The Intel Xeon 678X uses Granite Rapids architecture on a 5 nm process from Intel, with a dual-die design totaling 2x 598 mm². It packs 48 cores and 96 threads, with a base clock of 2.40 GHz and a boost clock of 4.90 GHz. Its thermal design power is 300 W. The cache hierarchy includes 112 KB L1 per core, 2 MB L2 per core, and 192 MB shared L3. Memory support is DDR5 across an eight-channel bus, yielding 409.6 GB/s bandwidth. PCIe is Gen 5 with 128 lanes from the CPU. The chip uses Intel Socket 4710 and has an unlocked multiplier.

The AMD EPYC 9355P belongs to the EPYC 9005 series, built on Zen 5 (Turin) architecture. It uses a 4 nm TSMC process with eight chiplets, each 70.6 mm², totaling 66,520 million transistors. It has 32 cores and 64 threads, with a base clock of 3.55 GHz and a boost clock of 4.40 GHz. TDP is 280 W. L1 is 80 KB per core, L2 is 1 MB per core, and L3 is 256 MB shared. Memory support is DDR5 across a twelve-channel bus, giving 576.0 GB/s bandwidth. PCIe is Gen 5 with 128 lanes. The socket is AMD SP5, and the multiplier is locked.

The core count difference is significant: Intel has 50% more cores (48 vs 32) and 50% more threads (96 vs 64). Yet AMD has a 47.9% higher base clock (3.55 vs 2.40 GHz) and a lower boost clock (4.40 vs 4.90 GHz). AMD's L3 cache is 33% larger (256 MB vs 192 MB), and its memory bandwidth is 40.6% higher (576.0 vs 409.6 GB/s). The process node difference (4 nm vs 5 nm) and chiplet design versus monolithic dual-die are fundamental architectural splits. AMD's higher memory channels (twelve vs eight) directly explain its bandwidth advantage. Intel's higher boost clock and larger core count explain its wins in vector-heavy workloads.

The Verdict

The data indicates that the Intel Xeon 678X is the better choice for compute-heavy data-parallel workloads. Its 41.1% lead in floating point math and 31.4% lead in extended instructions are decisive. The chip also holds a consistent, if narrow, edge across all Cinebench render tests, making it the default pick for multithreaded rendering and simulation. The 18.2% advantage in data compression and 3.3% in encryption further solidify its position for server-side data processing and secure communications.

The AMD EPYC 9355P is the better option for physics-based simulation, where it leads by 42.2%, and for workloads that match its random string sorting (7.1% lead) or integer math (1.7% lead) profiles. Its higher base clock and larger L3 cache suggest an advantage in latency-sensitive, branch-heavy code. However, the AMD chip wins only 4 of 16 comparisons, and its margins are small except for physics. The Intel part wins 12 of 16, with several margins above 18%.

For a buyer optimizing for floating-point or vector throughput, the Intel Xeon 678X is clearly superior. For a buyer running physics engines or certain sorting/integer benchmarks, the AMD EPYC 9355P is the stronger pick. The two parts are nearly tied in single-threaded performance (0.3% difference), so that metric should not drive the decision. The overall average benchmark score favors Intel: 193477 versus 160358, a 20.6% gap, though this average includes all PassMark and Cinebench results. The Intel part also sits at the 99th percentile among all CPUs, while AMD is at the 98th.

FAQ

Q: Which processor wins in Cinebench R23 multicore?

A: The Intel Xeon 678X scores 83775 versus the AMD EPYC 9355P's 82666, a 1.3% margin in Intel's favor.

Q: What is the largest benchmark gap between the two?

A: The largest gap is in PassMark physics, where the AMD EPYC 9355P scores 13515 against Intel's 7809, a 42.2% lead for AMD.

Q: How do the two compare in floating point math?

A: Intel leads by 41.1%: 362070 versus AMD's 256635.

Q: What are the core and thread counts?

A: The Intel Xeon 678X has 48 cores and 96 threads. The AMD EPYC 9355P has 32 cores and 64 threads.

Q: Which chip has higher memory bandwidth?

A: The AMD EPYC 9355P has 576.0 GB/s across a twelve-channel bus, versus Intel's 409.6 GB/s across an eight-channel bus.

Q: Is the single-thread performance meaningfully different?

A: No. The Intel Xeon 678X scores 3758 and the AMD EPYC 9355P scores 3747, a 0.3% difference that is effectively a tie.