CPU Comparison

Intel Xeon 6756E and AMD EPYC 7443 represent two fundamentally different approaches to server processing, and the benchmark data reflects a dramatic split in capabilities. The Xeon 6756E is a 128-core efficiency-focused processor built on Intel’s Sierra Forest architecture, while the EPYC 7443 is a 24-core, 48-thread Zen 3 part from AMD’s Milan generation. Across the six head-to-head Cinebench tests, the EPYC 7443 wins every single one, with margins ranging from 79.8% to 79.9% in favor of the AMD chip. However, the Xeon 6756E counters with a substantial lead in raw core count and memory bandwidth, which matters for workloads that scale across many threads.

Where Each One Wins

The AMD EPYC 7443 is the clear winner in every benchmark category measured in the head-to-head comparison, which covers Cinebench R15, R20, and R23 in both single-core and multi-core variants. In multi-core tests, the EPYC 7443 scores 4,856 in Cinebench R15, 20,236 in R20, and 48,183 in R23. The Intel Xeon 6756E, despite having over five times the core count, scores just 980, 4,085, and 9,728 in the same respective tests. The delta is consistently around -79.8% for the Xeon, meaning the EPYC delivers approximately five times the performance in these threaded workloads. This suggests the EPYC’s higher clock speeds and more efficient per-core architecture dominate in applications that do not scale perfectly across hundreds of cores.

The Xeon 6756E’s advantages emerge outside the Cinebench suite, in its memory subsystem and I/O capabilities. It supports DDR5 memory with 409.6 GB/s of bandwidth, exactly double the EPYC 7443’s DDR4 bandwidth of 204.8 GB/s. It also provides PCIe Gen 5 with 88 lanes, whereas the EPYC 7443 offers PCIe Gen 4 with 128 lanes. For workloads that are memory-bandwidth bound, such as large-scale data analytics, in-memory databases, or high-performance computing simulations that stream data, the Xeon’s superior memory throughput could provide a meaningful edge, even if the Cinebench results do not reflect it. The Xeon also has a much larger L2 cache at 4 MB per module versus 512 KB per core on the EPYC, though the EPYC counters with a larger L3 cache at 128 MB shared versus 96 MB shared.

Architecture Differences

The two processors are built on entirely different blueprints. The Intel Xeon 6756E uses the Sierra Forest architecture, which is Intel’s first generation of efficiency-core (E-core) server processors, manufactured on a 5 nm process at Intel’s own foundry. It packs 128 cores and 128 threads into a 578 mm² die, with no hyperthreading, each physical core corresponds to a single thread. The base clock is 1.80 GHz with a boost of 2.60 GHz, and the TDP is rated at 225 watts. The cache hierarchy is unusual: 96 KB of L1 per core, 4 MB of L2 per module, and 96 MB of shared L3.

The AMD EPYC 7443 uses the Zen 3 architecture, codenamed Milan, built on a 7 nm process at TSMC. It has 24 cores and 48 threads, with simultaneous multithreading enabled. The base clock is 2.85 GHz and the boost clock reaches 4.00 GHz, with a TDP of 200 watts. The die is composed of four chiplets, each 81 mm², totaling 16,600 million transistors. Cache includes 64 KB of L1 per core, 512 KB of L2 per core, and 128 MB of shared L3. The EPYC uses eight-channel DDR4 memory, while the Xeon uses eight-channel DDR5.

These architectural choices explain the benchmark disparity. The EPYC’s higher clocks, 2.85 GHz base versus 1.80 GHz, and 4.00 GHz boost versus 2.60 GHz, give it a massive per-thread advantage. The Xeon’s 128 cores are clocked much lower, and with only 128 threads versus the EPYC’s 48 threads, the EPYC still manages to outpace it in multi-core Cinebench due to superior IPC and clock speed. The Xeon’s efficiency-core design targets throughput per watt, not raw performance per core.

Head-to-Head Benchmarks

The Cinebench results are one-sided, with the AMD EPYC 7443 winning all six tests. In Cinebench R15 multi-core, the EPYC scores 4,856 versus the Xeon’s 980, a 79.8% deficit for Intel. Single-core R15 shows 685 versus 138, a 79.9% gap. R20 multi-core delivers 20,236 versus 4,085, again a 79.8% difference, and single-core R20 is 2,856 versus 576, a 79.8% gap. R23 multi-core sees the EPYC at 48,183 against the Xeon’s 9,728, a 79.8% margin, and single-core R23 is 6,802 versus 1,373, a 79.8% deficit. The consistency of the delta across all tests, hovering at 79.8-79.9%, indicates a fundamental per-core performance gap rather than a workload-specific anomaly.

Looking at the broader PassMark results for the Xeon (which the EPYC lacks in the data set), the Xeon posts strong absolute numbers in certain threaded tasks: 123,443 in data compression, 30,806 in integer math, 22,451 in floating point math, and 11,445 in multithread. These scores are not directly comparable to the EPYC since no PassMark data is provided for the AMD part, but they show that the Xeon is not a weak processor overall, it simply loses to the EPYC in the specific Cinebench workloads measured head-to-head.

Specification Differences

The two processors diverge on nearly every specification that matters. The Xeon has 128 cores and 128 threads, while the EPYC has 24 cores and 48 threads. Base clocks are 1.80 GHz versus 2.85 GHz, and boost clocks are 2.60 GHz versus 4.00 GHz. TDP is 225 watts for Intel versus 200 watts for AMD. The Xeon uses a 5 nm process at Intel, while the EPYC uses 7 nm at TSMC. Memory support differs: DDR5 with 409.6 GB/s bandwidth on the Xeon, DDR4 with 204.8 GB/s on the EPYC. PCIe generations also differ: Gen 5 with 88 lanes on Intel, Gen 4 with 128 lanes on AMD. Cache configurations are distinct: L1 is 96 KB per core on Xeon versus 64 KB per core on EPYC; L2 is 4 MB per module versus 512 KB per core; L3 is 96 MB shared versus 128 MB shared. The Xeon die is 578 mm², while the EPYC uses four 81 mm² chiplets. Transistor count is only listed for the EPYC at 16,600 million. The Xeon was released in June 2024, while the EPYC launched in March 2021.

FAQ

Q: Which processor wins in multi-core Cinebench performance?

A: The AMD EPYC 7443 wins all three multi-core Cinebench tests. In R15, it scores 4,856 versus 980; in R20, 20,236 versus 4,085; and in R23, 48,183 versus 9,728. The Xeon trails by 79.8% in each case.

Q: Does the Intel Xeon 6756E have any performance advantage?

A: The Xeon does not win any of the six head-to-head benchmarks. However, it offers higher memory bandwidth at 409.6 GB/s versus 204.8 GB/s and supports DDR5, which could benefit memory-bound workloads not captured in Cinebench.

Q: What is the core and thread count difference?

A: The Xeon 6756E has 128 cores and 128 threads, while the EPYC 7443 has 24 cores and 48 threads. The Xeon has no hyperthreading, so threads equal cores, whereas the EPYC uses simultaneous multithreading to double its thread count.

Q: How do clock speeds compare?

A: The Xeon has a base clock of 1.80 GHz and a boost clock of 2.60 GHz. The EPYC has a base clock of 2.85 GHz and a boost clock of 4.00 GHz. The EPYC’s clocks are roughly 58% higher at base and 54% higher at boost.

Q: Which processor has more cache?

A: The EPYC 7443 has a larger L3 cache at 128 MB shared, compared to 96 MB shared on the Xeon. However, the Xeon has a larger L2 cache at 4 MB per module versus 512 KB per core on the EPYC, and a larger L1 at 96 KB per core versus 64 KB per core.

Q: What are the memory and PCIe differences?

A: The Xeon supports DDR5 with 409.6 GB/s bandwidth and PCIe Gen 5 with 88 lanes. The EPYC supports DDR4 with 204.8 GB/s bandwidth and PCIe Gen 4 with 128 lanes. Both use eight-channel memory buses.

The Verdict

The data is unambiguous in the Cinebench suite: the AMD EPYC 7443 outperforms the Intel Xeon 6756E by roughly 80% across every measured test, both single-core and multi-core. This is a decisive victory for AMD in these workloads. The EPYC achieves this with just 24 cores and 48 threads, compared to the Xeon’s 128 cores and 128 threads, which indicates that its higher clock speeds and Zen 3 architecture deliver vastly superior per-thread performance. The Xeon cannot compensate with core count alone, as the benchmark results show that even in multi-core tests, the EPYC’s 48 threads outpace the Xeon’s 128 threads by a factor of five.

However, the Xeon 6756E is not without rationale. Its memory bandwidth of 409.6 GB/s is double the EPYC’s 204.8 GB/s, and its DDR5 support is newer. For workloads that are heavily memory-bandwidth dependent, such as large-scale data processing, scientific computing with streaming data, or virtualization with high memory traffic, the Xeon could be the better fit, even though the Cinebench results do not reflect such scenarios. Its PCIe Gen 5 support provides faster interconnect for accelerators, though the EPYC offers more lanes at Gen 4. The Xeon also has a larger L2 cache, which may help in certain access patterns. For users who prioritize raw compute performance in CPU-bound tasks, the EPYC 7443 is the clear choice. For those who need maximum memory bandwidth and DDR5 capabilities, the Xeon 6756E has distinct advantages that benchmark scores do not capture.