AMD EPYC 7281 vs Intel Core i9-11900KB Comparison

Head-to-Head Benchmarks

The benchmark data leaves little ambiguity in this matchup. The Intel Core i9-11900KB wins all six recorded Cinebench comparisons against the AMD EPYC 7281, though the margins are tighter than the core count disparity might suggest.

In multi-core workloads, the Intel part leads by a consistent 5.1% across every generation of the Cinebench test. The Cinebench R15 multi-core run shows 1946 for the i9-11900KB versus 1852 for the EPYC 7281. That same 5.1% gap appears in Cinebench R20 multi-core, with scores of 8112 and 7718 respectively, and in Cinebench R23 multi-core, where the Intel chip scores 19316 against the AMD chip's 18377. The consistency of that delta across all three test versions suggests a stable performance relationship rather than a workload-specific quirk.

Single-core results tell a similar story. The i9-11900KB scores 274 in Cinebench R15 single-core, 1145 in R20 single-core, and 2727 in R23 single-core. The EPYC 7281 trails at 261, 1089, and 2594 respectively. The single-core deltas range from 5.0% to 5.1%, mirroring the multi-core margins. This is notable because the EPYC 7281 has twice as many physical cores (16 versus 8), yet the Intel chip still manages to match or exceed it in heavily threaded tests.

The average benchmark score reinforces the picture. The i9-11900KB posts an average of 5587 across the database, while the EPYC 7281 averages 5315. The Intel part's nearest rivals in the database include the Intel Atom x7433RE (5601, a 0.2% gap) and the Intel Core i7-12700T (5606, a 0.3% gap), placing it in a crowded performance band. The EPYC 7281 sits near the Intel Core i9-10900KF (5316, a 0% delta) and the AMD Ryzen Threadripper 1920X (5306, a 0.2% delta). Both processors occupy roughly the 60th percentile versus all CPUs, with the i9-11900KB at 61 and the EPYC 7281 at 60.

The key takeaway from the head-to-head data is that the Intel chip wins everywhere, but by a narrow margin. A 5.1% multi-core lead is meaningful but not transformative, especially when the EPYC part brings double the core count to the table. The single-core advantage is equally modest, which suggests the i9-11900KB's higher clock speeds do not translate into a dominant lead.

FAQ

Q: Which processor is faster in multi-core workloads?

A: The Intel Core i9-11900KB wins all three multi-core Cinebench tests. It leads by 5.1% in R15 (1946 versus 1852), R20 (8112 versus 7718), and R23 (19316 versus 18377).

Q: Does the EPYC 7281 win any benchmark categories?

A: No. The recorded data shows the EPYC 7281 with zero wins across all six head-to-head comparisons. The Intel part takes both single-core and multi-core tests in every Cinebench version.

Q: How do their average scores compare?

A: The i9-11900KB has an average benchmark score of 5587, while the EPYC 7281 sits at 5315. The Intel chip also ranks slightly higher in percentile versus all CPUs, at 61 compared to 60 for the AMD part.

Q: What is the core and thread difference?

A: The EPYC 7281 has 16 cores and 32 threads, exactly double the 8 cores and 16 threads of the i9-11900KB. Despite this, the Intel chip still achieves higher benchmark scores.

Q: How do clock speeds differ?

A: The i9-11900KB has a base clock of 3.30 GHz and a boost clock of 5.30 GHz. The EPYC 7281 runs at 2.10 GHz base and 2.70 GHz boost. The Intel part's boost clock is nearly double the AMD chip's.

Q: Which processor has better memory bandwidth?

A: The EPYC 7281 supports eight-channel memory with a bandwidth of 170.6 GB/s, while the i9-11900KB uses dual-channel memory at 51.2 GB/s. The AMD part offers more than three times the theoretical bandwidth.

Architecture Differences

The two processors come from fundamentally different design philosophies. The i9-11900KB uses Intel's Tiger Lake architecture, built on a 10 nm process at Intel's own foundry. The EPYC 7281 uses AMD's Zen architecture, codenamed Naples, fabricated on a 14 nm process at GlobalFoundries.

The cache layouts differ substantially. The Intel chip allocates 80 KB of L1 per core and 1.25 MB of L2 per core, with 24 MB of shared L3. The AMD chip provides 96 KB of L1 per core and 512 KB of L2 per core, with 32 MB of shared L3. The AMD part has more total L3 cache, but the Intel part has more than double the L2 cache per core, which can benefit workloads with high per-thread locality.

The transistor counts and die sizes reflect the process node difference. The EPYC 7281 packs 4,800 million transistors into a 213 mm² die, while the i9-11900KB uses a 190 mm² die. The Intel chip achieves competitive performance on a smaller die with a more advanced process node.

Memory architecture is another major divergence. The EPYC 7281 supports eight-channel DDR4 memory with a bandwidth of 170.6 GB/s, a server-class configuration. The i9-11900KB uses dual-channel DDR4 at 51.2 GB/s. The EPYC also supports ECC memory, while the Intel part does not.

The EPYC 7281 uses PCIe Gen 3, while the i9-11900KB provides PCIe Gen 4 with 20 lanes from the CPU. The Intel chip also includes integrated UHD Graphics 750, whereas the EPYC 7281 has no integrated graphics at all. The Intel part's socket is BGA 1787, indicating a mobile-oriented package, while the EPYC uses AMD Socket SP3 for server platforms.

Specification Differences

The core and thread counts are the most obvious split: the i9-11900KB offers 8 cores and 16 threads, while the EPYC 7281 doubles that to 16 cores and 32 threads.

Clock speeds favor Intel heavily. The i9-11900KB runs at 3.30 GHz base and 5.30 GHz boost. The EPYC 7281 sits at 2.10 GHz base and 2.70 GHz boost. The Intel part's boost clock is 2.6 GHz higher.

Power consumption goes the other way. The i9-11900KB has a 65 W TDP, while the EPYC 7281 draws 170 W. That is a 105 W difference in favor of the Intel chip.

Process node and foundry differ: Intel uses its own 10 nm process, while AMD relies on GlobalFoundries' 14 nm node. Die size is 190 mm² for Intel versus 213 mm² for AMD, and the AMD chip carries 4,800 million transistors compared to an unreported count for Intel.

Memory bandwidth and channels are drastically different. The EPYC 7281 provides eight-channel memory at 170.6 GB/s, while the i9-11900KB offers dual-channel at 51.2 GB/s. ECC support is present only on the AMD part.

PCIe generations differ: the i9-11900KB supports PCIe Gen 4 with 20 CPU lanes, while the EPYC 7281 is limited to PCIe Gen 3. The Intel chip includes integrated UHD Graphics 750; the EPYC has none.

Market positioning also separates them. The i9-11900KB targets the mobile segment and is end-of-life, with a launch MSRP of $539. The EPYC 7281 targets server and workstation use, remains in active production, and released on 2017-06-28. Both have unlocked multipliers.

Where Each One Wins

The i9-11900KB wins every benchmark category in the recorded data, but the nature of those wins points to different use cases. Its higher single-core scores, driven by the 5.30 GHz boost clock, make it the better choice for latency-sensitive tasks that rely on a few fast threads. The 5.0% to 5.1% single-core lead over the EPYC 7281 is consistent across all three Cinebench versions.

Multi-core performance also favors the Intel chip, despite the EPYC's 16 cores. The 5.1% lead in every multi-core test suggests the i9-11900KB's higher clock speeds and per-core efficiency compensate for its core deficit. For workloads that do not scale perfectly across many threads, the Intel part will likely deliver better results.

The EPYC 7281 wins on platform capabilities rather than raw benchmark scores. Its eight-channel memory with 170.6 GB/s bandwidth and ECC support make it suitable for memory-intensive server workloads where data integrity and bandwidth matter more than single-thread speed. The 32 threads provide headroom for heavily parallel tasks that can use all available cores, even if the benchmark suite does not reflect that advantage.

The i9-11900KB also wins on power efficiency. Its 65 W TDP versus the EPYC's 170 W means it delivers higher benchmark scores while consuming far less power. For compact systems or deployments where thermal and power budgets are tight, that is a significant practical advantage.

The Verdict

The data points to a clear performance winner: the Intel Core i9-11900KB takes every recorded benchmark, with a 5.1% lead across multi-core tests and a 5.0% to 5.1% lead in single-core tests. It achieves this with 8 cores and 16 threads against the EPYC 7281's 16 cores and 32 threads, at a 65 W TDP versus 170 W, and in a mobile package with integrated graphics.

The EPYC 7281 is not without reason to exist. Its eight-channel memory subsystem, ECC support, and 32 threads target server workloads that the benchmark suite does not fully capture. The 170.6 GB/s memory bandwidth is more than three times the Intel chip's 51.2 GB/s, which matters for memory-bound enterprise applications.

For most users comparing these two CPUs, the i9-11900KB is the better buy based on the recorded data. It is faster in every tested workload, uses less power, and includes features like PCIe Gen 4 and integrated graphics. The EPYC 7281 makes sense only if the specific requirements include ECC memory, massive memory bandwidth, or a server platform with 32 threads and active production status. The i9-11900KB is end-of-life, which is a consideration for long-term availability, but on raw benchmark performance, Intel wins this matchup across the board.