Intel Core i9-9900X vs Intel Xeon W-2155 Comparison

The Verdict

The Intel Core i9-9900X is the clear performance winner in every recorded benchmark, taking all six head-to-head tests. It leads by margins between 4.7% and 4.8% across both single-core and multi-core workloads. If your priority is raw compute throughput and you are building a desktop system, the i9-9900X is the straightforward choice.

The Intel Xeon W-2155 is not without its own appeal. It carries ECC memory support, a feature entirely absent from the i9-9900X, along with more PCIe lanes (48 versus 44). These features point toward workstation reliability and expandability. The Xeon also draws less power, with a 140 W TDP compared to the i9-9900X's 165 W. For a system that must run unattended with error-correcting memory, the Xeon W-2155 is the practical pick despite its slightly lower benchmark scores.

The data also shows a launch MSRP of $989 for the i9-9900X and $1440 for the Xeon W-2155. Both processors are end-of-life. The choice here is simple: the i9-9900X for speed, the Xeon W-2155 for workstation-grade features.

Architecture Differences

Both processors share the same fundamental Skylake architecture, but they diverge in their specific implementations. The i9-9900X is built on the Skylake-X codename, while the Xeon W-2155 uses the Skylake-W variant. Both are fabricated on Intel's 14 nm process. The i9-9900X belongs to the Core i9 X-Series 9th Gen family, whereas the Xeon W-2155 is part of the Xeon W Skylake-W lineup.

The core configuration is identical: 10 cores and 20 threads on each chip. Base clocks differ slightly, with the i9-9900X starting at 3.50 GHz and the Xeon W-2155 at 3.30 GHz. Boost clocks are the same at 4.50 GHz. Both processors sit on the Intel Socket 2066 platform.

Cache layouts show a notable divergence. The L1 and L2 caches match at 64 KB per core and 1 MB per core respectively. The L3 cache, however, is significantly larger on the i9-9900X at 19.25 MB shared, compared to 13.75 MB shared on the Xeon W-2155. That 5.5 MB difference in last-level cache likely contributes to the i9-9900X's benchmark advantage.

Memory support is similar on paper: both use DDR4 with a quad-channel memory bus and identical 85.3 GB/s memory bandwidth. The critical difference is ECC support, which the Xeon W-2155 includes and the i9-9900X does not. PCIe connectivity also differs, with the Xeon offering 48 Gen 3 lanes versus 44 on the i9-9900X.

The multiplier is unlocked on the i9-9900X, allowing overclocking. The Xeon W-2155 has a locked multiplier, restricting frequency adjustments. The die size is listed for the Xeon at 484 mm², while no die size is recorded for the i9-9900X. Neither chip has integrated graphics.

Head-to-Head Benchmarks

The i9-9900X wins every single recorded comparison. In Cinebench R15 multi-core, it scores 1851 against 1767 for the Xeon W-2155, a 4.8% advantage. The single-core R15 test shows the same 4.8% margin, with scores of 261 and 249 respectively.

Cinebench R20 tells the same story. The i9-9900X posts 7713 in multi-core versus 7365, a 4.7% lead. Single-core R20 results are 1088 against 1039, again a 4.7% gap. The pattern holds in newer workloads too.

Cinebench R23 multi-core scores 18365 for the i9-9900X and 17538 for the Xeon W-2155, a 4.7% difference. Single-core R23 follows with 2592 against 2475, also 4.7% apart. The i9-9900X also has a Geekbench multi-core score of 9109 and a single-core score of 1429, while no Geekbench results are recorded for the Xeon W-2155.

The consistent margin across all tests suggests the performance gap is structural rather than workload-specific. The larger L3 cache and higher base clock on the i9-9900X likely explain the uniform advantage. The Xeon never comes within 4% of the i9-9900X in any test, and the win count stands at 6-0.

FAQ

Q: Which processor has better multi-core performance?

A: The Intel Core i9-9900X is ahead in every multi-core test. It leads by 4.8% in Cinebench R15 multi-core (1851 vs 1767), 4.7% in R20 multi-core (7713 vs 7365), and 4.7% in R23 multi-core (18365 vs 17538).

Q: Is there any difference in single-core speed?

A: Yes, the i9-9900X wins all three single-core Cinebench tests by 4.7% to 4.8%. Scores are 261 vs 249 in R15, 1088 vs 1039 in R20, and 2592 vs 2475 in R23.

Q: Does the Xeon W-2155 support ECC memory?

A: Yes, ECC memory support is listed for the Xeon W-2155. The i9-9900X does not support ECC memory. This is a key differentiator for workstation reliability.

Q: Which CPU has more PCIe lanes?

A: The Xeon W-2155 provides 48 Gen 3 lanes, while the i9-9900X provides 44 Gen 3 lanes. The Xeon has a four-lane advantage for additional expansion cards.

Q: Can the Xeon W-2155 be overclocked?

A: No, the Xeon W-2155 has a locked multiplier. The i9-9900X has an unlocked multiplier, making it the overclocking option.

Q: Do these processors share the same memory bandwidth?

A: Yes, both use quad-channel DDR4 with an identical 85.3 GB/s memory bandwidth rating.

Where Each One Wins

The i9-9900X wins in raw performance across the board. Every recorded benchmark, single-core and multi-core, favors this chip. The 4.7% to 4.8% margins are consistent and repeatable across three Cinebench versions. If your work is bound by CPU throughput, whether rendering, compiling, or running heavily threaded simulations, the data points squarely at the i9-9900X. The unlocked multiplier adds another layer of performance potential for users willing to tune their systems.

The Xeon W-2155 wins on platform features. ECC memory support is the standout difference, making it the choice for data integrity in long-running compute jobs or file servers where a bit flip could corrupt results. The extra PCIe lanes, 48 versus 44, provide more headroom for multiple GPUs, NVMe storage cards, or other high-bandwidth peripherals. The lower 140 W TDP versus 165 W also means less heat output and potentially simpler cooling requirements.

The market segments reflect these priorities. The i9-9900X is classified as a desktop part, aimed at enthusiasts and content creators who want maximum performance. The Xeon W-2155 is a server and workstation part, designed for systems where stability and validation matter more than peak speed. Neither chip is current production, but the use-case split remains clear from the recorded data.

Specification Differences

Both processors share the same 10-core, 20-thread layout, 14 nm process node, and Skylake architecture family. The base clock differs, with the i9-9900X at 3.50 GHz and the Xeon W-2155 at 3.30 GHz. Boost clocks match at 4.50 GHz.

L3 cache is the largest specification gap. The i9-9900X carries 19.25 MB shared L3, while the Xeon W-2155 has 13.75 MB shared. L1 and L2 caches are identical at 64 KB per core and 1 MB per core.

TDP ratings differ, with the i9-9900X at 165 W and the Xeon W-2155 at 140 W. The Xeon has a larger die at 484 mm², while no die size is recorded for the i9-9900X.

Memory support is where the Xeon pulls ahead. Both use DDR4 with quad-channel buses and 85.3 GB/s bandwidth, but the Xeon W-2155 adds ECC support, which the i9-9900X lacks. PCIe connectivity also favors the Xeon: 48 Gen 3 lanes versus 44 on the i9-9900X.

The multiplier situation is reversed. The i9-9900X has an unlocked multiplier for overclocking, while the Xeon W-2155 is locked. The Xeon is classified as a server and workstation part, while the i9-9900X is a desktop part. Release dates differ, with the Xeon arriving earlier in 2017 and the i9-9900X following in 2018. Both are end-of-life. The part numbers are SREZ7 for the i9-9900X and SR3LR for the Xeon W-2155.