Intel Core i9-9900X vs Intel Xeon E-2378G Comparison

The Intel Core i9-9900X and the Intel Xeon E-2378G are both 14 nm Intel parts, but they target entirely different market segments. The data shows a clear, if narrow, performance victory for the older Core i9-9900X across every benchmark recorded, yet the Xeon E-2378G counters with a much lower TDP, newer platform features, and ECC memory support. This comparison is not about a knockout but about which tool fits which job, with the benchmark results revealing a consistent pattern of small but real performance deltas.

Head-to-Head Benchmarks

The Core i9-9900X wins all six head-to-head benchmark comparisons, though by a remarkably consistent margin. In Cinebench R15 multicore, the i9-9900X scores 1851 against the Xeon E-2378G's 1811, a 2.2% lead. The single-core R15 test shows a similar story: 261 for the i9-9900X versus 255 for the Xeon, a 2.4% advantage. This pattern holds through every Cinebench iteration. In R20 multicore, the i9-9900X posts 7713 against 7549 (2.2% ahead), and in R20 single-core it scores 1088 versus 1065 (2.2% ahead). The R23 results mirror this exactly: the i9-9900X leads 18365 to 17974 in multicore and 2592 to 2537 in single-core, both by 2.2%.

The most significant observation is not the size of the win but its universality. The i9-9900X edges out the Xeon in every single test, from the older R15 workload to the more demanding R23, and in both single-threaded and multi-threaded scenarios. While the deltas are small, they are perfectly consistent, suggesting a genuine architectural advantage rather than benchmark noise. The i9-9900X also has Geekbench scores recorded—9109 multicore and 1429 single-core—which the Xeon data does not include, further extending its measured performance coverage. In terms of overall average benchmark score, the i9-9900X sits at 5301, slightly above the Xeon's 5199. Both CPUs land in the 60th percentile of all CPUs, placing them in the same general performance tier. Notably, the i9-9900X's nearest rival is the AMD Ryzen Threadripper 1920X with an average score of 5306, a delta of just -0.1%, meaning the i9-9900X is effectively tied with that high-end desktop part. The Xeon E-2378G, meanwhile, is most closely matched by the Intel Core i5-13400T, which scores 5210, a -0.2% delta.

FAQ

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

A: The Intel Core i9-9900X wins in every recorded multi-core test. It leads by 2.2% in Cinebench R15 (1851 vs 1811), R20 (7713 vs 7549), and R23 (18365 vs 17974). Its Geekbench multicore score is 9109.

Q: Is the Xeon E-2378G better for single-threaded tasks?

A: No. Despite its higher boost clock of 5.10 GHz, the Xeon E-2378G loses all three single-core Cinebench tests to the i9-9900X. The i9-9900X scores 261 vs 255 in R15, 1088 vs 1065 in R20, and 2592 vs 2537 in R23, with deltas of 2.2% to 2.4%.

Q: Does the Xeon E-2378G support ECC memory?

A: Yes. The Xeon E-2378G has ECC memory support, while the Intel Core i9-9900X does not. This is a critical differentiator for server and workstation reliability.

Q: What are the power consumption differences?

A: The Xeon E-2378G has a TDP of 80 watts, while the Core i9-9900X has a TDP of 165 watts. The Xeon is rated for less than half the thermal design power of the i9-9900X.

Q: Which processor has a higher boost clock?

A: The Xeon E-2378G has a boost clock of 5.10 GHz, which is higher than the Core i9-9900X's 4.50 GHz. However, this higher clock does not translate into a benchmark win in the recorded tests.

Q: How many PCIe lanes does each CPU provide?

A: The Core i9-9900X provides 44 PCIe Gen 3 lanes, while the Xeon E-2378G provides 20 PCIe Gen 4 lanes. The i9-9900X has more lanes, but the Xeon supports a newer PCIe generation.

Where Each One Wins

The Core i9-9900X wins exclusively on raw benchmark performance. It outperforms the Xeon E-2378G in all six head-to-head Cinebench tests, covering both single-core and multi-core scenarios. With 10 cores and 20 threads against the Xeon's 8 cores and 16 threads, the i9-9900X leverages its additional parallelism effectively, even with a lower boost clock. Its win in the single-core tests, despite the Xeon's 5.10 GHz boost advantage, suggests the i9-9900X's architecture delivers more instructions per clock in these workloads. For anyone seeking maximum Cinebench output, the i9-9900X is the clear choice.

The Xeon E-2378G wins on platform and operational characteristics. Its 80-watt TDP makes it far more power-efficient on paper than the 165-watt i9-9900X. It is an active, current product, whereas the i9-9900X is end-of-life. The Xeon supports ECC memory, which is essential for data integrity in server environments, and it includes integrated UHD Graphics P750, a feature the i9-9900X lacks entirely. It also uses the Intel Socket 1200 platform with PCIe Gen 4 support, whereas the i9-9900X uses the older Intel Socket 2066 with PCIe Gen 3. The Xeon's smaller die size of 276 mm², compared to the i9-9900X's unspecified die, further suggests a more modern and efficient design.

Specification Differences

The two processors differ in nearly every fundamental specification. The Core i9-9900X has 10 cores and 20 threads, while the Xeon E-2378G has 8 cores and 16 threads. The i9-9900X has a higher base clock of 3.50 GHz versus the Xeon's 2.80 GHz, but the Xeon has a higher boost clock of 5.10 GHz versus the i9-9900X's 4.50 GHz. The TDP gap is substantial: 165 watts for the i9-9900X versus 80 watts for the Xeon.

The memory subsystem differs significantly. The i9-9900X supports quad-channel DDR4 with a memory bandwidth of 85.3 GB/s, while the Xeon E-2378G supports dual-channel DDR4 with 51.2 GB/s. The i9-9900X has no ECC support, while the Xeon does. The i9-9900X offers 44 PCIe Gen 3 lanes, while the Xeon offers 20 PCIe Gen 4 lanes. The i9-9900X has no integrated graphics; the Xeon includes UHD Graphics P750. The i9-9900X has an unlocked multiplier, while the Xeon's is locked. The i9-9900X uses Intel Socket 2066 and the Xeon uses Intel Socket 1200.

Architecture Differences

The architectural split is between two distinct Intel designs. The Core i9-9900X is based on the Skylake-X architecture, part of the Core i9 X-Series 9th Gen family, built on a 14 nm process. It features 64 KB of L1 cache per core and 1 MB of L2 cache per core, with a shared 19.25 MB L3 cache. The Xeon E-2378G, in contrast, is based on the Rocket Lake-E architecture, part of the Xeon E-2300 series, also on a 14 nm process. It has 80 KB of L1 cache per core and 512 KB of L2 cache per core, with a shared 16 MB L3 cache.

The cache hierarchy reveals different design priorities. The i9-9900X has a larger L2 cache per core and a larger total L3 cache, which benefits its 10-core configuration. The Xeon has a larger L1 cache per core but a smaller L2 and L3, optimized for its 8-core layout. The i9-9900X was released in October 2018 and is end-of-life, while the Xeon E-2378G was released in September 2021 and remains active. The Xeon's die size is 276 mm², while the i9-9900X's is not listed. The i9-9900X supports quad-channel memory, while the Xeon supports dual-channel, directly impacting the measured memory bandwidth difference.

The Verdict

The benchmark data is unambiguous: the Intel Core i9-9900X is the faster processor. It wins every single recorded benchmark against the Xeon E-2378G, from Cinebench R15 to R23, in both single-core and multi-core tests. Its 2.2% to 2.4% leads are consistent and reproducible across all workloads. It also holds a Geekbench multicore score of 9109, which is not matched by any Xeon benchmark in the data. For users whose primary metric is raw compute performance, the i9-9900X is the superior choice, even though it is an older, end-of-life product with a higher TDP.

The Intel Xeon E-2378G is the right pick for a different set of priorities. Its 80-watt TDP makes it far more energy-efficient on paper than the 165-watt i9-9900X. It is an active product with ECC memory support, making it suitable for server environments where data integrity is critical. It includes integrated graphics, which the i9-9900X lacks, and uses the newer PCIe Gen 4 interface. Its higher boost clock of 5.10 GHz does not translate to a benchmark win, but its platform features and power profile are compelling for workstation and server deployments. In short, the i9-9900X wins on performance; the Xeon E-2378G wins on efficiency, reliability, and platform modernity.