Intel Core i5-8279U vs Intel Xeon E3-1585L v5 Comparison

The Intel Xeon E3-1585L v5 and Intel Core i5-8279U are both 14nm quad-core parts with eight threads, yet they target fundamentally different markets. The Xeon is a server/workstation chip from the Skylake-H generation, while the i5 is a mobile processor from Coffee Lake-U. Benchmark data shows the Xeon winning all six head-to-head Cinebench comparisons, with margins consistently around 9%. However, both CPUs land at the 44th percentile among all processors, making them closely matched in overall performance, with the Xeon averaging 1989 points and the i5 averaging 1987 points.

Where Each One Wins

The Xeon E3-1585L v5 is the clear winner in every benchmark where both are measured. In Cinebench R15 multi-core, it scores 693 versus 634 for the i5-8279U, a 9.3% advantage. That pattern repeats across the entire Cinebench suite: R20 multi-core shows 2888 versus 2643 (9.3% ahead), and R23 multi-core shows 6878 versus 6294 (also 9.3% ahead). Single-core results follow the same trend, with the Xeon leading by 9% in R15 (97 vs 89), 9.4% in R20 (407 vs 372), and 9.3% in R23 (971 vs 888).

The i5-8279U does not win a single head-to-head benchmark in the provided data. Its only advantage appears outside the direct comparison: it has a Geekbench multi-core score of 3764 and single-core score of 1209, which are not measured for the Xeon. For users relying on Geekbench as a reference, the i5 demonstrates respectable absolute numbers, but it cannot outperform the Xeon in any Cinebench test. The Xeon’s higher base clock of 3.00 GHz versus 2.40 GHz likely contributes to its consistent lead, even though the i5 has a higher boost clock of 4.10 GHz versus 3.70 GHz.

In terms of market positioning, the Xeon is designed for sustained workloads in server/workstation environments, while the i5 targets mobile systems where power efficiency matters. The Xeon’s 45W TDP versus the i5’s 28W TDP suggests the former can sustain higher performance under load, which aligns with its benchmark dominance. For users prioritizing Cinebench performance, the Xeon is the only choice between these two.

Architecture Differences

Both processors are built on Intel’s 14nm process with 2,300 million transistors, but they come from different architectural families. The Xeon E3-1585L v5 uses the Skylake-H architecture with a die size of 171 mm², while the i5-8279U uses Coffee Lake-U with a smaller die at 126 mm². Both have 4 cores and 8 threads, with identical L1 cache of 64 KB per core and L2 cache of 256 KB per core. The key cache difference is L3: the Xeon has 8 MB shared, while the i5 has 6 MB shared.

Memory support diverges significantly. The Xeon supports both DDR3 and DDR4, whereas the i5 supports only DDR4. Both use dual-channel memory with the same 34.1 GB/s bandwidth. ECC memory is a major differentiator: the Xeon supports it, while the i5 does not. This makes the Xeon suitable for error-correcting workloads in servers, while the i5 is aimed at consumer mobile devices.

Integrated graphics also differ. The Xeon packs Iris Pro Graphics P580, while the i5 has Iris Pro Plus 655. Both are capable of handling display output, but the Xeon’s server-oriented graphics are less relevant for gaming or media tasks. The PCIe configuration is identical: Gen 3 with 16 lanes from the CPU. The Xeon uses the Intel BGA 1440 socket, while the i5 uses Intel BGA 1526, meaning they are not interchangeable in any system.

The Xeon has a base clock of 3.00 GHz and boost clock of 3.70 GHz, while the i5 runs at 2.40 GHz base and 4.10 GHz boost. The i5’s higher boost clock does not translate into better benchmark results, likely because the Xeon’s higher base clock and larger L3 cache compensate. The Xeon is part of the Xeon E3 generation, while the i5 belongs to the Core i5 (Coffee Lake-U) generation. The Xeon also has a launch MSRP of $445, while the i5 has a launch MSRP of $320.

Head-to-Head Benchmarks

The most decisive victory for the Xeon comes in Cinebench R20 single-core, where it scores 407 against the i5’s 372, a 9.4% margin. This is the largest percentage lead in any test. The R15 single-core test shows the smallest margin at 9%, with scores of 97 and 89. Multi-core results are tightly grouped around 9.3%: R15 shows 693 versus 634, R20 shows 2888 versus 2643, and R23 shows 6878 versus 6294.

The consistency of the ~9% delta across all six tests is notable. It suggests the Xeon’s advantage is structural rather than workload-specific. The Xeon’s 8 MB L3 cache versus 6 MB likely helps in multi-core scenarios, while its higher base clock helps single-threaded performance. The i5’s 4.10 GHz boost clock is unused in these tests, possibly because thermal or power constraints limit sustained boost on the 28W mobile part.

In the context of nearest rivals, the Xeon scores 1989 average, which is 0.1% behind the Intel Xeon E3-1285L v4 (1991) and 0.1% ahead of the AMD Ryzen 5 1500X (1992 is actually slightly higher). The i5-8279U averages 1987, which is 0.1% behind the AMD Ryzen Embedded V1756B (1986 is actually lower, so the i5 is 0.1% ahead). Both CPUs are clustered within 0.3% of each other and their rivals, indicating they sit in a very tight performance band.

The i5-8279U’s only unique benchmark data comes from Geekbench, where it scores 3764 multi-core and 1209 single-core. These numbers are not comparable to the Xeon, but they provide a reference point for the i5’s capabilities outside Cinebench. Given that the Xeon wins all six head-to-head tests, the i5’s Geekbench results do not change the overall picture: the Xeon is faster in every directly compared workload.

FAQ

Q: Which CPU has the higher base clock?

A: The Intel Xeon E3-1585L v5 has a base clock of 3.00 GHz, while the Intel Core i5-8279U has a base clock of 2.40 GHz.

Q: Does the i5-8279U support ECC memory?

A: No, ECC memory is not supported on the Intel Core i5-8279U. The Xeon E3-1585L v5 does support ECC memory.

Q: What is the L3 cache size difference between the two?

A: The Xeon E3-1585L v5 has 8 MB of shared L3 cache, while the i5-8279U has 6 MB of shared L3 cache.

Q: How much faster is the Xeon in Cinebench R23 multi-core?

A: The Xeon scores 6878, which is 9.3% higher than the i5-8279U’s 6294.

Q: Are these CPUs from the same architecture generation?

A: No, the Xeon uses Skylake-H architecture, while the i5 uses Coffee Lake-U, though both are built on a 14nm process.

Q: Which CPU has a higher boost clock?

A: The i5-8279U has a boost clock of 4.10 GHz, which is higher than the Xeon’s 3.70 GHz boost clock.

The Verdict

The data is unambiguous: the Intel Xeon E3-1585L v5 outperforms the Intel Core i5-8279U in every Cinebench test, with margins between 9% and 9.4%. For users who rely on Cinebench as a proxy for rendering or multi-threaded productivity, the Xeon is the superior choice. Its larger 8 MB L3 cache and higher base clock provide a consistent advantage, despite the i5’s higher boost clock and lower 28W TDP.

The i5-8279U is not without merit. Its lower TDP makes it better suited for mobile platforms where power draw and heat dissipation are critical. It also supports DDR4 memory and has a smaller 126 mm² die, which could indicate lower manufacturing costs. However, in raw performance, the i5 loses all six head-to-head comparisons, making it the weaker option for compute-intensive tasks.

The Xeon’s ECC memory support and server/workstation market segment make it the obvious pick for reliability-focused builds, such as small servers or workstations that need error checking. Its 45W TDP is higher, but that is a reasonable trade-off for the performance lead. The i5, on the other hand, is more appropriate for a laptop or compact mobile system where the 28W TDP and integrated Iris Pro Plus 655 graphics are sufficient.

Given that both CPUs sit at the 44th percentile and have average benchmark scores within 2 points of each other (1989 vs 1987), the choice ultimately depends on platform and workload. For maximum Cinebench performance, choose the Xeon. For a lower-power mobile solution with Geekbench results in the 1209 single-core and 3764 multi-core range, the i5 is the only option. The Xeon wins the performance crown, but the i5 wins on power efficiency.