Intel Core i5-8400T vs Intel Xeon E3-1285L v4 Comparison

The Intel Core i5-8400T and Intel Xeon E3-1285L v4 are two end-of-life processors from different Intel eras, and the benchmark data reveals a surprisingly consistent performance hierarchy between them. Despite the i5-8400T having two more physical cores, the older Xeon E3-1285L v4 wins every single head-to-head benchmark in the dataset, making for a clear, if counterintuitive, performance story that hinges on clock speed and architecture generation.

Head-to-Head Benchmarks

The data is unambiguous: the Intel Xeon E3-1285L v4 wins all six head-to-head comparisons, with the i5-8400T trailing by a nearly identical margin across every test. In Cinebench R15 multi-core, the Xeon scores 693 against the i5-8400T’s 633, a delta of -8.7% for the i5. The single-core R15 test shows a similar pattern, with the Xeon at 97 and the i5 at 89, a -8.2% difference. This consistency suggests a fundamental clock-speed advantage rather than a workload-specific quirk.

Moving to Cinebench R20, the Xeon again leads in multi-core with 2891 versus 2638, and in single-core with 407 versus 372, both showing a -8.8% and -8.6% delta respectively. The most modern test, Cinebench R23, continues the trend: the Xeon posts 6884 multi-core and 971 single-core, while the i5-8400T manages 6282 and 886, with deltas of -8.7% and -8.8%. The fact that the i5-8400T loses by roughly 8-9% in every test, regardless of thread count or test generation, indicates the Xeon’s higher base and boost clocks are the dominant factor.

It is notably the i5-8400T’s average benchmark score of 2001 places it at the 45th percentile of all CPUs, while the Xeon’s 1991 average sits at the 44th percentile. These are nearly identical overall standing positions, yet the head-to-head data shows the Xeon winning every time. The i5-8400T’s nearest rivals include the AMD Ryzen 7 2800H at an average score of 2002 and the Intel Core i5-8400H at 2003, with deltas of 0% and -0.1% respectively. The Xeon’s rivals include the AMD Ryzen 5 1500X at 1992 and the Intel Core i7-7920HQ at 1992, both with a 0% delta. This shows both processors are in the same performance tier, yet the Xeon’s edge in the direct comparison is decisive.

Where Each One Wins

Based strictly on the benchmark results, the Intel Xeon E3-1285L v4 wins in every measurable category. It holds a consistent advantage in both single-core and multi-core workloads across Cinebench R15, R20, and R23. For users prioritizing raw rendering performance in CPU-bound tasks like video encoding or 3D rendering, the Xeon’s higher scores in multi-core tests (693, 2891, and 6884) make it the clear choice. Its single-core wins (97, 407, and 971) also suggest better responsiveness in lightly-threaded applications, such as older games or basic office productivity.

The Intel Core i5-8400T, however, does not win a single benchmark in the dataset. Its wins are zero, and the Xeon takes all six. This means the i5-8400T has no practical use case advantage in the tested workloads. However, the i5-8400T does have a significantly lower TDP of 35 watts compared to the Xeon’s 65 watts, which is a qualitative advantage for power-constrained systems, though this is not reflected in the benchmark scores. The i5-8400T also supports DDR4 memory with a higher theoretical bandwidth of 42.7 GB/s versus the Xeon’s DDR3 at 29.9 GB/s, but again, this does not translate into a performance win in the Cinebench tests.

The data implies the Xeon’s higher clock speeds (3.40 GHz base, 3.80 GHz boost) simply overpower the i5-8400T’s two extra cores (6 versus 4) and its lower clocks (1.70 GHz base, 3.30 GHz boost). The i5-8400T’s eight threads (6 cores, 6 threads) are actually fewer than the Xeon’s eight threads (4 cores, 8 threads), but the core count difference does not compensate for the clock deficit. In essence, the Xeon wins everywhere, making the i5-8400T a poor choice for performance-focused builds based on this data.

Architecture Differences

The two processors come from different architectural generations and are built for different sockets. The Intel Core i5-8400T uses the Coffee Lake architecture on the Intel Socket 1151, while the Intel Xeon E3-1285L v4 uses the older Broadwell architecture on the Intel Socket 1150. Both are fabricated on Intel’s 14 nm process node, but the die sizes differ slightly: the i5-8400T has a 154 mm² die, while the Xeon has a 160 mm² die and contains 1,400 million transistors, a figure not listed for the i5.

Cache configurations also diverge. Both have 64 KB of L1 cache and 256 KB of L2 cache per core. However, the i5-8400T has a larger shared L3 cache of 9 MB, while the Xeon offers only 6 MB. This larger cache on the i5-8400T could theoretically help in some workloads, but the benchmark data shows it does not overcome the Xeon’s clock advantage. The memory support differs as well: the i5-8400T uses DDR4 in a dual-channel configuration with 42.7 GB/s bandwidth, while the Xeon uses DDR3 with 29.9 GB/s. The Xeon also supports ECC memory, a feature absent on the i5-8400T, which is relevant for server or workstation reliability.

Integrated graphics are another point of divergence. The i5-8400T includes UHD Graphics 630, while the Xeon packs Intel Iris Pro P6300. The Xeon’s integrated GPU is generally more capable, but neither is a substitute for a discrete graphics card. Finally, the PCIe support is listed as Gen 3 with 16 lanes on the CPU for the i5-8400T, while the Xeon simply lists Gen 3 without a lane count. These architectural differences explain why the Xeon, despite being older and having fewer cores, can outperform the i5-8400T in synthetic benchmarks.

The Verdict

The data strongly favors the Intel Xeon E3-1285L v4 for anyone prioritizing raw CPU performance. It wins all six head-to-head benchmarks, with margins ranging from -8.2% to -8.8% in the i5-8400T’s favor. The Xeon’s higher base clock (3.40 GHz versus 1.70 GHz) and boost clock (3.80 GHz versus 3.30 GHz) are the likely drivers of this consistent advantage, allowing it to outperform the i5-8400T’s two additional cores. The Xeon’s 4 cores and 8 threads are sufficient to beat the i5-8400T’s 6 cores and 6 threads in multi-core tests, meaning the i5’s core advantage is nullified in practice.

The i5-8400T does have its merits, including a lower TDP of 35 watts, which could make it suitable for compact or low-power builds, and support for faster DDR4 memory. However, in terms of benchmark performance, it loses every test. The Xeon’s ECC memory support and server/workstation market segment make it a more robust choice for professional environments where data integrity is critical. Given that the Xeon has a higher launch MSRP of $445 compared to the i5-8400T’s $182, the i5 is the more accessible option, but the performance data suggests the Xeon justifies its premium for those who need maximum throughput. Based on the numbers, the Xeon E3-1285L v4 is the superior processor for all tested workloads.

FAQ

Q: Which processor wins the most benchmarks?

A: The Intel Xeon E3-1285L v4 wins all six head-to-head benchmarks against the Intel Core i5-8400T, including Cinebench R15, R20, and R23 in both single-core and multi-core tests.

Q: What is the biggest performance gap between the two?

A: The largest delta is -8.8%, seen in Cinebench R20 multi-core (2638 vs 2891) and Cinebench R23 single-core (886 vs 971), where the i5-8400T trails the Xeon.

Q: Does the i5-8400T have more cores than the Xeon?

A: Yes, the i5-8400T has 6 cores and 6 threads, while the Xeon has 4 cores and 8 threads. Despite fewer cores, the Xeon still wins all multi-core benchmarks.

Q: What are the clock speed differences?

A: The i5-8400T has a base clock of 1.70 GHz and a boost clock of 3.30 GHz, while the Xeon has a base clock of 3.40 GHz and a boost clock of 3.80 GHz.

Q: Do the two processors support the same memory type?

A: No, the i5-8400T supports DDR4 memory with a bandwidth of 42.7 GB/s, while the Xeon supports DDR3 with a bandwidth of 29.9 GB/s. The Xeon also supports ECC memory, which the i5 does not.

Q: What are the average benchmark scores for each?

A: The i5-8400T has an average benchmark score of 2001, placing it at the 45th percentile, while the Xeon has an average score of 1991, placing it at the 44th percentile.

Specification Differences

| Specification | Intel Core i5-8400T | Intel Xeon E3-1285L v4 |

|----------------|---------------------|-------------------------|

| Cores | 6 | 4 |

| Threads | 6 | 8 |

| Base Clock | 1700.00 MHz | 3.40 GHz |

| Boost Clock | 3.30 GHz | 3.80 GHz |

| TDP | 35 W | 65 W |

| Socket | Intel Socket 1151 | Intel Socket 1150 |

| Architecture | Coffee Lake | Broadwell |

| Codename | Coffee Lake | Broadwell-DT |

| Generation | Core i5 (Coffee Lake) | Xeon E3 (Broadwell-DT) |

| Transistors | Not listed | 1,400 million |

| Die Size | 154 mm² | 160 mm² |

| L3 Cache | 9 MB (shared) | 6 MB (shared) |

| Memory Support | DDR4 | DDR3 |

| Memory Bandwidth | 42.7 GB/s | 29.9 GB/s |

| ECC Memory | No | Yes |

| PCIe | Gen 3, 16 Lanes (CPU only) | Gen 3 |

| Integrated Graphics | UHD Graphics 630 | Intel Iris Pro P6300 |

| Market Segment | Desktop | Server/Workstation |

| Launch MSRP | $182 | $445 |

| Part Number | SR3X6 | SR2B1 |