Intel Core i7-5820K vs Intel Xeon E5-1650 v3 Comparison

Head-to-Head Benchmarks

The recorded benchmark data shows a consistent, though not overwhelming, advantage for the Intel Xeon E5-1650 v3 across every single test in the comparison suite. Out of six head-to-head comparisons, the Xeon wins all six, with margins that hover in a narrow band between 5.3% and 5.9%.

The largest single-core victory comes in Cinebench R15 single-core, where the Xeon scores 125 against the Core i7-5820K's 118, a 5.9% gap. That pattern repeats in the R20 single-core test, with the Xeon posting 521 versus 495, a 5.3% difference. In Cinebench R23 single-core, the Xeon records 1242 against 1179, again 5.3% ahead. These results indicate that the Xeon's higher base and boost clocks translate directly into per-thread performance gains, with the single-core spread remaining remarkably stable across all three Cinebench versions.

Multi-core results tell a similar story. The Xeon leads by 5.5% in Cinebench R15 multi-core, scoring 887 to the i7's 841. The R20 multi-core test shows the Xeon at 3696 versus 3508, a 5.4% edge. In the most demanding test, Cinebench R23 multi-core, the Xeon reaches 8800 while the i7 manages 8354, again a 5.3% margin. The consistency of these deltas is notable: whether the workload is light or heavy, the Xeon maintains a lead of roughly five and a half percent, suggesting the advantage comes from clock speed rather than any workload-specific architectural quirk.

The average benchmark scores place the two processors in the same performance neighborhood. The Xeon's average across its tested benchmarks is 2545, while the i7's average is 2642. That said, the i7's average includes Geekbench results that the Xeon was not measured on, so the figures are not directly comparable. Both CPUs sit at the 49th percentile among all recorded CPUs, which places them squarely in the middle of the database's performance distribution.

When placed against external rivals, both chips hold their ground. The Xeon's nearest competitor is the Intel Xeon E5-4640 v3, which scores 2550, a negligible 0.2% difference. It also trades blows with the AMD Ryzen 7 4800HS (2557, 0.4% slower) and leads the Intel Core i3-10325 (2530, 0.6% faster) and Intel Xeon E-2244G (2527, 0.7% faster). The i7's nearest rival is the Intel Xeon E-2274G at 2643, an exact tie, with the Intel Core i9-8950HK (2641) and Intel Core i7-1195G7 (2638) both within 0.1%. The Intel Core i7-7740X is 0.2% ahead at 2648. These tight deltas confirm that both processors are competitive with much newer silicon despite their age.

Architecture Differences

Both processors are built on the same fundamental Haswell architecture, with the Xeon using the Haswell-EP variant and the i7 using Haswell-E. Both are manufactured on Intel's 22 nm process at the same foundry, with identical transistor counts of 2,600 million and identical die sizes of 356 mm². The core configuration is also the same: six cores and twelve threads apiece.

The cache hierarchy is identical on paper. Each chip carries 64 KB of L1 per core, 256 KB of L2 per core, and a shared 15 MB L3 cache. Memory support is also aligned: both support DDR4 over a quad-channel memory bus with a theoretical bandwidth of 68.3 GB/s. Neither processor includes integrated graphics, so both require a discrete GPU.

The most significant clock differences favor the Xeon. Its base clock runs at 3.50 GHz with a boost of 3.80 GHz, while the i7 is set to 3.30 GHz base and 3.60 GHz boost. That 200 MHz advantage at both base and boost explains the benchmark deltas almost perfectly. Both chips have unlocked multipliers, so either can be overclocked, but the Xeon starts from a higher point.

The PCIe lane counts differ substantially. The Xeon exposes Gen 3 with 40 lanes from the CPU, while the i7 provides Gen 3 with 28 lanes. For systems that rely on multiple GPUs or many NVMe drives, that 12-lane gap matters. The Xeon also supports ECC memory, while the i7 does not. The Xeon is classified as a Server/Workstation part, whereas the i7 is a Desktop part, which explains the ECC and PCIe differences.

The Xeon's part number is QFSTSR20J, and the i7's is SR20S. Both were released within days of each other in early September 2014, with the i7 appearing on August 31 and the Xeon on September 7. Both are end-of-life products today.

Where Each One Wins

The data is unambiguous: the Intel Xeon E5-1650 v3 wins every benchmark in the comparison set. There is no recorded test where the Core i7-5820K takes the lead. That makes the use-case split easy for raw performance, but the surrounding specifications create a more nuanced picture.

The Xeon is the pick for workstation or server builds where ECC memory is required. Its 40 PCIe lanes also make it better suited to multi-GPU configurations or dense storage arrays. The 3.80 GHz boost clock gives it a small but consistent edge in both single-threaded and multi-threaded workloads, as shown by the 5.3% to 5.9% margins across the Cinebench suite. For users who value error-correcting memory and maximum expansion capacity, the Xeon is clearly the stronger option.

The i7-5820K, despite losing every head-to-head test, still holds appeal for desktop builders. Its 28 PCIe lanes are adequate for a single high-end GPU plus a couple of NVMe drives. It lacks ECC support, but most consumer platforms do not need it. The i7's average benchmark score of 2642 is actually higher than the Xeon's 2545, though that is because the i7's average includes Geekbench multi-core and single-core results that the Xeon was not subjected to. The i7 also matches or nearly matches several modern chips in the database, tying the Intel Xeon E-2274G and sitting within 0.1% of the Intel Core i9-8950HK and Intel Core i7-1195G7.

In practical terms, the Xeon is the better processor for compute-heavy tasks, especially those that can use all twelve threads. The i7 is the better fit for a traditional desktop where ECC is irrelevant and the PCIe lane count is sufficient. Both are unlocked, so enthusiasts can close the clock gap with overclocking, but the Xeon's stock advantage means it needs less effort to reach the same performance level.

FAQ

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

A: The Intel Xeon E5-1650 v3 wins every multi-core test in the comparison. It scores 887 in Cinebench R15 versus 841, 3696 in R20 versus 3508, and 8800 in R23 versus 8354. The margins range from 5.3% to 5.5%.

Q: How big is the single-core performance gap?

A: The Xeon leads by 5.9% in Cinebench R15 single-core (125 versus 118) and by 5.3% in both R20 (521 versus 495) and R23 (1242 versus 1179).

Q: Do both processors support ECC memory?

A: No. The Xeon E5-1650 v3 supports ECC memory, while the Core i7-5820K does not.

Q: What are the PCIe lane differences?

A: The Xeon provides 40 PCIe Gen 3 lanes from the CPU, while the i7 provides 28 PCIe Gen 3 lanes.

Q: Are the core and thread counts the same?

A: Yes, both have six cores and twelve threads, with 64 KB L1 and 256 KB L2 per core, plus 15 MB of shared L3 cache.

Q: How do these chips compare to modern CPUs in the database?

A: The Xeon's closest rival is the Intel Xeon E5-4640 v3 with a 0.2% difference, and it is 0.4% behind the AMD Ryzen 7 4800HS. The i7 ties the Intel Xeon E-2274G and is within 0.1% of the Intel Core i9-8950HK.

The Verdict

The benchmark data makes the Xeon E5-1650 v3 the clear winner in raw performance. It beats the Core i7-5820K in all six head-to-head tests, with every margin falling between 5.3% and 5.9%. The Xeon also offers ECC memory support and 40 PCIe lanes versus 28, making it the more capable platform for workstation and server duties. Its higher base and boost clocks, 3.50 GHz and 3.80 GHz against 3.30 GHz and 3.60 GHz, explain the consistent edge.

The Core i7-5820K is not without merit. It is a desktop part with an unlocked multiplier, and its average benchmark score of 2642 is higher than the Xeon's 2545, though that average includes Geekbench results the Xeon was not measured on. It matches the Intel Xeon E-2274G exactly and comes within 0.1% of the Intel Core i9-8950HK, so it remains competitive against much newer hardware. For a pure desktop build without ECC requirements and with modest PCIe needs, the i7 is a reasonable choice.

For anyone who needs maximum performance from the recorded data, ECC support, or extensive PCIe expansion, the Xeon E5-1650 v3 is the correct selection. For a desktop user who values the i7's higher average score and does not need workstation features, the i7-5820K still holds up. The data does not support picking the i7 for speed, but it does support picking it for its desktop-oriented feature set.