Intel Core i5-6600K vs Intel Xeon E3-1505M v5 Comparison

The Intel Xeon E3-1505M v5 and the Intel Core i5-6600K are both Skylake-era Intel processors, yet they are engineered for entirely different environments. The Xeon is a mobile workstation chip, while the i5 is a desktop enthusiast part. Despite this, their average benchmark scores are nearly identical, with the Xeon at 1817 and the i5 at 1816, a difference of only 0.1%. This close aggregate, however, masks a stark divergence in individual workload performance, where the Xeon consistently outperforms the i5 across the board in all tested Cinebench iterations.

Where Each One Wins

The data presents an unusual case: the Intel Xeon E3-1505M v5 wins all six head-to-head benchmark comparisons against the Intel Core i5-6600K. There is no benchmark category, whether single-core or multi-core, where the i5-6600K manages to take the lead. This means that for pure compute performance as measured by Cinebench, the Xeon is the unambiguous victor. The Xeon’s advantage is not marginal; it consistently posts a delta of over 17% in every test. For users running CPU-intensive tasks like 3D rendering or video encoding, the Xeon's lead in multi-threaded workloads is particularly relevant, as it suggests notably faster completion times.

The Core i5-6600K’s wins are not in raw performance but in its feature set. It is the only one of the two with an unlocked multiplier, indicating it is designed for overclocking. It also has a higher base and boost clock speed, at 3.50 GHz and 3.90 GHz respectively, compared to the Xeon’s 2.80 GHz and 3.70 GHz. This suggests that in scenarios where the i5’s clock speed can be pushed further, it might close the gap, but the stock data shows it cannot overcome the Xeon’s efficiency. The i5 also has a lower launch MSRP of $242, but the Xeon’s $434 launch MSRP positions it in a different market segment. The i5 is the choice for a user who wants a customizable desktop platform, while the Xeon is the choice for a user who needs maximum out-of-the-box compute performance.

Architecture Differences

Both processors are built on Intel’s 14 nm process node and share the Skylake architecture, but they are distinct variants. The Xeon E3-1505M v5 is part of the Skylake-H family, designed for mobile workstations, and uses the Intel BGA 1440 socket. In contrast, the Core i5-6600K is a desktop part from the standard Skylake family, fitting into the Intel Socket 1151. This fundamental difference explains their contrasting specifications. The Xeon’s mobile orientation is reflected in its 45 W TDP, a far cry from the i5-6600K’s 91 W TDP, which is more suited for a desktop with a dedicated cooling solution.

The most significant architectural difference is in threading and cache. The Xeon E3-1505M v5 supports Hyper-Threading, offering 4 cores and 8 threads, while the Core i5-6600K has 4 cores and 4 threads, lacking this feature. This is a primary reason for the Xeon’s superior multi-core performance. The Xeon also boasts a larger 8 MB shared L3 cache compared to the i5-6600K’s 6 MB. Both have the same 64 KB L1 and 256 KB L2 cache per core. Another key distinction is ECC memory support. The Xeon supports ECC memory, a feature critical for data integrity in server and workstation environments, whereas the i5-6600K does not. The Xeon also integrates the HD Graphics P530, while the i5 features the HD Graphics 530, suggesting a different focus for their integrated graphics solutions.

Head-to-Head Benchmarks

The benchmark results are remarkably consistent, showing a uniform performance gap across all tests. In Cinebench R15, the Xeon E3-1505M v5 scores 633 in the multi-core test, a 17.2% advantage over the i5-6600K’s 540. In the single-core test, the Xeon scores 89 versus the i5’s 76, a 17.1% lead. This pattern repeats in Cinebench R20, where the Xeon’s multi-core score of 2639 beats the i5’s 2252, again by 17.2%. The single-core result in R20 shows a similar trend, with the Xeon at 372 and the i5 at 317, a 17.4% difference.

The most recent benchmark, Cinebench R23, continues this trend. The Xeon achieves a multi-core score of 6284, outperforming the i5-6600K’s 5363 by 17.2%. In the single-core test, the Xeon scores 887, while the i5 scores 757, another 17.2% margin. This consistency across multiple generations of the same benchmark is striking. It indicates that the Xeon’s performance advantage is not tied to a specific workload type but is a fundamental characteristic of the chip. This is likely due to the combination of Hyper-Threading and a larger cache, which allows the Xeon to process instructions more efficiently, even in single-threaded tasks where its lower base clock would seem to be a disadvantage. The data suggests that the Xeon’s architecture is simply more efficient at executing these rendering instructions.

Specification Differences

The two processors diverge on several key specification points. The most obvious is the core and thread count: the Xeon E3-1505M v5 has 4 cores and 8 threads, whereas the Core i5-6600K has 4 cores and 4 threads. This is a direct result of Hyper-Threading technology being present on the Xeon but absent on the i5. Their clock speeds also differ, with the i5-6600K having a higher base clock of 3.50 GHz and boost clock of 3.90 GHz, compared to the Xeon’s 2.80 GHz and 3.70 GHz. The TDP is a major differentiator, with the Xeon rated at 45 W and the i5 at 91 W.

Other differences include the socket type, with the Xeon using Intel BGA 1440 and the i5 using Intel Socket 1151. The L3 cache size is different, as the Xeon has 8 MB while the i5 has 6 MB. ECC memory support is exclusive to the Xeon. The integrated graphics differ, with the Xeon featuring HD Graphics P530 and the i5 featuring HD Graphics 530. The Xeon’s market segment is listed as Server/Workstation, while the i5’s is Desktop. Finally, the multiplier is unlocked on the i5-6600K but locked on the Xeon, and the part numbers are SR2FM for the Xeon and SR2L4 for the i5. The Xeon’s launch MSRP is $434, while the i5’s is $242.

FAQ

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

A: The Intel Xeon E3-1505M v5 is significantly faster. In Cinebench R23 multi-core, it scores 6284 compared to the Core i5-6600K’s 5363, a 17.2% advantage.

Q: Does the Core i5-6600K win in any benchmark?

A: No. Based on the data, the Xeon E3-1505M v5 wins all six head-to-head benchmark comparisons, including both single-core and multi-core tests.

Q: What is the main reason for the Xeon’s performance lead?

A: The Xeon E3-1505M v5 has 8 threads compared to the i5-6600K’s 4 threads, and it also has a larger 8 MB L3 cache versus 6 MB. This combination likely contributes to its consistent 17% performance advantage.

Q: Are these processors on the same socket?

A: No. The Xeon E3-1505M v5 uses the Intel BGA 1440 socket, while the Core i5-6600K uses the Intel Socket 1151.

Q: Which processor is designed for overclocking?

A: The Core i5-6600K has an unlocked multiplier, indicating it is designed for overclocking. The Xeon E3-1505M v5 has a locked multiplier.

Q: What is the difference in their power consumption?

A: The Xeon E3-1505M v5 has a TDP of 45 W, while the Core i5-6600K has a TDP of 91 W, making the Xeon a much more power-efficient part.

The Verdict

The benchmark data is clear: the Intel Xeon E3-1505M v5 is the superior processor for raw computational performance. It wins every single benchmark test, with a consistent 17% lead over the Intel Core i5-6600K in both single and multi-core Cinebench workloads. This makes it the obvious choice for professionals using applications that rely heavily on CPU rendering or number crunching, such as 3D modeling, scientific simulation, or video editing, where that performance delta translates directly to reduced wait times.

However, the Core i5-6600K is not without its own merits, though they lie outside of the tested benchmarks. Its unlocked multiplier and higher stock clock speeds make it the preferred option for desktop enthusiasts who intend to overclock. Its lower 91 W TDP is still a consideration but is typical for a desktop part. For a user building a gaming or general-purpose desktop who plans to tweak their system, the i5-6600K offers a platform for customization. But for a user who needs a dependable, high-performance mobile workstation that is faster out of the box, the Xeon E3-1505M v5 is the clear winner. The data shows that the Xeon’s efficiency and threading advantage make it the better choice for demanding professional workloads, while the i5 is a different tool for a different job.