Intel Core i5-6600 vs Intel Xeon E3-1265L v4 Comparison

FAQ

Q: Which CPU has the higher boost clock, and how does that affect single-core performance?

A: The Intel Core i5-6600 boosts to 3.90 GHz, while the Intel Xeon E3-1265L v4 boosts to 3.30 GHz. Despite the i5's higher boost clock, the Xeon wins every single-core benchmark in the head-to-head comparisons, including Cinebench R23 single-core by 12.7% (728 vs 834). This suggests the Xeon's architecture extracts more performance per clock in this workload.

Q: How do the two CPUs compare in multi-threaded workloads?

A: The Xeon E3-1265L v4 wins all three multi-core Cinebench tests by roughly 12.6% to 12.7%. For example, in Cinebench R23 multi-core, the Xeon scores 5910 versus the i5-6600's 5161. The Xeon's 8 threads versus the i5's 4 threads provide a clear advantage in parallel rendering tasks.

Q: What is the average benchmark score difference between these two CPUs?

A: The Core i5-6600 has an average benchmark score of 1744, while the Xeon E3-1265L v4 averages 1709. This is a 2% difference in favor of the i5, even though the Xeon wins all six head-to-head tests. The i5's average is bolstered by its Geekbench scores, which are not shared with the Xeon in the comparison set.

Q: Do both CPUs support the same memory types?

A: No. The Core i5-6600 supports both DDR3 and DDR4 memory, while the Xeon E3-1265L v4 supports only DDR3. Both use a dual-channel memory bus, but the i5 has a higher memory bandwidth at 34.1 GB/s versus the Xeon's 29.9 GB/s.

Q: Which CPU has ECC memory support?

A: The Xeon E3-1265L v4 supports ECC memory, while the Core i5-6600 does not. This makes the Xeon more suitable for error-sensitive server or workstation environments, even though both are end-of-life products.

Q: How do their integrated graphics compare?

A: The Core i5-6600 features UHD Graphics 530, while the Xeon E3-1265L v4 features Intel Iris Pro P6300. The database does not provide direct benchmark comparisons for these iGPUs, but the Xeon's Iris Pro line is positioned as a more capable graphics solution for its era.

The Verdict

The recorded data points to a clear winner in raw performance: the Intel Xeon E3-1265L v4 wins all six head-to-head benchmark comparisons against the Core i5-6600. The Xeon's advantage ranges from 12.6% to 13.1% across Cinebench R15, R20, and R23 tests. For anyone prioritizing multi-threaded rendering or single-core Cinebench performance, the Xeon is the stronger pick.

However, the Core i5-6600 has its own merits. It supports both DDR3 and DDR4 memory, offers a higher memory bandwidth (34.1 GB/s versus 29.9 GB/s), and carries a higher average benchmark score (1744 versus 1709). The i5 also features a higher boost clock (3.90 GHz versus 3.30 GHz) and a newer socket (Intel Socket 1151 versus Intel Socket 1150). The i5's average score is influenced by Geekbench results, where it scores 3755 multi-core and 1239 single-core, tests not run on the Xeon in this dataset.

The Xeon is the choice for sustained compute workloads, especially those that benefit from 8 threads and ECC memory support. The i5-6600 is the pick for users who need DDR4 compatibility or a more flexible memory setup, and who can accept lower Cinebench scores. Both CPUs sit near the 40th percentile among all CPUs (i5: 41, Xeon: 40), indicating they are mid-pack performers in the broader database.

Head-to-Head Benchmarks

The Xeon E3-1265L v4 dominates every benchmark in the head-to-head comparison. In Cinebench R15 multi-core, the Xeon scores 595 against the i5-6600's 520, a 12.6% deficit for the i5. The single-core R15 test shows a similar gap: 84 for the Xeon versus 73 for the i5, a 13.1% difference. These are the largest percentage gaps in the dataset.

Moving to Cinebench R20, the Xeon leads 2482 versus 2167 in multi-core (12.7% ahead) and 350 versus 305 in single-core (12.9% ahead). The pattern holds in Cinebench R23: the Xeon scores 5910 multi-core and 834 single-core, while the i5 scores 5161 and 728 respectively, both 12.7% behind.

The consistency is notable. Every single benchmark, regardless of workload type or Cinebench version, shows the Xeon ahead by roughly 12.6% to 13.1%. The i5-6600 has zero wins in the head-to-head set. The Xeon's 8 threads versus 4 threads explain the multi-core advantage, but the single-core wins are more surprising given the i5's higher boost clock. The Xeon's Broadwell architecture appears to deliver better instructions per clock in these tests.

The i5's Geekbench scores (3755 multi-core, 1239 single-core) are not part of the head-to-head comparison, so they cannot be directly contrasted with Xeon results. But they do contribute to the i5's higher average benchmark score of 1744, slightly above the Xeon's 1709.

Specification Differences

The two CPUs differ in several key specifications. The Core i5-6600 has 4 cores and 4 threads, while the Xeon E3-1265L v4 has 4 cores and 8 threads. Base clocks differ: the i5 runs at 3.30 GHz, the Xeon at 2.30 GHz. Boost clocks also differ: 3.90 GHz for the i5, 3.30 GHz for the Xeon.

Sockets are different: the i5 uses Intel Socket 1151, the Xeon uses Intel Socket 1150. Memory support diverges: the i5 supports DDR3 and DDR4, the Xeon only DDR3. Memory bandwidth favors the i5 at 34.1 GB/s versus 29.9 GB/s. ECC memory is supported only on the Xeon.

The integrated graphics differ: UHD Graphics 530 on the i5, Intel Iris Pro P6300 on the Xeon. The die size is slightly different: 177 mm² for the i5, 182 mm² for the Xeon. Both are 14 nm parts on a dual-channel memory bus with PCIe Gen 3 and 16 CPU lanes. Both have 64 KB L1 and 256 KB L2 per core, and 6 MB shared L3 cache. Neither has an unlocked multiplier. Both are end-of-life products, with the i5 released on 2015-06-30 and the Xeon on 2015-06-01. The launch MSRP for the i5 is $224, while the Xeon's launch MSRP is $417.

Architecture Differences

The Core i5-6600 is built on the Skylake architecture (codename Skylake) and belongs to the Core i5 generation. The Xeon E3-1265L v4 uses the Broadwell architecture (codename Broadwell-DT) and belongs to the Xeon E3 generation. Both are manufactured on Intel's 14 nm process, but the underlying microarchitectures differ significantly.

Skylake was Intel's desktop-focused architecture for the 6th generation Core series, while Broadwell-DT was a server and workstation-oriented design. This explains the Xeon's ECC memory support and its 8-thread configuration despite having 4 physical cores. The Xeon's base clock is lower (2.30 GHz versus 3.30 GHz), but its architectural efficiency appears to compensate, as shown by its consistent benchmark wins.

The die sizes are close: 177 mm² for Skylake, 182 mm² for Broadwell-DT. Both have identical cache hierarchies: 64 KB L1 per core, 256 KB L2 per core, and 6 MB shared L3. The Xeon's integrated graphics, Iris Pro P6300, is a more advanced iGPU solution than the i5's UHD Graphics 530, likely reflecting its workstation positioning. The Xeon's memory bandwidth is lower (29.9 GB/s versus 34.1 GB/s), partly due to its DDR3-only support, while the i5's broader memory compatibility allows DDR4 with higher bandwidth.

Where Each One Wins

The Xeon E3-1265L v4 wins every Cinebench test in the head-to-head set. This includes all multi-core and single-core variants of R15, R20, and R23. For users running Cinebench-style rendering workloads, the Xeon is decisively faster. Its 8 threads give it a structural advantage in multi-threaded tasks, and its single-core performance is also superior despite a lower boost clock. The Xeon also supports ECC memory, making it the safer choice for data integrity in server or workstation use cases.

The Core i5-6600 wins in areas not covered by the head-to-head benchmarks. Its average benchmark score is higher (1744 versus 1709), driven by Geekbench results where it scores 3755 multi-core and 1239 single-core. The i5 supports both DDR3 and DDR4, giving users more memory upgrade options, and it has higher memory bandwidth (34.1 GB/s versus 29.9 GB/s). Its boost clock is higher (3.90 GHz versus 3.30 GHz), which may benefit lightly threaded applications that are not represented in the Cinebench tests. The i5 also uses the newer Socket 1151, which may offer broader motherboard compatibility for desktop builds.

For a desktop user who values Geekbench performance, memory flexibility, or DDR4 support, the Core i5-6600 is the better fit. For a user who prioritizes Cinebench rendering, ECC memory, or thread count, the Xeon E3-1265L v4 is the clear choice. The data shows a trade-off: the Xeon wins the measured benchmarks outright, but the i5 holds advantages in memory support, bandwidth, and its overall average score.