Intel Core i5-2550K vs Intel Xeon D-1518 Comparison

Head-to-Head Benchmarks

The recorded benchmark data shows a consistent, if modest, advantage for the Intel Xeon D-1518 across every single test in the database. The Xeon D-1518 wins all six head-to-head comparisons, with the Core i5-2550K trailing by a narrow margin in each discipline.

In Cinebench R15 multicore, the Xeon D-1518 scores 390 against 365 for the i5-2550K, a 6.4% deficit for the older desktop chip. The single-core R15 test tells a similar story: 54 for the Xeon versus 51 for the i5, a 5.6% gap. Moving to Cinebench R20, the multicore result is 1628 for the Xeon and 1523 for the i5, again a 6.4% difference. Single-core R20 sees 229 versus 215, a 6.1% gap.

Cinebench R23 repeats the pattern. Multicore shows 3877 for the Xeon D-1518 and 3628 for the i5-2550K, another 6.4% separation. Single-core R23 gives 547 versus 512, also 6.4%. The consistency of these deltas is striking; the Xeon D-1518 leads by roughly 6% in nearly every workload measured, suggesting a systematic architectural edge rather than a test-specific quirk.

It is worth remembering the i5-2550K does have a higher base clock, at 3.40 GHz versus 2.20 GHz for the Xeon. The i5 also has a boost clock of 3.80 GHz while the Xeon lists no boost clock at all. Yet despite that clock disadvantage, the Xeon still wins every benchmark. The reason lies in the architecture and thread count, which will be covered in later sections. For now, the headline is simple: the Xeon D-1518 outperforms the i5-2550K in every recorded test, with margins between 5.6% and 6.4%.

The average benchmark score in the database reflects this as well. The i5-2550K sits at 1136, while the Xeon D-1518 sits at 1121. Both CPUs land at the 32nd percentile versus all CPUs in the database, meaning they occupy the same overall performance tier despite the Xeon's head-to-head wins. The i5's nearest rivals include the Intel Core i5-3570T at a 0% delta, the Intel Xeon E5640 at -0.1%, and the Intel Core i3-N300 at 0.1%. The Xeon D-1518's nearest rivals are the AMD Athlon 240GE at 0%, the Intel Core i7-2860QM at 0.1%, and the Intel Core i3-4150 at 0.2%. These are different peer groups, but the overall percentile ranking is identical.

The Verdict

The data supports a straightforward conclusion: the Intel Xeon D-1518 is the faster processor in every measured workload. If the only criterion is benchmark performance, the Xeon wins outright. The six head-to-head results are unanimous, and the margins, while not large, are consistent and reproducible across three different Cinebench versions and both single-core and multicore tests.

Who should pick the i5-2550K? The data shows it is an end-of-life desktop part with an unlocked multiplier, a feature the Xeon lacks. It also has a higher base clock and a boost clock, which matters in scenarios where clock speed is the dominant factor. However, the benchmark results do not reflect any advantage from that higher clock; the Xeon still wins single-core tests despite running at a lower base frequency. The i5 also has a lower average benchmark score (1136 versus 1121), though that difference is within the noise of the nearest-rival comparisons.

Who should pick the Xeon D-1518? Anyone prioritizing raw performance, lower power consumption, ECC memory support, PCIe Gen 3, and active production status. The Xeon is a server/workstation part with 8 threads versus 4, and it delivers that thread advantage in every test. It is also still in production, whereas the i5 is end-of-life. The Xeon carries a launch MSRP of $193, while the i5 launched at $235, but pricing is not a factor in this analysis. The performance data alone favors the Xeon.

Architecture Differences

The two processors come from different architectural eras and design philosophies. The i5-2550K is built on Sandy Bridge, a 32 nm process, with 1,160 million transistors on a 216 mm² die. The Xeon D-1518 uses Broadwell, a 14 nm process, with 3,200 million transistors on a 246 mm² die. The process shrink is substantial, and the transistor count nearly triples, yet the die size grows only modestly. This explains the Xeon's power efficiency advantage, though power figures are not the focus here.

Cache layouts differ significantly. Both chips have 64 KB of L1 cache per core and 256 KB of L2 per core. The L3 cache, however, is organized differently. The i5-2550K has 6 MB of shared L3 cache. The Xeon D-1518 has 1.5 MB of L3 per core, which for a 4-core chip totals 6 MB as well. The per-core allocation on the Xeon means each core gets dedicated L3, whereas the i5 uses a shared pool. This can affect performance in different workloads, though the benchmark results show the Xeon ahead regardless.

Thread support is a major architectural split. The i5-2550K has 4 cores and 4 threads, meaning no Hyper-Threading. The Xeon D-1518 has 4 cores and 8 threads, effectively doubling the thread count. This is the most likely explanation for the Xeon's multicore wins. The single-core wins are less obvious, but the Broadwell architecture's newer design and higher instructions-per-clock likely compensate for the lower clock speed.

The memory controllers also differ. The i5 supports DDR3 only, while the Xeon supports both DDR3 and DDR4. The i5 has a dual-channel memory bus with a recorded bandwidth of 25.6 GB/s. The Xeon also has a dual-channel bus, but no bandwidth figure is listed. ECC memory is supported on the Xeon but not on the i5, an important distinction for server and workstation reliability.

PCIe support is another differentiator. The i5-2550K provides PCIe Gen 2 with 16 lanes from the CPU. The Xeon D-1518 provides PCIe Gen 3 with 24 lanes. That is a full generation newer and 8 additional lanes, which matters for I/O-heavy systems.

Specification Differences

The two chips differ in several key specifications. The i5-2550K has 4 cores and 4 threads, while the Xeon D-1518 has 4 cores and 8 threads. Base clocks are 3.40 GHz for the i5 and 2.20 GHz for the Xeon. The i5 has a boost clock of 3.80 GHz; the Xeon lists no boost clock. TDP ratings differ substantially: 95 watts for the i5, 35 watts for the Xeon. The socket is different as well: Intel Socket 1155 for the i5, Intel BGA 1667 for the Xeon. The process node is 32 nm for the i5 and 14 nm for the Xeon.

L3 cache is 6 MB shared on the i5, and 1.5 MB per core on the Xeon. Memory support is DDR3 for the i5, and DDR3 plus DDR4 for the Xeon. ECC memory is not supported on the i5, but is supported on the Xeon. PCIe is Gen 2 with 16 lanes for the i5, and Gen 3 with 24 lanes for the Xeon. The multiplier is unlocked on the i5, locked on the Xeon. Market segments are Desktop for the i5 and Server/Workstation for the Xeon. Production status is End-of-life for the i5 and Active for the Xeon. Release dates are January 2012 for the i5 and March 2015 for the Xeon. Transistor counts are 1,160 million for the i5 and 3,200 million for the Xeon. Die sizes are 216 mm² and 246 mm², respectively.

FAQ

Q: Which processor is faster in single-core benchmarks?

A: The Intel Xeon D-1518 wins every single-core test in the database. It scores 54, 229, and 547 in Cinebench R15, R20, and R23 respectively, against 51, 215, and 512 for the i5-2550K.

Q: How much faster is the Xeon D-1518 in multicore workloads?

A: The Xeon D-1518 leads by 6.4% in Cinebench R15 multicore (390 versus 365), 6.4% in R20 multicore (1628 versus 1523), and 6.4% in R23 multicore (3877 versus 3628).

Q: Does the i5-2550K have any advantages in the specification sheet?

A: Yes. The i5 has a higher base clock (3.40 GHz versus 2.20 GHz), a boost clock of 3.80 GHz (the Xeon has none), an unlocked multiplier, and a lower average benchmark score is not an advantage, but the higher clocks and unlocked multiplier are notable. It also has a smaller die size at 216 mm² versus 246 mm².

Q: Which processor supports ECC memory?

A: Only the Intel Xeon D-1518 supports ECC memory. The i5-2550K does not.

Q: Are these processors in the same performance percentile?

A: Yes, both are at the 32nd percentile versus all CPUs in the database. The i5-2550K has an average benchmark score of 1136, while the Xeon D-1518 has an average score of 1121.

Q: Which processor has more PCIe lanes and a newer PCIe generation?

A: The Xeon D-1518 has PCIe Gen 3 with 24 lanes, while the i5-2550K has PCIe Gen 2 with 16 lanes.

Where Each One Wins

The Intel Xeon D-1518 wins in every benchmark category recorded. It takes all six head-to-head matchups, covering single-core and multicore tests across Cinebench R15, R20, and R23. The margins range from 5.6% to 6.4%, with the multicore tests consistently showing a 6.4% gap and the single-core tests showing 5.6% to 6.4%. The Xeon also wins on thread count (8 versus 4), ECC support, PCIe Gen 3, memory flexibility (DDR3 and DDR4), process node (14 nm versus 32 nm), transistor count (3,200 million versus 1,160 million), and production status (Active versus End-of-life). Its TDP is also far lower at 35 watts versus 95 watts.

The i5-2550K wins on raw clock speeds. It has a higher base clock (3.40 GHz versus 2.20 GHz) and is the only one of the two with a boost clock (3.80 GHz). It also has an unlocked multiplier, which the Xeon lacks, making it the more overclockable part. The i5 uses a shared 6 MB L3 cache, while the Xeon uses a per-core split of 1.5 MB per core, which some workloads may handle differently. The i5 also has a smaller die size (216 mm² versus 246 mm²) and fewer transistors, which is not a performance win but reflects a simpler design. Its average benchmark score is slightly higher at 1136 versus 1121, though the Xeon wins all direct comparisons.

The use-case split follows from this data. For a desktop builder who values overclocking, the i5-2550K is the only choice with an unlocked multiplier and a boost clock. For a server or workstation builder who needs ECC memory, PCIe Gen 3, and lower power draw, the Xeon D-1518 is the clear pick. For raw benchmark performance, the Xeon wins every test, so it is the stronger processor by the numbers. The i5's higher clocks do not translate into benchmark wins, which suggests the Xeon's newer architecture and additional threads are the decisive factors.