Intel Core i7-940 vs Intel Xeon X5550 Comparison

Where Each One Wins

Looking at the recorded benchmark data, the Intel Core i7-940 wins every single head-to-head comparison against the Intel Xeon X5550. That is a clean sweep: five wins out of five tests, with the Xeon X5550 taking zero victories. The margins are narrow, but they are consistent across both single-core and multi-core workloads.

The Core i7-940 asserts its advantage in multi-threaded rendering tasks. In Cinebench R15 multicore, it scores 264 against the Xeon's 259, a 1.9% lead. The gap persists in Cinebench R20 multicore, where the Core i7-940 posts 1102 versus 1083, a 1.8% margin. The same story unfolds in Cinebench R23 multicore: 2626 for the Core i7-940, 2580 for the Xeon X5550, again a 1.8% difference.

Single-core performance tells a similar tale, though with slightly different margins. The Core i7-940 leads by 2% in Cinebench R20 singlecore (155 versus 152) and by 1.6% in Cinebench R23 singlecore (370 versus 364). These are not transformative differences, but they show that the desktop part holds a slight edge even when only one thread is active.

The use-case split is therefore straightforward. If the choice is between these two specific processors, the Core i7-940 is the stronger performer in every measured workload. The Xeon X5550 does not win any category in this data set. However, the Xeon's positioning as a server or workstation part suggests its value lies elsewhere, such as platform features or reliability characteristics, not in raw Cinebench scores.

Architecture Differences

Both processors share the same fundamental Nehalem architecture, but they come from different families. The Core i7-940 is codenamed Bloomfield and belongs to the Core i7 generation, while the Xeon X5550 uses the Gainestown codename and sits in the Xeon lineup. Both are built on Intel's 45 nm process node, and both pack 731 million transistors on a 263 mm² die. The cache hierarchy is identical: 64 KB of L1 per core, 256 KB of L2 per core, and 8 MB of shared L3.

The clock speeds differ, and that explains the benchmark gap. The Core i7-940 runs at a base clock of 2.93 GHz with a boost clock of 3.20 GHz. The Xeon X5550 is slower on paper, with a 2.67 GHz base and 3.07 GHz boost. That approximately 0.26 GHz difference in base clock, and 0.13 GHz in boost, aligns with the observed performance deltas.

Memory support is also distinct. Both support DDR3 and use a triple-channel memory bus, but the Xeon X5550 adds ECC memory support, which the Core i7-940 lacks. That is a meaningful feature difference for server and workstation environments where error-correcting memory is critical. The Core i7-940 is a desktop part, and the Xeon X5550 is a server or workstation part, which explains why ECC appears on one but not the other.

Other specifications are shared. Both use Intel Socket 1366, both support PCIe Gen 2, neither has integrated graphics, and neither has an unlocked multiplier. The release dates differ, with the Core i7-940 arriving on November 16, 2008, and the Xeon X5550 following on March 29, 2009. Both are now end-of-life products.

Head-to-Head Benchmarks

The head-to-head results are consistent, so let's walk through the numbers. In Cinebench R15 multicore, the Core i7-940 scores 264 and the Xeon X5550 scores 259. That is a 1.9% win for the desktop chip. The margin is small, but it is repeatable.

Cinebench R20 multicore shows the same pattern. The Core i7-940 hits 1102, while the Xeon X5550 reaches 1083. The delta is 1.8%. This benchmark stresses all eight threads, and the Core i7-940's higher clock speed gives it a persistent edge.

Single-core tests are where the difference narrows. In Cinebench R20 singlecore, the Core i7-940 scores 155 and the Xeon scores 152, a 2% lead. In Cinebench R23 singlecore, the scores are 370 and 364 respectively, a 1.6% gap. The Core i7-940 wins both, but the percentage differences are slightly larger in the R20 singlecore test.

The largest head-to-head margin is 2%, which occurs in Cinebench R20 singlecore. The smallest is 1.6%, in Cinebench R23 singlecore. The multi-core tests all land at 1.8% or 1.9%. This suggests that the clock speed advantage translates fairly uniformly across workload types, with no single benchmark showing a dramatic outlier.

The average benchmark scores in the database reflect this overall picture. The Core i7-940 has an average benchmark score of 903, and the Xeon X5550 sits at 888. That is a 1.7% difference, consistent with the individual test deltas. Both processors land in the 24th percentile of all CPUs in the database, meaning they are in the lower quarter of overall performance, but they are closely matched with each other.

The Verdict

The data is unambiguous. If the only consideration is Cinebench performance, the Intel Core i7-940 is the better processor. It wins all five head-to-head tests, with margins ranging from 1.6% to 2%. The higher base and boost clocks are the likely cause, as the architecture, core count, thread count, and cache are identical between the two.

The Xeon X5550's redeeming feature is ECC memory support. That is not measured in these benchmarks, but it is a real specification difference. For a system that requires error-correcting memory, the Xeon X5550 is the only choice of the two. The Core i7-940 cannot be configured with ECC memory, which rules it out for certain server or workstation workloads.

Both processors share the same 45 nm process, the same 731 million transistor count, and the same 263 mm² die size. They also share the same socket and PCIe generation. The Core i7-940 has a higher TDP at 130 watts, while the Xeon X5550 is more power-efficient at 95 watts. That power difference is worth noting for system builders who care about thermal output or energy consumption.

In terms of nearest rivals, the Core i7-940 matches the Intel Core i5-5350U exactly at an average score of 903, with a 0% delta. The Xeon X5550 matches the Intel Core i3-6100 at 888, also with a 0% delta. These rival comparisons place both processors in similar performance territory, but the Core i7-940 sits slightly higher in the overall rankings.

The verdict, strictly from the recorded data: choose the Core i7-940 for maximum Cinebench performance, choose the Xeon X5550 if ECC memory support is a hard requirement. There is no third option in this data set, and no other differentiating factor appears in the specifications.

FAQ

Q: Which processor is faster in multi-core Cinebench tests?

A: The Intel Core i7-940 wins all three multi-core tests. It leads by 1.9% in Cinebench R15 multicore (264 versus 259), by 1.8% in Cinebench R20 multicore (1102 versus 1083), and by 1.8% in Cinebench R23 multicore (2626 versus 2580).

Q: Does the Xeon X5550 win any benchmark in the head-to-head data?

A: No. The Xeon X5550 records zero wins out of five head-to-head benchmarks. The Core i7-940 wins all five, including both single-core and multi-core tests.

Q: What is the main architectural difference between these two CPUs?

A: Both use the Nehalem architecture on a 45 nm process with 731 million transistors and a 263 mm² die. The key differences are the clock speeds and memory support: the Core i7-940 has a 2.93 GHz base and 3.20 GHz boost, while the Xeon X5550 runs at 2.67 GHz and 3.07 GHz. The Xeon also supports ECC memory, which the Core i7-940 does not.

Q: Are these processors in the same performance percentile?

A: Yes, both are in the 24th percentile of all CPUs in the database. Their average benchmark scores are close: 903 for the Core i7-940 and 888 for the Xeon X5550.

Q: Which CPU has a lower TDP?

A: The Xeon X5550 has a TDP of 95 watts, while the Core i7-940 has a TDP of 130 watts. The Xeon is the more power-efficient part despite being slightly slower in benchmarks.

Q: Do both processors have the same cache configuration?

A: Yes. Both have 64 KB of L1 per core, 256 KB of L2 per core, and 8 MB of shared L3. There is no cache difference between the two.

Specification Differences

The following fields differ between the Intel Core i7-940 and the Intel Xeon X5550:

• Base clock: 2.93 GHz versus 2.67 GHz
• Boost clock: 3.20 GHz versus 3.07 GHz
• TDP: 130 watts versus 95 watts
• Codename: Bloomfield versus Gainestown
• Generation: Core i7 (Bloomfield) versus Xeon (Gainestown)
• ECC memory support: No versus Yes
• Market segment: Desktop versus Server/Workstation
• Release date: November 16, 2008 versus March 29, 2009
• Part number: SLBCK versus SLBF5

All other recorded specifications are identical: 4 cores, 8 threads, Intel Socket 1366, Nehalem architecture, 45 nm process, 731 million transistors, 263 mm² die size, 64 KB L1 per core, 256 KB L2 per core, 8 MB shared L3, DDR3 memory support, triple-channel memory bus, PCIe Gen 2, no integrated graphics, no unlocked multiplier, Intel foundry, and end-of-life production status.