Intel Core i7-975 vs Intel Xeon W5580 Comparison

Head-to-Head Benchmarks

The benchmark data shows a clean sweep in favor of the Intel Core i7-975, though the margins are consistently narrow. Across all five recorded Cinebench workloads, the Core i7-975 wins every test, with deltas ranging from 0.6% to 1.2%. This is not a dominant victory, but it is a uniform one.

The largest single advantage appears in two multicore tests. In Cinebench R20 multicore, the Core i7-975 scores 1249 against 1234 for the Xeon W5580, a 1.2% lead. The same 1.2% delta appears in Cinebench R23 multicore, where the Core i7-975 posts 2974 versus 2940. These multicore results suggest that the higher base and boost clocks of the Core i7-975 translate into a consistent, if modest, throughput advantage in heavily threaded workloads.

Single-core performance tells a similar story with smaller margins. In Cinebench R20 single-core, the Core i7-975 scores 175 against 174, a 0.6% delta. In Cinebench R23 single-core, the margin widens slightly to 1%, with scores of 419 and 415. The Cinebench R15 multicore test shows a 1% delta, with 299 versus 296. Every recorded measurement points the same way.

The average benchmark scores reinforce this picture. The Core i7-975 holds an average score of 1023, while the Xeon W5580 sits at 1012. That works out to roughly 1.1% higher average performance for the desktop part. In the context of their respective nearest rivals, both processors land in the same performance bracket. The Core i7-975 is effectively tied with the AMD Ryzen 5 PRO 2500U at 1024, the AMD Phenom II X6 1075T at 1024, the Intel Pentium Gold G5600 at 1022, and the Intel Processor N150 at 1025. The Xeon W5580 matches the Intel Core i7-2675QM at 1012, sits just below the Intel Core i5-2300 at 1014, and slightly above the Intel Core i3-7100H at 1009 and the Intel Processor N100 at 1007.

What this means is that the two processors are functionally equivalent in everyday workload performance, with the Core i7-975 holding a slight edge that is consistent across every test. The data does not show any workload category where the Xeon W5580 pulls ahead.

Architecture Differences

Both processors share the same fundamental Nehalem architecture, but they diverge in several meaningful ways. The Core i7-975 uses the Bloomfield codename, while the Xeon W5580 uses Gainestown. Both are built on a 45 nm process at Intel's foundry, with 731 million transistors and a die size of 263 mm². Both have 4 cores and 8 threads, with 64 KB of L1 cache per core and 256 KB of L2 cache per core. The shared L3 cache is 8 MB in both cases.

Clock speeds are where the Core i7-975 pulls ahead. It has a base clock of 3.33 GHz and a boost clock of 3.60 GHz. The Xeon W5580 runs at 3.20 GHz base and 3.47 GHz boost. These clock differences explain the benchmark deltas, as both processors share the same core and cache configuration, so raw frequency is the primary differentiator in compute-bound tests.

Memory support shows a notable split. Both support DDR3 with triple-channel memory buses, but the memory bandwidth figures differ. The Core i7-975 is rated at 25.6 GB/s, while the Xeon W5580 is rated at 32.0 GB/s. This is a surprising inversion: the server part has higher memory bandwidth, yet it still loses in compute benchmarks. The Xeon W5580 also supports ECC memory, while the Core i7-975 does not. This is a critical feature distinction for workstation and server reliability use cases.

The market positioning differs as expected. The Core i7-975 is a desktop part in the Core i7 Extreme generation, while the Xeon W5580 targets the server and workstation segment. Both use Intel Socket 1366 and PCIe Gen 2. Neither has integrated graphics. The Core i7-975 has an unlocked multiplier, making it open to overclocking, while the Xeon W5580 has a locked multiplier.

Production status is end-of-life for both. The Xeon W5580 was released earlier, on March 29, 2009, while the Core i7-975 followed on June 1, 2009. The part numbers differ as well: SLBEQ for the Core i7-975 and SLBF2 for the Xeon W5580.

FAQ

Q: Which processor is faster in multicore workloads?

A: The Intel Core i7-975 wins every recorded multicore test. In Cinebench R20 multicore, it scores 1249 against 1234 for the Xeon W5580, a 1.2% lead. In Cinebench R23 multicore, it scores 2974 versus 2940, also a 1.2% delta.

Q: Is there any test where the Xeon W5580 wins?

A: No. Across all five recorded benchmarks, the Core i7-975 wins every test. The Xeon W5580 records zero wins in the head-to-head data.

Q: How do the clock speeds compare?

A: The Core i7-975 has a base clock of 3.33 GHz and a boost clock of 3.60 GHz. The Xeon W5580 has a base clock of 3.20 GHz and a boost clock of 3.47 GHz. The Core i7-975 is higher in both metrics.

Q: Do these processors support ECC memory?

A: Only the Xeon W5580 supports ECC memory. The Core i7-975 does not. This is a significant feature for memory reliability in server or workstation environments.

Q: What is the memory bandwidth difference?

A: The Xeon W5580 has a higher rated memory bandwidth of 32.0 GB/s, while the Core i7-975 is rated at 25.6 GB/s. Both use triple-channel DDR3 memory support.

Q: Are these processors overclockable?

A: The Core i7-975 has an unlocked multiplier, so it is open to overclocking. The Xeon W5580 has a locked multiplier, which prevents multiplier-based overclocking.

Q: How do these processors compare to their nearest rivals in the database?

A: The Core i7-975 has an average score of 1023, matching the AMD Ryzen 5 PRO 2500U and AMD Phenom II X6 1075T at 1024, and the Intel Pentium Gold G5600 at 1022. The Xeon W5580 has an average score of 1012, matching the Intel Core i7-2675QM and sitting between the Intel Core i5-2300 at 1014 and the Intel Core i3-7100H at 1009.

The Verdict

The data points to a clear, if narrow, choice for most users. The Intel Core i7-975 outperforms the Xeon W5580 in every recorded benchmark, with average scores of 1023 versus 1012. If raw compute performance is the sole criterion, the Core i7-975 is the better pick. Its higher base and boost clocks deliver consistent advantages across single-core and multicore workloads, and its unlocked multiplier adds flexibility for overclocking.

The Xeon W5580, however, offers features that the Core i7-975 cannot match. ECC memory support is a meaningful differentiator for systems where data integrity is critical. The higher memory bandwidth rating of 32.0 GB/s versus 25.6 GB/s suggests the server part is better suited for memory-intensive workloads, even though the benchmark data does not capture that advantage in Cinebench tests.

For a desktop user seeking maximum compute performance in the same socket generation, the Core i7-975 is the logical choice. For a workstation or server builder prioritizing ECC memory and memory bandwidth, the Xeon W5580 justifies its position despite the slight benchmark deficit. The performance gap is small enough that the feature set should drive the decision. Both processors sit at the 28th percentile among all CPUs in the database, so neither is a performance outlier today.

Specification Differences

| Field | Intel Core i7-975 | Intel Xeon W5580 |

| --- | --- | --- |

| Base Clock | 3.33 GHz | 3.20 GHz |

| Boost Clock | 3.60 GHz | 3.47 GHz |

| Codename | Bloomfield | Gainestown |

| Generation | Core i7 Extreme (Bloomfield) | Xeon (Gainestown) |

| Memory Bandwidth | 25.6 GB/s | 32.0 GB/s |

| ECC Memory | No | Yes |

| Market Segment | Desktop | Server/Workstation |

| Launch MSRP | $1059 | $1600 |

| Multiplier Unlocked | Yes | No |

| Part Number | SLBEQ | SLBF2 |

| Release Date | 2009-06-01 | 2009-03-29 |

The two processors share the same core count, thread count, cache configuration, process node, transistor count, die size, socket, PCIe generation, and TDP of 130 W. The differences are concentrated in clock speeds, memory features, and market positioning. The Core i7-975 is the faster part in benchmark terms, while the Xeon W5580 brings ECC support and higher memory bandwidth to the table.