CPU Comparison
Intel Core i7-975
Xeon E5620
PERFORMANCE BENCHMARKS
Analysis: Intel Core i7-975 vs Intel Xeon E5620
The Intel Xeon E5620 and Intel Core i7-975 are both legacy Socket 1366 processors, but they target different segments of the market. The Xeon E5620 is a server/workstation part built on the Westmere architecture, while the Core i7-975 is an unlocked desktop Extreme Edition chip from the older Nehalem generation. Despite their differences in clock speed, process node, and market positioning, benchmark data shows they deliver nearly identical performance in the Cinebench suite.
FAQ
Q: Which processor has a higher boost clock speed?
A: The Intel Core i7-975 has a higher boost clock of 3.60 GHz compared to the Intel Xeon E5620’s 2.67 GHz. However, this clock advantage does not translate into a benchmark win, as the Xeon E5620 wins all five head-to-head Cinebench tests.
Q: How do the two compare in multi-core Cinebench R23 performance?
A: The Intel Xeon E5620 scores 2989 in Cinebench R23 multi-core, while the Intel Core i7-975 scores 2974. This gives the Xeon a 0.5% lead. The margin is small, but the Xeon wins consistently across all tested loads.
Q: Do both processors support ECC memory?
A: No. The Intel Xeon E5620 supports ECC memory, a feature typical for server and workstation platforms. The Intel Core i7-975 does not support ECC memory, reflecting its desktop-oriented design.
Q: What is the average benchmark score for each processor?
A: The Intel Xeon E5620 has an average benchmark score of 1029, placing it in the 28th percentile of all CPUs. The Intel Core i7-975 has an average score of 1023, also in the 28th percentile. Their nearest rivals include the AMD Ryzen Embedded V1202B and Intel Pentium G4560, each within 0.3% of the Xeon’s score.
Q: Which processor has a larger L3 cache?
A: The Intel Xeon E5620 has 12 MB of shared L3 cache, while the Intel Core i7-975 has 8 MB of shared L3 cache. The Xeon’s larger cache is a key architectural difference, though it does not produce a substantial performance gap in these benchmarks.
Q: Is the Intel Core i7-975 multiplier unlocked?
A: Yes, the Intel Core i7-975 has an unlocked multiplier, making it suitable for overclocking. The Intel Xeon E5620 has a locked multiplier, which is typical for server processors.
Architecture Differences
The two CPUs come from different architectural generations. The Intel Xeon E5620 is built on the Westmere microarchitecture, specifically the Westmere-EP die, while the Intel Core i7-975 uses the older Nehalem architecture with the Bloomfield die. This generational split is visible in the process node: the Xeon E5620 uses a 32 nm process, whereas the Core i7-975 uses a larger 45 nm process. The Xeon also packs 1,170 million transistors into a 239 mm² die, compared to the Core i7-975’s 731 million transistors on a 263 mm² die.
Both processors have 4 cores and 8 threads, and both feature 64 KB of L1 cache and 256 KB of L2 cache per core. The shared L3 cache differs significantly: the Xeon E5620 offers 12 MB, while the Core i7-975 offers 8 MB. Memory support is similar in that both use DDR3 with a triple-channel memory bus, but the Core i7-975 has a specified memory bandwidth of 25.6 GB/s, while the Xeon E5620 does not list a bandwidth figure in the data. The Xeon E5620 supports ECC memory, a feature absent on the Core i7-975.
Both chips use PCIe Gen 2 and have no integrated graphics. The Xeon E5620 is marked for the Server/Workstation segment, while the Core i7-975 is a Desktop part. The Core i7-975 is the only one with an unlocked multiplier, and it carries the Extreme Edition label. The Xeon E5620 was released on 2010-03-15, while the Core i7-975 launched earlier on 2009-06-01. Both are end-of-life products.
Head-to-Head Benchmarks
The data shows a clean sweep for the Intel Xeon E5620, which wins all five head-to-head Cinebench comparisons, though by very narrow margins. The largest win comes in Cinebench R20 single-core, where the Xeon scores 177 against the Core i7-975’s 175, a 1.1% lead. This is notable because the Core i7-975 has a significantly higher boost clock of 3.60 GHz versus 2.67 GHz, yet it still trails in single-threaded performance. The Xeon’s newer Westmere architecture and larger 12 MB L3 cache likely offset the clock deficit.
In multi-core workloads, the results are similarly tight. In Cinebench R15 multi-core, the Xeon E5620 scores 301, edging out the Core i7-975’s 299 with a 0.7% delta. The Cinebench R20 multi-core test shows the Xeon at 1255 versus the Core i7-975 at 1249, a 0.5% difference. The Cinebench R23 multi-core test follows the same pattern: the Xeon scores 2989, the Core i7-975 scores 2974, again a 0.5% margin.
The single-core results in Cinebench R23 show the Xeon E5620 at 422 and the Core i7-975 at 419, a 0.7% advantage for the Xeon. Even in the test where the Core i7-975 should theoretically excel due to its higher clocks, the Xeon maintains a lead. The overall average benchmark scores reflect this parity: the Xeon E5620 averages 1029, while the Core i7-975 averages 1023. Both sit in the 28th percentile of all CPUs, and their nearest rivals, the AMD Ryzen Embedded V1202B, Intel Pentium G4560, Intel Core i7-5650U, and Intel Core i3-4340, are all within 0.3% of the Xeon’s score. The data indicates that architectural efficiency, not raw clock speed, defines the outcome here.
Specification Differences
The Intel Xeon E5620 and Intel Core i7-975 differ in several key specifications. The base clock differs substantially: the Xeon runs at 2.40 GHz, while the Core i7-975 runs at 3.33 GHz. The boost clocks are 2.67 GHz and 3.60 GHz, respectively. Thermal design power (TDP) also diverges, with the Xeon rated at 80 watts and the Core i7-975 at 130 watts.
The process node and die details are distinct: the Xeon E5620 uses a 32 nm process with 1,170 million transistors on a 239 mm² die, while the Core i7-975 uses a 45 nm process with 731 million transistors on a 263 mm² die. The L3 cache is larger on the Xeon at 12 MB shared, versus 8 MB shared on the Core i7-975. The Xeon supports ECC memory, which the Core i7-975 does not.
Memory bandwidth is listed for the Core i7-975 at 25.6 GB/s, but no such figure is provided for the Xeon E5620. The market segments differ: the Xeon is a Server/Workstation part, while the Core i7-975 is a Desktop part. The multiplier is unlocked on the Core i7-975 but locked on the Xeon. The release dates differ, with the Xeon launching on 2010-03-15 and the Core i7-975 on 2009-06-01. The Core i7-975 has a launch MSRP of $1059, while the Xeon E5620 has no listed launch MSRP. The part numbers are SLBV4 for the Xeon and SLBEQ for the Core i7-975.
The Verdict
The benchmark data is unambiguous: the Intel Xeon E5620 outperforms the Intel Core i7-975 in every tested workload, despite the Core i7-975’s higher clock speeds. The Xeon E5620 leads by 0.7% in Cinebench R15 multi-core, 0.5% in Cinebench R20 multi-core, 1.1% in Cinebench R20 single-core, 0.5% in Cinebench R23 multi-core, and 0.7% in Cinebench R23 single-core. With a perfect 5-0 record in head-to-head tests, the Xeon is the better performer in this comparison.
The Core i7-975 offers a higher base clock of 3.33 GHz and a higher boost clock of 3.60 GHz, along with an unlocked multiplier for overclocking potential. It also has a lower transistor count and a smaller L3 cache. However, these advantages do not materialize in the Cinebench results. The Xeon E5620’s 32 nm process and 12 MB L3 cache appear to compensate for the clock deficit, delivering superior results in both single-core and multi-core tests.
For users prioritizing ECC memory support and server-grade reliability, the Xeon E5620 is the clear choice. It also consumes less power, with an 80-watt TDP versus 130 watts for the Core i7-975. For desktop enthusiasts who value an unlocked multiplier, the Core i7-975 offers overclocking flexibility, but the data shows it loses outright in stock performance. The average benchmark scores, 1029 for the Xeon and 1023 for the Core i7-975, confirm that the Xeon is the stronger chip. Based strictly on the numbers, the Intel Xeon E5620 is the recommended pick for raw performance and efficiency, while the Core i7-975 only makes sense for those specifically seeking an unlocked desktop Extreme Edition processor.