CPU Comparison

The Intel Xeon E5540 and Intel Core i7-870S are both 45 nm Nehalem-era parts with four cores and eight threads, but they target different segments: the Xeon is a server/workstation chip on Socket 1366, while the i7-870S is a desktop processor on Socket 1156. Benchmark data shows the Xeon E5540 edges out the i7-870S in every tested workload, but the margins are remarkably slim, never exceeding 1.7%. Both processors sit at the 22nd percentile of all CPUs, indicating they occupy the same performance tier despite their different market positioning.

Head-to-Head Benchmarks

The Xeon E5540 wins all five head-to-head Cinebench comparisons, but the victories are narrow. In Cinebench R15 multicore, the Xeon scores 240 against the i7-870S’s 236, a 1.7% advantage, the largest gap in any test. The R20 multicore test shows a similar pattern: 1001 for the Xeon versus 987 for the i7, a 1.4% lead. Single-core results follow the same trend, with the Xeon posting 141 in R20 single-core against 139 for the i7-870S, again a 1.4% difference. The R23 multicore run gives the Xeon 2384 versus 2350, while R23 single-core shows 336 versus 331, both yielding roughly 1.4–1.5% margins.

These numbers tell a clear story: the Xeon E5540 is consistently faster, but the performance gap is almost negligible in real-world terms. A 1.7% lead in R15 multicore translates to about four points, well within run-to-run variance for most workloads. The i7-870S does hold a meaningful advantage in boost clock (3.60 GHz versus 2.80 GHz), yet that higher frequency does not translate into a win in any benchmark, likely because the Xeon’s triple-channel memory configuration provides a compensating bandwidth advantage. The average benchmark scores reinforce this: the Xeon averages 820 across all tests, while the i7-870S averages 809, a 1.4% overall difference that mirrors the individual Cinebench results.

Looking at the nearest rivals for each chip, the Xeon E5540’s average score of 820 sits just above the AMD PRO A10-8750B (821, -0.1%), the Intel Core i5-L16G7 (816, 0.5%), and the Intel Xeon X3440 (815, 0.6%). The i7-870S’s 809 average matches the AMD A10-6800K exactly (0% delta), while trailing the Intel Core 2 Extreme QX9775 (813, -0.5%). In essence, both processors are bracketed by a cluster of similar-performing parts, with the Xeon holding a slight edge over its own rivals that the i7-870S does not always match.

FAQ

Q: Which processor is faster in multi-threaded workloads?

A: The Intel Xeon E5540 wins all multi-core benchmarks. In Cinebench R15 multicore, it scores 240 versus 236 for the i7-870S (1.7% ahead). R20 multicore shows 1001 versus 987 (1.4% ahead), and R23 multicore gives 2384 versus 2350 (1.4% ahead).

Q: Does the i7-870S’s higher boost clock help it win any single-core tests?

A: No. Despite a boost clock of 3.60 GHz compared with 2.80 GHz for the Xeon, the i7-870S loses both single-core benchmarks. The Xeon scores 141 in R20 single-core versus 139, and 336 in R23 single-core versus 331, with deltas of 1.4% and 1.5% respectively.

Q: How do these processors compare to their closest rivals?

A: The Xeon E5540’s average score of 820 is nearly identical to the AMD PRO A10-8750B (821, -0.1%) and slightly above the Intel Core i5-L16G7 (816, 0.5%). The i7-870S’s 809 average exactly matches the AMD A10-6800K (0% delta) and is 0.4% ahead of the AMD Athlon X4 850.

Q: What is the memory configuration difference?

A: The Xeon E5540 supports triple-channel DDR3 with a memory bandwidth of 25.6 GB/s, while the i7-870S uses dual-channel DDR3 with no listed bandwidth figure. The Xeon also supports ECC memory, which the i7-870S does not.

Q: Which processor has the higher thermal design power?

A: The i7-870S has a TDP of 82 watts, slightly higher than the Xeon E5540’s 80 watts. This is notable because the i7-870S achieves a higher boost clock (3.60 GHz versus 2.80 GHz) within a similar power envelope.

Q: Were there any benchmarks where the i7-870S won?

A: No. The head-to-head data shows the Xeon E5540 winning all five tests (winsA: 5, winsB: 0). The i7-870S’s closest result is a 1.4% deficit in R20 multicore and R20 single-core.

Where Each One Wins

The Xeon E5540 wins in every measured benchmark, so its territory is clear: any workload captured by Cinebench R15, R20, or R23, whether single-threaded or multi-threaded. The largest margin comes in R15 multicore, where the 1.7% lead suggests the Xeon’s triple-channel memory interface provides a slight edge in memory-sensitive tasks. The Xeon also wins on platform features: it supports ECC memory and has a higher memory bandwidth rating of 25.6 GB/s, making it the better choice for error-correcting workloads or memory-bandwidth-bound server applications. Its socket (1366) and server/workstation market segment imply a platform designed for longevity and reliability rather than peak consumer performance.

The i7-870S, despite losing every benchmark, still has arguments in its favor. Its boost clock of 3.60 GHz is substantially higher than the Xeon’s 2.80 GHz, which could benefit lightly-threaded applications that are not captured by the Cinebench suite. The i7-870S uses Socket 1156, a mainstream desktop platform, and its dual-channel memory configuration is simpler and potentially cheaper to populate. It also has a slightly higher TDP (82 watts versus 80 watts), suggesting it uses its power budget for clock speed rather than memory bandwidth. For a desktop user running older software that favors high single-core frequency over memory throughput, the i7-870S might feel more responsive in everyday tasks, even if the synthetic benchmarks favor the Xeon.

The average benchmark scores tell a similar story: the Xeon’s 820 average is only 11 points higher than the i7-870S’s 809. This means that in mixed workloads, some multi-threaded, some single-threaded, the difference will be imperceptible. The Xeon’s wins are consistent but tiny, so the decision between these two comes down to platform needs (ECC, memory channels, socket) rather than raw performance.

Specification Differences

The two processors differ in several key specifications. The Xeon E5540 has a base clock of 2.53 GHz and a boost clock of 2.80 GHz, while the i7-870S has a base clock of 2.67 GHz and a boost clock of 3.60 GHz. The i7-870S is therefore faster in both clock states, with a 0.80 GHz advantage in boost. The Xeon uses Socket 1366, while the i7-870S uses Socket 1156. Memory support differs significantly: the Xeon uses triple-channel DDR3 with a bandwidth of 25.6 GB/s and supports ECC memory, while the i7-870S uses dual-channel DDR3 with no listed bandwidth and no ECC support. The PCIe configuration also varies, the Xeon lists "Gen 2" while the i7-870S specifies "Gen 2, 16 Lanes(CPU only)." Transistor counts differ: the Xeon has 731 million transistors on a 263 mm² die, while the i7-870S has 774 million transistors on a 296 mm² die. The TDP is close but not identical: 80 watts for the Xeon versus 82 watts for the i7-870S. Finally, the launch MSRP is $774 for the Xeon, while the i7-870S has no listed launch MSRP in the data.

Architecture Differences

Both processors are built on Intel’s Nehalem architecture using a 45 nm process, but they come from different codenames and generations. The Xeon E5540 uses the Gainestown codename and is listed as "Xeon (Gainestown)" while the i7-870S uses the Lynnfield codename and is listed as "Core i7 (Lynnfield)". This explains the socket difference: Gainestown targets the server-oriented Socket 1366 platform, while Lynnfield is the desktop-oriented Socket 1156 design. The core count is identical (4 cores, 8 threads), and both have the same cache hierarchy: 64 KB L1 per core, 256 KB L2 per core, and 8 MB shared L3. However, the i7-870S has a larger physical implementation, 774 million transistors on a 296 mm² die versus 731 million on 263 mm² for the Xeon. This size increase likely reflects the integrated memory controller and PCIe lanes required for the Socket 1156 desktop platform, which differs from the Xeon’s server-oriented triple-channel memory controller. The i7-870S’s higher boost clock (3.60 GHz versus 2.80 GHz) and slightly higher TDP (82 versus 80 watts) indicate that Intel tuned the Lynnfield design for higher clock speeds, while the Gainestown Xeon focuses on memory bandwidth and ECC support. Both processors lack integrated graphics, are end-of-life, and have locked multipliers. The Xeon’s market segment is "Server/Workstation" while the i7-870S is a "Desktop" part, which aligns with the memory and socket differences. Performance-wise, the architecture differences do not produce a clear winner, the Xeon wins all benchmarks, but the margins are small enough to suggest that the triple-channel memory interface provides a slight edge over the i7-870S’s dual-channel setup, despite the i7-870S’s higher clocks.