Intel Core i5-2400 vs Intel Xeon E5645 Comparison

The Intel Xeon E5645 and Intel Core i5-2400 are both end-of-life processors from Intel, but they target different segments: the Xeon is a server/workstation part built on Westmere-EP, while the i5 is a desktop chip based on Sandy Bridge. In the database, the Xeon carries an average benchmark score of 1211 against the i5's 1187, placing them at the 34th and 33rd percentiles of all CPUs respectively. The recorded head-to-head results, however, show a clear separation: the Xeon wins all five Cinebench comparisons, with margins between 27.8% and 28%. This article breaks down where each processor wins, how their architectures differ, and what the data says about choosing between them.

Where Each One Wins

The head-to-head benchmark set contains five Cinebench tests, and the Xeon E5645 wins every single one. That includes both multi-core and single-core workloads. In multi-core tests, the Xeon's advantage is substantial: it scores 421 versus 329 in Cinebench R15 multi-core, 1758 versus 1374 in R20 multi-core, and 4187 versus 3272 in R23 multi-core. The margins are consistent, ranging from 27.9% to 28%. The Xeon also wins the single-core tests, which is notable because the i5-2400 has a higher base clock (3.10 GHz versus 2.40 GHz) and a higher boost clock (3.40 GHz versus 2.67 GHz). In Cinebench R20 single-core, the Xeon scores 248 against the i5's 194, a 27.8% lead; in R23 single-core, it scores 591 versus 462, a 27.9% lead.

The i5-2400 does have a few advantages that are not reflected in the head-to-head benchmarks. It includes integrated graphics (Intel HD 2000), which the Xeon lacks entirely. That means the i5 can drive a display without a discrete GPU, a capability that matters for basic desktop systems or low-power builds. The i5 also supports PCIe Gen 3 with 16 CPU lanes, while the Xeon only offers PCIe Gen 2. For workloads that depend on newer PCIe devices, the i5's interface is more modern. However, in pure compute performance as measured by the database, the Xeon is the clear winner across every recorded test. The i5 has no benchmark wins in the head-to-head set, so any use-case split must rely on features outside of raw CPU performance.

Architecture Differences

The two processors come from different architectural generations. The Xeon E5645 is based on Westmere, specifically the Westmere-EP codename, while the i5-2400 uses Sandy Bridge. Both are built on Intel's 32 nm process, and their transistor counts are nearly identical: 1,170 million for the Xeon and 1,160 million for the i5. The die sizes differ slightly, with the Xeon at 239 mm² and the i5 at 216 mm².

The core and thread counts are a major differentiator. The Xeon has 6 cores and 12 threads, while the i5 has 4 cores and 4 threads. This explains the Xeon's dominance in multi-threaded workloads. The cache hierarchy also favors the Xeon: it has 12 MB of shared L3 cache, whereas the i5 has only 6 MB. Both have 64 KB of L1 and 256 KB of L2 per core, but the larger L3 on the Xeon gives it more room for shared data.

Memory support differs as well. The Xeon uses triple-channel DDR3 memory and supports ECC, making it suitable for error-correcting memory in servers or workstations. The i5 uses dual-channel DDR3 and does not support ECC. The Xeon's memory bus is wider, which can benefit memory-intensive applications. The i5, on the other hand, has integrated graphics and a PCIe Gen 3 controller with 16 lanes, while the Xeon's PCIe is Gen 2. The sockets are incompatible: the Xeon uses Intel Socket 1366, the i5 uses Intel Socket 1155.

Power consumption is also different. The Xeon has a TDP of 80 watts, while the i5 is rated at 95 watts. Despite having more cores and threads, the Xeon draws less power, which is a notable efficiency advantage. The base and boost clocks are lower on the Xeon (2.40 GHz and 2.67 GHz) compared to the i5 (3.10 GHz and 3.40 GHz), yet the Xeon still wins single-core tests, indicating that architectural efficiency and cache size play a larger role than raw clock speed in these benchmarks.

The Verdict

Based strictly on the recorded data, the Intel Xeon E5645 is the stronger performer in every head-to-head benchmark. It wins all five Cinebench tests, with margins of roughly 28% in both multi-core and single-core workloads. The Xeon also offers more cores, more threads, more L3 cache, triple-channel memory, ECC support, and a lower TDP. For any workload that relies on CPU compute, the Xeon is the clear choice.

The Intel Core i5-2400, however, has its own merits. It includes integrated graphics, which the Xeon does not, so it can serve as a complete desktop solution without a discrete GPU. It also supports PCIe Gen 3, which may be relevant for modern expansion cards. The i5's higher clock speeds do not translate into benchmark wins, but they could be beneficial in scenarios not covered by the Cinebench suite, such as lightly threaded tasks that are sensitive to clock frequency. Still, the database shows no test where the i5 outperforms the Xeon.

For a server or workstation environment where ECC memory and multi-threaded throughput are priorities, the Xeon E5645 is the obvious pick. For a budget desktop build that needs integrated graphics and a simpler platform, the i5-2400 remains a viable option, but it will lag behind the Xeon in compute-heavy applications. The data does not support any scenario where the i5 wins on performance; its advantages are purely feature-based.

FAQ

Q: Which processor has more cores and threads?

A: The Intel Xeon E5645 has 6 cores and 12 threads, while the Intel Core i5-2400 has 4 cores and 4 threads.

Q: Does the Xeon E5645 support ECC memory?

A: Yes, the Xeon E5645 supports ECC memory. The Core i5-2400 does not.

Q: Which CPU has integrated graphics?

A: Only the Intel Core i5-2400 has integrated graphics (Intel HD 2000). The Xeon E5645 has no integrated graphics.

Q: What are the base and boost clock speeds of each processor?

A: The Xeon E5645 has a base clock of 2.40 GHz and a boost clock of 2.67 GHz. The i5-2400 has a base clock of 3.10 GHz and a boost clock of 3.40 GHz.

Q: How much L3 cache does each CPU have?

A: The Xeon E5645 has 12 MB of shared L3 cache, while the i5-2400 has 6 MB.

Q: Which processor wins in single-core Cinebench R23?

A: The Xeon E5645 wins with a score of 591, compared to the i5-2400's 462, a 27.9% difference.

Head-to-Head Benchmarks

The head-to-head results are entirely one-sided. In Cinebench R15 multi-core, the Xeon E5645 scores 421 against the i5-2400's 329, a 28% lead. The R20 multi-core test shows a similar pattern: 1758 versus 1374, a 27.9% margin. The R23 multi-core test gives the Xeon 4187 and the i5 3272, again a 28% difference. These multi-core results align with the Xeon's 6-core, 12-thread configuration versus the i5's 4-core, 4-thread setup.

The single-core results are more surprising given the clock speed disadvantage. The Xeon's base clock is 2.40 GHz and its boost is 2.67 GHz, while the i5 runs at 3.10 GHz base and 3.40 GHz boost. Yet the Xeon still wins. In Cinebench R20 single-core, the Xeon scores 248 versus 194, a 27.8% advantage. In R23 single-core, it scores 591 versus 462, a 27.9% lead. This suggests that the Xeon's larger L3 cache and Westmere architecture deliver better per-clock performance in these tests, or that the i5's higher clocks are offset by other factors.

The i5-2400 does have additional benchmark scores in the database that are not part of the head-to-head set, including Geekbench multi-core (2011) and single-core (666). However, since there is no corresponding Geekbench result for the Xeon, these cannot be compared directly. The recorded head-to-head data covers only Cinebench, and in every one of those tests, the Xeon E5645 is the winner. The margins are consistent, hovering around 28%, which indicates a stable performance gap across different Cinebench versions and workload types. There is no test in the head-to-head set where the i5-2400 comes out ahead.