CPU Comparison

The Intel Atom C5315 and Intel Xeon W3520 are both four-core server/ workstation processors, but they represent opposite ends of Intel’s design philosophy across a thirteen-year gap. The Atom C5315, a 2022 Parker Ridge part built on 10 nm, edges out the 2009 Bloomfield-based Xeon W3520 in every single benchmark recorded, yet the margins are remarkably thin. The data shows a processor that wins through efficiency and modern instructions rather than raw throughput, while the Xeon relies on higher clocks and hyper-threading to stay competitive.

Where Each One Wins

The head-to-head benchmark sweep is entirely one-sided in favor of the Intel Atom C5315, which takes all five recorded wins. However, the nature of those wins reveals a nuanced picture. The Atom’s victories are narrow, ranging from a 0.7% margin in Cinebench R20 single-core to a 1.2% margin in Cinebench R15 multi-core. This suggests the Atom does not dominate through overwhelming performance but rather through consistent, small advantages across both single-threaded and multi-threaded workloads.

For single-threaded tasks, the Atom C5315 holds a slight edge, winning Cinebench R20 single-core with a score of 149 against the Xeon’s 148, and Cinebench R23 single-core at 357 versus 353. These are sub-1% differences, meaning the Xeon W3520’s higher base clock of 2.67 GHz and boost clock of 2.93 GHz are nearly enough to overcome the Atom’s architectural advantages, but not quite. The Xeon’s 2.93 GHz boost is its best weapon, yet it falls short by a hair in both single-core tests.

Multi-threaded performance tells a similar story. The Xeon W3520 has double the threads (8 versus 4) thanks to hyper-threading, which should give it a significant advantage in heavily parallel workloads. Despite this, the Atom C5315 wins Cinebench R15 multi-core 255 to 252, Cinebench R20 multi-core 1063 to 1052, and Cinebench R23 multi-core 2533 to 2505. The Atom’s wins here are more impressive because it achieves them with half the threads, indicating that its per-core efficiency is substantially higher. The Xeon’s best chance would be in a workload that scales perfectly with thread count, but the data shows the Atom’s 10 nm architecture and newer instruction set compensate for the thread deficit.

Neither processor is a performance powerhouse in absolute terms. The Atom C5315 sits at the 23rd percentile of all CPUs, and the Xeon W3520 matches that exact 23rd percentile. Their average benchmark scores are close: 871 for the Atom and 862 for the Xeon. The Atom’s nearest rival in overall average score is the AMD Athlon PRO 3045B at 872 (a -0.1% delta), while the Xeon’s closest competitor is the Intel Core i5-3470T at 863 (-0.1% delta). Both processors are firmly in entry-level territory, but the Atom achieves parity with a fraction of the power draw.

Architecture Differences

The architectural gap between these two parts is vast. The Atom C5315 uses the Tremont microarchitecture under the Parker Ridge codename, manufactured on Intel’s 10 nm process. The Xeon W3520 uses the Nehalem architecture under the Bloomfield codename, built on Intel’s 45 nm process. This process node difference, 10 nm versus 45 nm, is the single largest factor separating the two, explaining why the Atom can match the Xeon’s performance while consuming only 38 watts against the Xeon’s 130 watts.

The Atom C5315 is a 4-core, 4-thread design with no boost clock, running at a fixed 2.40 GHz. Its cache hierarchy is unusual: 64 KB of L1 per core and 4.5 MB of L2 per module, with no L3 cache. The Xeon W3520 also has 64 KB of L1 per core but uses 256 KB of L2 per core and adds 8 MB of shared L3 cache. The Xeon’s larger L2 allocation per core and shared L3 should help in cache-sensitive workloads, yet the benchmark results do not show a corresponding advantage.

Memory architecture differs significantly. The Atom supports DDR4 memory on a dual-channel bus with a peak bandwidth of 38.4 GB/s. The Xeon supports DDR3 on a triple-channel bus, though its memory bandwidth figure is not recorded in the data. The Atom’s DDR4 support and higher bandwidth are notable advantages, especially for memory-bound server tasks. Both processors support ECC memory, which is expected for server/workstation parts.

PCIe support also diverges. The Atom offers PCIe Gen 3 with 8 lanes (CPU only), while the Xeon provides PCIe Gen 2. The newer PCIe generation on the Atom doubles the per-lane bandwidth, though the Xeon’s platform may have offered more total lanes in its original configuration. Neither processor includes integrated graphics; the Atom lists “N/A” while the Xeon has no graphics field recorded.

The Xeon W3520 contains 731 million transistors on a 263 mm² die, reflecting the complexity of the Nehalem design. The Atom’s transistor count and die size are not recorded, but given the 10 nm process and Tremont architecture, the die is likely far smaller. The Xeon’s end-of-life production status contrasts with the Atom’s active status, and the Xeon’s 2009 release date predates the Atom’s 2022 release by over a decade.

Head-to-Head Benchmarks

The benchmark results are remarkably consistent in their narrow margins. In Cinebench R15 multi-core, the Atom C5315 scores 255 against the Xeon W3520’s 252, a 1.2% delta. This is the largest relative win for the Atom across all tests. In Cinebench R20 multi-core, the Atom scores 1063 versus 1052, a 1.0% delta. The Cinebench R23 multi-core test shows the Atom at 2533 against 2505, a 1.1% delta.

Single-core results follow the same pattern. Cinebench R20 single-core has the Atom at 149 and the Xeon at 148, a 0.7% delta, the closest margin of any test. Cinebench R23 single-core shows the Atom at 357 and the Xeon at 353, a 1.1% delta. In every case, the Atom wins, but the margins are so small they could be considered within run-to-run variance for many workloads.

The significance of these results lies in the context. The Xeon W3520 has a 0.27 GHz base clock advantage and a 0.53 GHz boost clock advantage over the Atom’s fixed 2.40 GHz. The Xeon also has twice the threads. Despite both advantages, the Xeon loses every test. This indicates that the Atom’s Tremont cores are vastly more efficient on a per-clock and per-thread basis. The Atom’s 10 nm process likely allows for higher instruction-level parallelism and better branch prediction, compensating for its lower clock speed.

The 1.2% win in Cinebench R15 multi-core is the Atom’s best result, which is counterintuitive given that R15 is an older benchmark that might favor the older Nehalem architecture. Instead, the Atom’s advantage appears consistent across workload generations, suggesting the Tremont architecture is genuinely superior on a per-core basis. The Xeon’s hyper-threading does not rescue it; the Atom’s 4 physical cores outpace the Xeon’s 4 physical cores plus 4 logical threads.

Specification Differences

| Specification | Intel Atom C5315 | Intel Xeon W3520 |

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

| Cores | 4 | 4 |

| Threads | 4 | 8 |

| Base Clock | 2.40 GHz | 2.67 GHz |

| Boost Clock | None | 2.93 GHz |

| TDP | 38 W | 130 W |

| Socket | Intel BGA 2106 | Intel Socket 1366 |

| Codename | Parker Ridge | Bloomfield |

| Architecture | Tremont | Nehalem |

| Process Node | 10 nm | 45 nm |

| Transistors | Not recorded | 731 million |

| Die Size | Not recorded | 263 mm² |

| L1 Cache | 64 KB (per core) | 64 KB (per core) |

| L2 Cache | 4.5 MB (per module) | 256 KB (per core) |

| L3 Cache | None | 8 MB (shared) |

| Memory Support | DDR4 | DDR3 |

| Memory Bus | Dual-channel | Triple-channel |

| Memory Bandwidth | 38.4 GB/s | Not recorded |

| ECC Memory | Yes | Yes |

| PCIe | Gen 3, 8 Lanes (CPU only) | Gen 2 |

| Integrated Graphics | N/A | Not recorded |

| Production Status | Active | End-of-life |

| Release Date | 2022-06-05 | 2009-03-29 |

| Launch MSRP | $213 | Not recorded |

| Part Number | SRL3Y | SLBEW |

The specification table highlights the fundamental trade-off between the two designs. The Xeon W3520 offers higher clocks, more threads, and a larger cache hierarchy, but it pays for these features with a 130 W TDP and a 45 nm process. The Atom C5315 counters with a drastically lower 38 W TDP, newer DDR4 memory support, and PCIe Gen 3, while matching the Xeon’s core count and ECC capability.

The absence of a boost clock on the Atom is notable; it runs at a constant 2.40 GHz, which simplifies power management but leaves no headroom for burst workloads. The Xeon’s 2.93 GHz boost provides that headroom, but the data shows it is insufficient to overcome the Atom’s architectural efficiency. The Atom’s L2 cache configuration of 4.5 MB per module is unusual and likely reflects a design where modules share cache resources differently than the Xeon’s per-core allocation.

FAQ

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

A: The Intel Atom C5315 wins all three multi-core Cinebench tests: R15 (255 vs 252), R20 (1063 vs 1052), and R23 (2533 vs 2505). Despite having only 4 threads versus the Xeon W3520’s 8 threads, the Atom edges out a win in each case with margins between 1.0% and 1.2%.

Q: How does the Xeon W3520’s higher clock speed affect performance?

A: The Xeon W3520 runs at a base clock of 2.67 GHz with a boost clock of 2.93 GHz, compared to the Atom’s fixed 2.40 GHz. However, the benchmark data shows the Xeon still loses every head-to-head test, indicating the clock advantage is not enough to overcome the Atom’s architectural superiority.

Q: Do both processors support ECC memory?

A: Yes, both the Intel Atom C5315 and the Intel Xeon W3520 support ECC memory. This makes both suitable for server and workstation environments where data integrity is critical.

Q: What is the TDP difference between the two?

A: The Atom C5315 has a TDP of 38 watts, while the Xeon W3520 has a TDP of 130 watts. The Atom achieves nearly identical benchmark scores at roughly one-third the power draw, highlighting the efficiency gains from the 10 nm process versus the 45 nm process.

Q: Which processor has better memory bandwidth?

A: The Atom C5315 supports DDR4 memory on a dual-channel bus with a recorded peak bandwidth of 38.4 GB/s. The Xeon W3520 supports DDR3 on a triple-channel bus, but its memory bandwidth figure is not recorded in the data, so a direct comparison cannot be made.

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

A: The Atom C5315 has an average benchmark score of 871, placing it just behind the AMD Athlon PRO 3045B (872, -0.1% delta) and ahead of the Intel Core i7-3540M (867, 0.5% delta). The Xeon W3520 scores 862, nearly matching the Intel Core i5-3470T (863, -0.1% delta) and trailing the Intel Xeon X3460 (866, -0.5% delta).