AMD Opteron 3365 vs Intel Core i3-8121U Comparison

Head-to-Head Benchmarks

The recorded data shows a clean sweep for the Intel Core i3-8121U across every shared benchmark, with the AMD Opteron 3365 trailing by a consistent margin of roughly 5% in each test. The largest single victory comes in Cinebench R15 multi-core, where the Intel part scores 366 against 349 for the Opteron, a 4.9% advantage. That same 4.9% delta appears in Cinebench R20 single-core (215 vs. 205) and Cinebench R23 single-core (513 vs. 489), indicating that the Intel chip’s per-thread advantage is remarkably stable across different rendering workloads.

In multi-core tests, the margin narrows slightly but remains decisive. Cinebench R20 multi-core shows the Intel part at 1527 versus the Opteron’s 1457, a 4.8% lead. Cinebench R23 multi-core repeats that pattern: 3637 for Intel, 3470 for AMD, again 4.8% apart. The consistency of these deltas, all falling between 4.8% and 4.9%, suggests the performance gap is architectural rather than workload-specific. The Intel Core i3-8121U wins all five head-to-head benchmarks, giving it a 5-0 record in the database.

It is worth remembering the Opteron 3365 lacks a Cinebench R15 single-core result in the recorded data, so that comparison cannot be made. However, the available single-core tests (R20 and R23) both show the same approximate 4.9% edge for Intel, reinforcing the pattern. The average benchmark score for the Intel chip is 1209, while the Opteron sits at 1194, a difference of about 1.3% in the aggregate. That smaller gap reflects the fact that the Intel part’s benchmark suite includes Geekbench results (2215 multi-core, 1149 single-core) which are not present for the AMD chip, pulling the averages closer together than the head-to-head deltas would suggest.

The Verdict

Based strictly on the measured data, the Intel Core i3-8121U is the faster processor in every comparable workload. It leads the AMD Opteron 3365 by 4.8% to 4.9% across Cinebench R15, R20, and R23 in both single-core and multi-core tests, and it does so with a far lower thermal design power (15 watts versus 65 watts). The database places both processors at the 34th percentile among all CPUs, meaning they are statistically peers in the broader performance distribution, but the head-to-head numbers leave no ambiguity about which one wins in a direct comparison.

The Opteron 3365 compensates with more cores (8 versus 2) and more threads (8 versus 4), yet it still loses every multi-core benchmark. That outcome indicates the Intel chip’s architectural efficiency, built on a 10 nm process, more than offsets the AMD chip’s raw core count. For applications that rely on single-threaded performance, the Intel part is clearly preferred, as its 4.9% lead in both R20 and R23 single-core tests demonstrates. For multi-threaded workloads, the Opteron’s extra cores do not translate into a win, so the Intel part remains the better choice there as well, at least within the recorded benchmarks.

The AMD Opteron 3365 targets the server and workstation segment with its 65-watt envelope and Socket AM3+ platform, while the Intel Core i3-8121U is a mobile part with a 15-watt design. If the selection criteria are performance per watt, the Intel chip wins overwhelmingly. If the criteria are platform compatibility or the need for eight physical cores in a server environment, the Opteron has its place, but the benchmark data does not support a performance-based argument for choosing it over the Intel part.

Architecture Differences

The two processors come from fundamentally different design eras. The Intel Core i3-8121U is built on Cannon Lake architecture with a 10 nm process node, manufactured by Intel itself. The AMD Opteron 3365 uses the K10 architecture, codenamed Delhi, fabricated on a 32 nm process by GlobalFoundries. That process gap, 10 nm versus 32 nm, is the single largest architectural differentiator and explains much of the performance-per-watt disparity.

The Intel chip features 2 cores and 4 threads, with a base clock of 2.20 GHz and a boost clock of 3.20 GHz. Its cache hierarchy is per-core for L1 (64 KB per core) and L2 (256 KB per core), with a shared 4 MB L3 cache. The die size is 70.52 mm². The AMD Opteron 3365, by contrast, packs 8 cores and 8 threads, running at a base clock of 2.30 GHz and a boost clock of 3.30 GHz. Its cache layout is a single 384 KB L1, a 4 MB L2, and an 8 MB shared L3, spread across a much larger 315 mm² die with 1,200 million transistors.

Memory architecture also diverges sharply. The Intel part supports DDR4 memory over a dual-channel bus with a bandwidth of 38.4 GB/s. The AMD part uses DDR3, also dual-channel, but with a lower bandwidth of 29.9 GB/s. Neither chip supports ECC memory, and both have locked multipliers. The Intel chip uses an Intel BGA 1440 socket, while the AMD chip uses AMD Socket AM3+.

PCIe connectivity differs as well. The Intel Core i3-8121U provides PCIe Gen 3 with 16 lanes (CPU only), whereas the AMD Opteron 3365 offers PCIe Gen 2 without a lane count specified in the database. Integrated graphics are absent on the Intel part, while the AMD chip lists "On certain motherboards (Chipset feature)" as its integrated graphics option, meaning it relies on the motherboard chipset rather than the CPU itself.

Specification Differences

| Specification | Intel Core i3-8121U | AMD Opteron 3365 |

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

| Cores | 2 | 8 |

| Threads | 4 | 8 |

| Base Clock | 2.20 GHz | 2.30 GHz |

| Boost Clock | 3.20 GHz | 3.30 GHz |

| TDP | 15 W | 65 W |

| Process Node | 10 nm | 32 nm |

| Foundry | Intel | GlobalFoundries |

| Die Size | 70.52 mm² | 315 mm² |

| Transistors | Not listed | 1,200 million |

| L1 Cache | 64 KB (per core) | 384 KB |

| L2 Cache | 256 KB (per core) | 4 MB |

| L3 Cache | 4 MB (shared) | 8 MB (shared) |

| Memory Support | DDR4 | DDR3 |

| Memory Bandwidth | 38.4 GB/s | 29.9 GB/s |

| PCIe | Gen 3, 16 Lanes (CPU only) | Gen 2 |

| Integrated Graphics | None | On certain motherboards (Chipset feature) |

| Socket | Intel BGA 1440 | AMD Socket AM3+ |

| Market Segment | Mobile | Server/Workstation |

| Part Number | SRCVC | OS3365OLW8KHK |

The clock speeds are close, with the Opteron holding a slight edge in both base (2.30 vs. 2.20 GHz) and boost (3.30 vs. 3.20 GHz). That advantage does not translate into benchmark wins, which points to the Intel architecture’s superior instructions-per-clock on the 10 nm process. The cache distribution reflects the core count difference: the Opteron has more total L1 and L2 cache because it has more cores, but its per-core allocation is smaller. The Intel chip’s 64 KB L1 and 256 KB L2 per core are larger on a per-thread basis, which likely contributes to its single-core performance lead.

FAQ

Q: Which processor has a higher single-core score in Cinebench R23?

A: The Intel Core i3-8121U scores 513, while the AMD Opteron 3365 scores 489, a 4.9% advantage for Intel.

Q: How many cores does the AMD Opteron 3365 have?

A: It has 8 cores and 8 threads, compared to the Intel Core i3-8121U’s 2 cores and 4 threads.

Q: What is the thermal design power of each processor?

A: The Intel Core i3-8121U has a TDP of 15 watts, while the AMD Opteron 3365 has a TDP of 65 watts.

Q: Do either of these processors support ECC memory?

A: No, both the Intel Core i3-8121U and the AMD Opteron 3365 list ECC memory support as false.

Q: Which chip has a higher memory bandwidth?

A: The Intel Core i3-8121U supports DDR4 with a bandwidth of 38.4 GB/s, whereas the AMD Opteron 3365 supports DDR3 with a bandwidth of 29.9 GB/s.

Q: What is the average benchmark score for each processor?

A: The Intel Core i3-8121U has an average benchmark score of 1209, and the AMD Opteron 3365 has an average benchmark score of 1194.

Where Each One Wins

The Intel Core i3-8121U wins every benchmark it shares with the AMD Opteron 3365, so its advantages are straightforward. In single-core workloads, it leads by 4.9% in Cinebench R20 and R23, making it the stronger choice for lightly threaded applications such as legacy software, scripting, or interactive workloads where one or two threads dominate. In multi-core workloads, it leads by 4.8% in Cinebench R20 and R23, and by 4.9% in R15, meaning even when all threads are active, the Intel chip’s efficiency overcomes the Opteron’s 4x core advantage. The Intel part also wins decisively on power efficiency, drawing only 15 watts versus 65 watts, which suits mobile platforms and compact systems.

The AMD Opteron 3365 does not win any benchmark in the head-to-head comparison, but it does offer attributes that matter outside raw performance scores. Its 8 cores and 8 threads provide physical core count that some server or workstation software may expect, even if the benchmarks do not reward it. Its socket (AMD AM3+) and server market segment indicate a platform designed for multi-socket or legacy server environments. The Opteron also has a slightly higher base and boost clock, and it includes integrated graphics via the motherboard chipset, which the Intel part lacks entirely. For users constrained to the AM3+ platform, or those needing eight physical cores for virtualization or parallel workloads that scale beyond the benchmark suite, the Opteron remains a viable option despite losing the recorded tests.