AMD Opteron 6238 vs Intel Xeon D-1521 Comparison

Two server processors separated by four years of process technology land in a statistical dead heat, and that is what makes the Opteron 6238 versus Xeon D-1521 comparison so intriguing. The database records the AMD Opteron 6238, a 12-core Interlagos part built on GlobalFoundries' 32 nm node, winning all six recorded benchmark tests against the Intel Xeon D-1521, a 4-core, 8-thread Broadwell design on Intel's 14 nm process. Yet the margins are tiny, roughly one percent in every test, and both chips sit at the 36th percentile of all CPUs in the database with average benchmark scores of 1383 and 1367. A twelve-core server chip barely edging out a low-power four-core part raises the obvious question: which one actually delivers more useful capability?

Head-to-Head Benchmarks

The Opteron 6238 sweeps the board, but the sweep is narrow. In Cinebench R15 multi-core it scores 481 against 476, a 1.1 percent gap. Cinebench R20 multi-core goes 2008 to 1985, again 1.2 percent in AMD's favor. The R23 multi-core result repeats the pattern: 4781 versus 4728, a 1.1 percent win.

Single-core results tell the same story. The R15 single-core test is a perfect tie at 67 points on both chips. R20 single-core reads 283 to 280, a 1.1 percent edge for the Opteron, and R23 single-core lands at 675 versus 667, 1.2 percent apart. That final margin is the largest recorded difference anywhere in the head-to-head data.

Six wins from six tests suggests dominance, but the data says otherwise. A uniform one percent gap across every workload, single- and multi-threaded alike, is indistinguishable from noise in practice. The curious detail is the multi-core result itself: the Opteron has 12 cores and the Xeon has 4 cores with 8 threads, yet the multi-core scores are nearly identical. Twelve Bulldozer cores produce the same rendering throughput as four Broadwell cores running eight threads. The Xeon is clearly extracting far more work per core, which the aggregate scores hide.

Context from the rivals list reinforces how close these two are. The Opteron's average score of 1383 sits within a fraction of a percent of the Intel Core i7-3615QE (1381), Intel Core i3-9100TE (1386), AMD Opteron 6366 HE (1379), and AMD Opteron 6274 (1387). The Xeon D-1521's 1367 is similarly bracketed by the Intel Core i7-3820QM (1366), Intel Xeon E5-1410 v2 (1368), AMD Opteron 6376 (1370), and Intel Core i7-2600 (1370). Both chips occupy the same exact performance neighborhood.

Architecture Differences

The architectural contrast is stark. The Opteron 6238 belongs to AMD's Bulldozer family, codenamed Interlagos, manufactured on a 32 nm GlobalFoundries process. It packs 2,400 million transistors across two dies of 315 mm² each and uses the AMD Socket G34. The Xeon D-1521 is a Broadwell-DE design on Intel's 14 nm node, with 3,200 million transistors on a single 246 mm² die, soldered into an Intel BGA 1667 package.

Core topology diverges completely. AMD's approach is 12 cores and 12 threads organized into modules, each with 2 MB of L2 cache, alongside 8 MB of L3 per die and 768 KB of L1. Intel's approach is 4 cores and 8 threads through hyper-threading, with 64 KB of L1 per core, 256 KB of L2 per core, and 1.5 MB of L3 per core. Clocks favor AMD on paper: 2.60 GHz base and 3.20 GHz boost against Intel's 2.40 GHz base and 2.70 GHz boost.

Memory subsystems point in different directions too. The Opteron uses quad-channel DDR3 with a recorded bandwidth of 51.2 GB/s. The Xeon D-1521 supports both DDR3 and DDR4, but only dual-channel, with no bandwidth figure recorded in the database. Both chips support ECC memory, as expected for Server/Workstation parts. PCIe differs meaningfully: the Opteron offers Gen 2, while the Xeon provides Gen 3 with 24 lanes from the CPU, a clear I/O advantage for the newer chip.

Power draw is the other great divide. The Opteron carries a 115 W TDP; the Xeon D-1521 runs at 45 W. Neither chip has integrated graphics, both have locked multipliers, and the two part numbers are OS6238WKTCGGU and SR2DF respectively. Production status differs as well: the Opteron is end-of-life after launching on November 13, 2011, while the Xeon D-1521 remains active following its October 31, 2015 launch.

FAQ

Q: Which CPU is faster in benchmarks?

A: The AMD Opteron 6238 wins all six recorded Cinebench tests, but every margin is between zero and 1.2 percent. The practical difference is negligible.

Q: How can 4 cores match 12 cores in multi-core scores?

A: The data shows the Xeon D-1521's 4 cores and 8 threads scoring 476 in Cinebench R15 multi-core against the Opteron's 481 with 12 cores. The Broadwell architecture's much higher per-core efficiency offsets the massive core-count disadvantage.

Q: Is single-core performance different between them?

A: Barely. Cinebench R15 single-core is an exact tie at 67 points, and the R20 and R23 single-core gaps are 1.1 and 1.2 percent in the Opteron's favor.

Q: How much more power does the Opteron use?

A: The Opteron 6238 is rated at 115 W TDP versus 45 W for the Xeon D-1521, a substantial difference for servers running continuously.

Q: Which memory does each support?

A: The Opteron uses quad-channel DDR3 with 51.2 GB/s of bandwidth. The Xeon D-1521 supports both DDR3 and DDR4 on a dual-channel bus.

Q: Can either CPU still be purchased new?

A: The Xeon D-1521 is listed as active in the database. The Opteron 6238 is end-of-life.

Specification Differences

The two chips differ on nearly every line of the spec sheet. Cores: 12 for the Opteron versus 4 for the Xeon, with 12 threads versus 8. Base and boost clocks: 2.60/3.20 GHz against 2.40/2.70 GHz. TDP: 115 W against 45 W. Process node: 32 nm GlobalFoundries versus 14 nm Intel. Transistor count: 2,400 million versus 3,200 million, and die size: two dies of 315 mm² each versus a single 246 mm².

Sockets are incompatible: AMD Socket G34 versus soldered Intel BGA 1667. Cache layouts are entirely different: 768 KB of L1, 2 MB of L2 per module, and 8 MB of L3 per die on the AMD side, against 64 KB of L1, 256 KB of L2, and 1.5 MB of L3 per core on the Intel side. The Opteron's memory is DDR3-only on a quad-channel bus; the Xeon handles DDR3 and DDR4 on dual-channel. PCIe is Gen 2 on the Opteron versus Gen 3 with 24 CPU lanes on the Xeon. Release dates are November 13, 2011 versus October 31, 2015, production status is end-of-life versus active, and the launch MSRP figures were $455 for the Opteron 6238 and $199 for the Xeon D-1521. The Xeon's Broadwell architecture is the newer design of the two.

The Verdict

On raw benchmark results alone, neither chip meaningfully outperforms the other. The Opteron 6238's six-test sweep comes with margins of at most 1.2 percent, and both processors share the 36th percentile position. That makes the decision hinge entirely on the surrounding specifications.

The data favors the Opteron 6238 where platform bandwidth matters: quad-channel memory delivering 51.2 GB/s, more cores, and higher clocks. It is the pick for throughput-oriented workloads that can spread across 12 threads and saturate that wide memory bus.

The data favors the Xeon D-1521 everywhere else. It matches the Opteron's rendering performance with a 45 W TDP versus 115 W, offers newer DDR4 support, faster PCIe Gen 3 with 24 CPU lanes, a 14 nm process, and it is still an active product, while the Opteron is end-of-life. For any deployment where efficiency, I/O, or platform longevity matter, the recorded data clearly points to the Xeon.

Where Each One Wins

The Opteron 6238 wins on multi-core throughput, at least technically: it leads every multi-core test, including 4781 versus 4728 in Cinebench R23, and its quad-channel 51.2 GB/s memory bus suits bandwidth-hungry, heavily parallel workloads that need many physical cores.

The Xeon D-1521 wins on efficiency and platform modernity. It delivers statistically identical benchmark performance, including an exact 67-point tie in Cinebench R15 single-core, at roughly a third of the power budget implied by the TDP figures, with newer memory support and faster PCIe. Single-threaded and lightly threaded workloads are effectively equal between them, so the Xeon's efficiency makes it the safer default, while the Opteron's only remaining argument from the data is its core count and memory bandwidth in parallel rendering tasks.