Intel Core i7-3820 vs Intel Xeon E3-1515M v5 Comparison

The Intel Xeon E3-1515M v5 and the Intel Core i7-3820 are two end-of-life quad-core processors that land within a hair of each other in overall benchmark performance, yet they represent entirely different design philosophies. The Xeon, a mobile workstation part on 14 nm Skylake-H silicon, sweeps every Cinebench test in the database despite drawing far less power. The i7-3820, a desktop Sandy Bridge-E chip, counters with more L3 cache, quad-channel memory, and a vastly larger PCIe lane budget. The recorded data makes the call clear: the Xeon is the faster, more efficient CPU on every test, but the i7-3820 holds platform advantages the benchmarks do not capture.

FAQ

Q: Which CPU is faster in benchmarks?

A: The Xeon E3-1515M v5 wins all six recorded Cinebench tests. Its average benchmark score of 1456 edges out the i7-3820's 1424, and its single-core leads range from 2.3% to 2.9% depending on the test version.

Q: How close are these two CPUs overall?

A: Very close. Both sit near the same tier of the database: the Xeon lands in the 38th percentile versus all CPUs, the i7-3820 in the 37th. The Xeon's average score sits within 0.3% of the AMD Ryzen 3 PRO 2200GE and 0.4% of the Intel Core i3-7350K, while the i7-3820 is nearly tied with the Intel Xeon Bronze 3106 and Intel Core i5-4570S.

Q: Which chip has the lower power draw?

A: The Xeon E3-1515M v5, with a TDP of 45W versus 130W for the i7-3820. That is the most one-sided specification difference between the two, and it comes alongside better performance in every test.

Q: Can either CPU be overclocked?

A: Only the i7-3820. Its multiplier is unlocked, while the Xeon's is locked. The Xeon boosts to 3.70 GHz from a 2.80 GHz base; the i7-3820 runs a 3.60 GHz base with a 3.80 GHz boost.

Q: Which platform has more connectivity?

A: The i7-3820, by a wide margin. It offers 40 PCIe Gen 2 lanes versus the Xeon's 16 PCIe Gen 3 lanes, plus a quad-channel DDR3 memory bus delivering 51.2 GB/s of bandwidth against the Xeon's dual-channel 34.1 GB/s.

Q: Which CPU has integrated graphics?

A: Only the Xeon E3-1515M v5, which integrates Iris Pro Graphics P580. The i7-3820 has no integrated graphics and requires a discrete GPU.

The Verdict

The data delivers a clean verdict on raw performance: the Xeon E3-1515M v5 is the better processor, full stop. It wins all six head-to-head Cinebench tests, posts a higher average benchmark score (1456 versus 1424), and does so at roughly a third of the power draw (45W versus 130W TDP). It also sits one percentile point higher against the full CPU database.

The i7-3820 still has a defensible case, but only on platform grounds rather than CPU performance. Its unlocked multiplier offers tuning headroom the locked Xeon cannot match, its 10 MB of shared L3 cache exceeds the Xeon's 8 MB, its quad-channel memory bus provides substantially more bandwidth, and its 40 PCIe lanes dwarf the Xeon's 16. For workloads that hinge on memory bandwidth, lane count, or overclocking rather than core throughput, the i7-3820 remains the more capable platform despite losing every benchmark.

For ECC memory support, the choice is again the Xeon, which is unsurprising given its Server/Workstation market segment.

Head-to-Head Benchmarks

The Xeon's sweep is consistent rather than dramatic, but it is total: six tests, six wins, margins between 2.2% and 2.9%.

In Cinebench R15, the Xeon scores 507 multi-core points to the i7-3820's 496, a 2.2% lead, and 71 single-core points to 69, a 2.9% lead. Cinebench R20 tells the same story: 2115 versus 2067 in multi-core (2.3%) and 298 versus 291 in single-core (2.4%). The newest test in the database, Cinebench R23, lands at 5036 versus 4923 in multi-core (2.3%) and 711 versus 695 in single-core (2.3%).

Two patterns stand out. First, the margins are remarkably stable across test generations, indicating the Skylake architecture's advantage is architectural rather than an artifact of any single benchmark. Second, the Xeon achieves these leads while boosting lower (3.70 GHz versus 3.80 GHz) and drawing 45W versus 130W. The newer 14 nm node is doing the heavy lifting: more performance per clock, and dramatically more performance per watt.

Context from the database reinforces how tightly matched these chips are overall. The Xeon's average score of 1456 sits 0.3% above the Ryzen 3 PRO 2200GE (1461 average, -0.3% delta) and 0.4% above the Core i3-7350K (1462, -0.4%), while holding a 0.6% edge over the Core i5-7300HQ (1448) and the Opteron 6378 (1447). The i7-3820's 1424 average is essentially identical to the Xeon Bronze 3106 (1422), Core i5-4570S (1426), Core i7-3720QM (1421), and Opteron 4274 HE (1420). These are the same performance neighborhood, with the Xeon consistently on the higher floor.

Specification Differences

The two chips share a 4-core, 8-thread layout and identical per-core L1 (64 KB) and L2 (256 KB) cache, but diverge almost everywhere else:

• Base/boost clocks: Xeon at 2.80/3.70 GHz; i7-3820 at 3.60/3.80 GHz. The i7-3820 runs the higher base, the Xeon closes the gap at boost.
• TDP: 45W for the Xeon versus 130W for the i7-3820.
• Socket: Intel BGA 1440 (soldered) for the Xeon versus Intel Socket 2011 for the i7-3820.
• L3 cache: 8 MB shared on the Xeon versus 10 MB shared on the i7-3820.
• Memory: The Xeon supports DDR3 and DDR4 on a dual-channel bus at 34.1 GB/s with ECC; the i7-3820 supports DDR3 only on a quad-channel bus at 51.2 GB/s without ECC.
• PCIe: Gen 3, 16 lanes on the Xeon versus Gen 2, 40 lanes on the i7-3820.
• Graphics: Iris Pro Graphics P580 integrated on the Xeon; none on the i7-3820.
• Multiplier: locked on the Xeon, unlocked on the i7-3820.
• Launch MSRP: $489 for the Xeon, $305 for the i7-3820.
• Release: the i7-3820 shipped 2012-02-12; the Xeon followed on 2016-01-23.

Architecture Differences

Four years and two process generations separate these designs. The i7-3820 is Sandy Bridge-E, built on Intel's 32 nm process with 1,270 million transistors on a 294 mm² die. The Xeon E3-1515M v5 is Skylake-H on 14 nm, packing 2,300 million transistors into a smaller 171 mm² die. Nearly double the transistor count on a much smaller die, at a fraction of the power budget, is the clearest illustration of the architectural gulf.

The Skylake-H design also brings newer platform features: DDR4 memory support alongside DDR3, PCIe Gen 3 connectivity, and ECC capability, all consistent with its Server/Workstation segmentation. Sandy Bridge-E takes a different approach entirely: a larger die with more L3 cache and a quad-channel memory controller, designed for a high-power desktop socket with massive lane counts. The Xeon integrates Iris Pro Graphics P580 on-die; the i7-3820's die makes no provision for graphics at all.

The benchmark payoff of Skylake's newer microarchitecture is visible despite the clock disadvantage: the Xeon wins every test while boosting 0.10 GHz lower than the i7-3820.

Where Each One Wins

Xeon E3-1515M v5 wins on:

• Raw benchmark performance: all six Cinebench tests, by 2.2% to 2.9%
• Efficiency: higher scores at 45W versus 130W
• Single-thread responsiveness: 711 versus 695 in Cinebench R23 single-core
• Modern memory support: DDR4 alongside DDR3
• Data integrity: ECC memory support
• Integrated graphics: Iris Pro Graphics P580 with no discrete GPU required
• Newer platform connectivity: PCIe Gen 3 lanes, albeit only 16 of them

Core i7-3820 wins on:

• Platform bandwidth: quad-channel memory at 51.2 GB/s versus 34.1 GB/s
• Expansion: 40 PCIe lanes versus 16, for multi-GPU or add-in card heavy builds
• Cache capacity: 10 MB shared L3 versus 8 MB
• Overclocking: unlocked multiplier versus locked
• Socket flexibility: a replaceable Socket 2011 part versus soldered BGA 1440

The final tally is 6-0 in benchmarks for the Xeon, and the database percentile agrees (38 versus 37). But the i7-3820's wins are real ones for a specific kind of builder: one who needs lanes, bandwidth, and tuning freedom more than a two-to-three percent edge in CPU throughput.