CPU Comparison

Both the Intel Xeon E5-4640 v3 and the Intel Xeon E5-1650 v3 are Haswell-EP server processors sharing the same 22 nm process node, 2,600 million transistors, and 356 mm² die size, yet they are engineered for completely different deployment scenarios. The E5-4640 v3 emphasizes core-count scalability for multi-threaded server workloads, while the E5-1650 v3 prioritizes raw clock speed for latency-sensitive tasks. Benchmark data reveals a remarkably tight contest between the two, with the 12-core part winning every head-to-head test by a margin of 0.2% or less, despite the 6-core part’s substantial clock advantage. This outcome challenges conventional assumptions about core-count versus frequency trade-offs and suggests that architectural efficiency and cache configuration play a decisive role in real-world performance parity.

FAQ

Q: Which processor has more cores and threads?

A: The Intel Xeon E5-4640 v3 has 12 cores and 24 threads, while the Intel Xeon E5-1650 v3 has 6 cores and 12 threads. This is a 2x difference in parallel processing capacity.

Q: How do their base and boost clocks compare?

A: The E5-1650 v3 runs at a 3.50 GHz base clock and boosts to 3.80 GHz. The E5-4640 v3 is significantly slower in raw frequency, with a 1.90 GHz base clock and a 2.60 GHz boost clock.

Q: Which CPU has more L3 cache?

A: The E5-4640 v3 offers 30 MB of shared L3 cache, exactly double the 15 MB found on the E5-1650 v3. This larger cache likely compensates for its lower clock speeds in multi-threaded tests.

Q: What is the average benchmark score difference between the two?

A: The E5-4640 v3 has an average benchmark score of 2550, while the E5-1650 v3 scores 2545. This represents a 0.2% advantage for the 12-core model, making them effectively performance equals in aggregate.

Q: Are both CPUs compatible with the same memory configuration?

A: Yes, both use DDR4 memory with quad-channel support and 40 PCIe Gen 3 lanes. However, the E5-1650 v3 has higher memory bandwidth at 68.3 GB/s versus 59.7 GB/s for the E5-4640 v3.

Q: Which CPU has an unlocked multiplier?

A: The Intel Xeon E5-1650 v3 has an unlocked multiplier, whereas the E5-4640 v3 is locked. This means the 6-core part offers overclocking flexibility that the 12-core part lacks.

Architecture Differences

Both processors are built on the same Haswell-EP architecture, codenamed Haswell-EP, and fabricated on Intel’s 22 nm process. They share identical transistor counts (2,600 million) and die size (356 mm²), indicating they are derived from the same silicon design. The fundamental architectural divergence lies in how the silicon is configured: the E5-4640 v3 activates 12 cores with 24 threads, while the E5-1650 v3 activates only 6 cores with 12 threads.

The cache hierarchy reflects this core-count difference. Each core on both chips has 64 KB of L1 cache and 256 KB of L2 cache, but the shared L3 cache scales with the active core count. The E5-4640 v3 has 30 MB of shared L3, while the E5-1650 v3 has 15 MB. This 2x difference in L3 cache is proportional to the core difference, suggesting that each core has a consistent cache allocation. The clock speeds, however, diverge dramatically. The E5-1650 v3 runs at a 3.50 GHz base and 3.80 GHz boost, while the E5-4640 v3 limps along at 1.90 GHz base and 2.60 GHz boost. This 1.6 GHz base clock gap is the largest architectural distinction, and it has profound implications for single-threaded performance.

Memory bandwidth also differs, with the E5-1650 v3 achieving 68.3 GB/s versus 59.7 GB/s for the E5-4640 v3. Since both support quad-channel DDR4, this likely stems from the higher clock speed enabling faster memory access. The E5-1650 v3 also has an unlocked multiplier, making it the only one of the two that can be overclocked. Both chips support ECC memory and are classified as server/workstation parts, but they share the same socket (Intel Socket 2011-3) and PCIe configuration (Gen 3, 40 lanes).

Where Each One Wins

Based on the benchmark results, the E5-4640 v3 wins every single test, but the margins are razor-thin. In multi-core tests, the 12-core part’s advantage ranges from 0.1% to 0.2% over its 6-core sibling. For example, in Cinebench R23 multi-core, the E5-4640 v3 scores 8816 versus 8800 for the E5-1650 v3, a 0.2% lead. This is surprising given the 6-core part’s much higher clock speed, but the extra six cores and double L3 cache clearly compensate.

In single-core tests, the E5-4640 v3 also edges ahead, but the differences are negligible. Cinebench R23 single-core shows 1244 for the 12-core part versus 1242 for the 6-core part, a 0.2% margin. This suggests that despite the 1.3 GHz boost clock deficit, the E5-4640 v3’s architecture delivers nearly identical single-thread performance. The data implies that neither chip has a clear use-case advantage in raw compute; the E5-4640 v3 is marginally better everywhere.

The practical implication is that the E5-4640 v3 is the safer choice for multi-threaded server workloads like virtualization, database processing, or render farms, where its additional cores provide headroom. The E5-1650 v3, with its unlocked multiplier, could be positioned for workstation users who want to overclock for single-threaded tasks, but the benchmark data does not show it winning any test even at stock settings. The E5-4640 v3’s wins, however, are so small that they fall within noise margins, making the choice more about platform features than performance.

Specification Differences

The two processors differ in several key specifications, with the most notable being core count, clock speed, TDP, and cache. The E5-4640 v3 has 12 cores and 24 threads, while the E5-1650 v3 has 6 cores and 12 threads. Base clock speeds are 1.90 GHz versus 3.50 GHz, and boost clocks are 2.60 GHz versus 3.80 GHz, favoring the 6-core part.

L3 cache differs by 2x: 30 MB on the E5-4640 v3 versus 15 MB on the E5-1650 v3. Memory bandwidth also varies, with the E5-1650 v3 at 68.3 GB/s versus 59.7 GB/s for the E5-4640 v3. TDP is another differentiator, with the E5-4640 v3 drawing 105 watts compared to 140 watts for the E5-1650 v3, meaning the 12-core part is more power-efficient per core.

The multiplier unlock status differs, with only the E5-1650 v3 having an unlocked multiplier. The E5-4640 v3 has a launch MSRP of $2859, while the E5-1650 v3 has no listed launch MSRP. The E5-4640 v3 was released on 2015-05-31, while the E5-1650 v3 came earlier on 2014-09-07. Part numbers also differ (SR22L versus QFSTSR20J), but the socket, architecture, process node, transistors, die size, memory support, PCIe configuration, and ECC support are identical.

Head-to-Head Benchmarks

The head-to-head benchmark data shows a consistent, if narrow, victory for the E5-4640 v3 across all six Cinebench tests. The largest margin of victory is 0.2%, achieved in four tests: Cinebench R20 multi-core (3702 vs 3696), Cinebench R20 single-core (522 vs 521), Cinebench R23 multi-core (8816 vs 8800), and Cinebench R23 single-core (1244 vs 1242). The smallest margin is 0% in Cinebench R15 single-core, where both chips score exactly 125.

In Cinebench R15 multi-core, the E5-4640 v3 scores 888 versus 887, a 0.1% lead. This pattern is remarkable because the E5-1650 v3 has a 1.6 GHz base clock advantage and a 1.2 GHz boost clock advantage, yet it cannot overcome the E5-4640 v3’s core count and cache size. The data suggests that the 12-core part’s 2x thread count and 2x L3 cache are sufficient to neutralize the frequency deficit entirely.

The single-core results are even more telling. Despite a 1.3 GHz boost clock disadvantage, the E5-4640 v3 matches or slightly exceeds the E5-1650 v3 in every single-core test. This implies that Haswell-EP’s core architecture is not clock-limited in these workloads, or that the larger L3 cache provides a hit-rate advantage that compensates for lower frequency. The average benchmark scores confirm this parity: 2550 for the E5-4640 v3 versus 2545 for the E5-1650 v3, a 0.2% aggregate difference.

The Verdict

The data presents an unusual conclusion: the E5-4640 v3 is the superior processor in every measured benchmark, despite having dramatically lower clock speeds and a higher core count. The 12-core part wins all six tests with margins of 0.1% to 0.2%, and its average benchmark score of 2550 edges out the E5-1650 v3’s 2545 by 0.2%. This makes the E5-4640 v3 the statistically better choice for any workload, whether single-threaded or multi-threaded.

However, the practical differences are negligible. A 0.2% performance delta is within typical run-to-run variance, meaning most users would not notice a difference in real-world applications. The E5-4640 v3’s lower TDP (105 watts versus 140 watts) gives it an efficiency advantage, and its 30 MB L3 cache provides more headroom for cache-sensitive workloads. The E5-1650 v3’s unlocked multiplier offers overclocking potential, but the benchmark data does not indicate that stock performance benefits from this feature.

For server deployments where multi-threaded throughput and power efficiency matter, the E5-4640 v3 is the clear pick. For workstation users considering overclocking, the E5-1650 v3’s unlocked multiplier is its only real selling point, as its stock performance is marginally worse. Given the E5-4640 v3’s 0.2% average score advantage and its 12-core/24-thread configuration, the data favors the 12-core part for virtually every scenario. The E5-1650 v3’s higher memory bandwidth (68.3 GB/s vs 59.7 GB/s) is its sole specification win, but this does not translate into benchmark victories.