Intel Xeon E3-1240 v5 vs Intel Xeon E3-1275 v5 Comparison

# Intel Xeon E3-1275 v5 vs Intel Xeon E3-1240 v5

The Intel Xeon E3-1275 v5 and Intel Xeon E3-1240 v5 are both 4-core, 8-thread Skylake-DT server/workstation processors on the Intel Socket 1151 platform, released on the same date with identical 80 W TDPs. The E3-1275 v5 carries a launch MSRP of $350, while the E3-1240 v5 launched at $282. Both sit at the 45th percentile among all CPUs in the database, with average benchmark scores of 2043 and 2030 respectively. The data shows a consistent, though modest, advantage for the E3-1275 v5 across every single benchmark test — six wins out of six head-to-head comparisons. This raises a compelling question: does the performance gap justify the price difference, or does the E3-1240 v5's nearly identical architecture make it the more rational choice for specific workloads?

Where Each One Wins

The E3-1275 v5 wins every benchmark in this comparison, but the margin is remarkably thin. In Cinebench R15 multi-core, it scores 712 against the E3-1240 v5's 707, a delta of just 0.7%. The single-core R15 test shows a 1% advantage (100 vs 99), which is the largest relative gap in the entire dataset. Moving to Cinebench R20, the E3-1275 v5 leads 2967 to 2948 (0.6% delta) in multi-core and 418 to 416 (0.5% delta) in single-core. The R23 results follow the same pattern: 7065 vs 7020 multi-core (0.6% delta) and 997 vs 991 single-core (0.6% delta).

These margins are so consistent that they suggest a clock-speed-driven advantage rather than any architectural superiority. The E3-1275 v5 has a 3.60 GHz base clock and 4.00 GHz boost clock, while the E3-1240 v5 runs at 3.50 GHz base and 3.90 GHz boost — exactly 100 MHz apart at both ends. Every benchmark delta falls between 0.5% and 1%, which aligns with a ~2.8% clock difference being partially diluted by other system factors. The E3-1240 v5's closest rival is the Intel Core i7-5775R (avg score 2031, delta -0.1%), while the E3-1275 v5's nearest competitor is the AMD Ryzen 5 7520U (avg score 2046, delta -0.1%). This places both Xeons in a tight performance cluster where no single processor dominates its peers by more than 0.3%.

For workloads that are heavily single-threaded — such as older software, lightly threaded database queries, or certain simulation tasks — the E3-1275 v5's higher boost clock gives it a slight edge. For purely multi-threaded workloads, the difference is nearly imperceptible in real-world terms. The E3-1240 v5, however, has one clear advantage that does not appear in benchmark scores: it lacks integrated graphics, which means it cannot drive a display without a discrete GPU. The E3-1275 v5 includes HD Graphics P530, making it a self-contained option for systems that need video output without an add-in card.

The Verdict

The data presents a straightforward picture: the E3-1275 v5 is faster in every measured test, but only by fractions of a percentage point. Its largest lead is 1% in Cinebench R15 single-core, and its smallest is 0.5% in R20 single-core. For users building a system where integrated graphics are required — perhaps for a compact workstation or a server with limited PCIe slots — the E3-1275 v5 is the only choice between these two, as the E3-1240 v5 offers no iGPU at all. The E3-1275 v5's launch MSRP of $350 reflects that additional functionality and its slightly higher clock speeds.

For users who already have a discrete GPU or who are running headless server workloads, the E3-1240 v5 at its $282 launch MSRP delivers essentially the same compute performance. The 0.6% to 0.7% multi-core deltas translate to negligible real-world differences in rendering, compilation, or data processing tasks. The E3-1240 v5's average benchmark score of 2030 places it within 0.1% of the Intel Core i7-5775R and within 0.2% of the Intel Xeon E3-1280 v5 and E3-1260L v5. Meanwhile, the E3-1275 v5's 2043 average score is within 0.2% of the Intel Xeon E3-1270 v5 and within 0.3% of the AMD Opteron 6386 SE.

The verdict hinges on the integrated graphics question. If the system requires onboard video output, the E3-1275 v5 wins by default — no amount of benchmark analysis changes that. If the system has a GPU, the E3-1240 v5 offers nearly identical performance at a lower launch price. The benchmark data does not show any scenario where the E3-1275 v5's performance advantage would be perceptible in daily use.

Head-to-Head Benchmarks

The most decisive result is the Cinebench R15 single-core test, where the E3-1275 v5 scores 100 against the E3-1240 v5's 99, a 1% delta. This is the only test where the gap reaches a full percentage point, and it reflects the 100 MHz boost clock advantage. The R15 multi-core test shows 712 vs 707 (0.7% delta), which is the second-largest margin. Both scores are remarkably close, suggesting that the memory bandwidth (34.1 GB/s for both) and shared L3 cache (8 MB for both) are not bottlenecks at this performance level.

In Cinebench R20, the multi-core results are 2967 vs 2948 (0.6% delta), and single-core results are 418 vs 416 (0.5% delta). The R23 tests continue the trend: multi-core 7065 vs 7020 (0.6% delta) and single-core 997 vs 991 (0.6% delta). Every single test — all six of them — goes to the E3-1275 v5. The consistency is notable: there is no test where the E3-1240 v5 pulls ahead or even ties.

What is equally interesting is how both processors compare to their nearest rivals. The E3-1275 v5's average score of 2043 is only 0.1% below the AMD Ryzen 5 7520U's 2046 and 0.2% above the Intel Core i7-7700T's 2039. The E3-1240 v5's 2030 average is 0.1% below the Intel Core i7-5775R's 2031 and 0.1% above the Intel Xeon E3-1280 v5's 2029. Neither Xeon dominates its competitive set; they sit in a dense cluster of similarly performing parts.

FAQ

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

A: The Intel Xeon E3-1275 v5 wins all three single-core tests (R15, R20, R23) with scores of 100, 418, and 997 respectively, against the E3-1240 v5's 99, 416, and 991. The largest margin is 1% in R15.

Q: What is the performance difference in multi-core tests?

A: The E3-1275 v5 leads in all three multi-core tests: R15 (712 vs 707, 0.7% delta), R20 (2967 vs 2948, 0.6% delta), and R23 (7065 vs 7020, 0.6% delta).

Q: Do these processors have integrated graphics?

A: No — the Intel Xeon E3-1275 v5 includes HD Graphics P530, while the Intel Xeon E3-1240 v5 has no integrated graphics at all.

Q: How do these chips compare to their closest rivals?

A: The E3-1275 v5 averages 2043, sitting 0.1% below the AMD Ryzen 5 7520U and 0.2% above the Intel Core i7-7700T. The E3-1240 v5 averages 2030, placing it 0.1% below the Intel Core i7-5775R and 0.1% above the Intel Xeon E3-1280 v5.

Q: Which processor has the higher clock speeds?

A: The E3-1275 v5 runs at 3.60 GHz base and 4.00 GHz boost, while the E3-1240 v5 runs at 3.50 GHz base and 3.90 GHz boost.

Q: Do both processors support ECC memory?

A: Yes, both the E3-1275 v5 and E3-1240 v5 support ECC memory with dual-channel DDR3 and DDR4, both rated at 34.1 GB/s memory bandwidth.

Architecture Differences

Both processors share the same fundamental architecture: Skylake-DT on a 14 nm process node, fabricated by Intel with 1,750 million transistors on a 122 mm² die. Both have 4 cores and 8 threads with identical cache hierarchies — 64 KB L1 per core, 256 KB L2 per core, and 8 MB shared L3. The memory controllers are identical as well, supporting both DDR3 and DDR4 in dual-channel configuration with 34.1 GB/s bandwidth, plus ECC support. Both use the Intel Socket 1151 and PCIe Gen 3 with 16 lanes (CPU only).

The architectural difference is limited to two areas. First, the integrated graphics: the E3-1275 v5 includes HD Graphics P530, while the E3-1240 v5 has no iGPU. This is a silicon-level difference that affects the die's functionality but not its compute performance in CPU-bound tasks. Second, the clock speeds differ by 100 MHz at both base and boost — the E3-1275 v5 at 3.60/4.00 GHz versus the E3-1240 v5 at 3.50/3.90 GHz. This clock gap is the sole driver of the benchmark differences observed. Both processors are unlocked? No — neither has an unlocked multiplier, so overclocking is not an option for closing the gap.

The production status for both is end-of-life, and both were released on October 18, 2015. The part numbers differ: SR2LKSR2CT for the E3-1275 v5 and SR2LD for the E3-1240 v5. Both target the server/workstation market segment.

Specification Differences

The only specification differences between these two processors are clock speeds, integrated graphics, launch MSRP, and part number. The E3-1275 v5 has a base clock of 3.60 GHz and a boost clock of 4.00 GHz, while the E3-1240 v5 operates at 3.50 GHz base and 3.90 GHz boost. The E3-1275 v5 includes HD Graphics P530; the E3-1240 v5 has no integrated graphics. The launch MSRP is $350 for the E3-1275 v5 and $282 for the E3-1240 v5. Part numbers are SR2LKSR2CT and SR2LD respectively.

All other specifications are identical: 4 cores, 8 threads, 80 W TDP, Intel Socket 1151, Skylake architecture, 14 nm process, 1,750 million transistors, 122 mm² die size, 64 KB L1 per core, 256 KB L2 per core, 8 MB shared L3, DDR3/DDR4 dual-channel memory with 34.1 GB/s bandwidth, ECC support, PCIe Gen 3 with 16 lanes, server/workstation market segment, end-of-life production status, October 18, 2015 release date, and locked multipliers. Both processors sit at the 45th percentile in the database. The benchmark deltas — all between 0.5% and 1% — are entirely attributable to the 100 MHz clock advantage of the E3-1275 v5, making the integrated graphics the true differentiator between these two otherwise equivalent parts.