CPU Comparison

The Intel Xeon E3-1235L v5 and the Intel Xeon E5645 represent two very different eras of server silicon, yet their benchmark scores place them in a surprisingly tight contest. The E3-1235L v5, a 14nm Skylake part from 2015, edges out the older 32nm Westmere E5645 from 2010 across every single Cinebench test in the data. However, the margins are razor-thin, with the newer chip winning by less than 2% in all six head-to-head comparisons. The data shows a generational clash where architectural efficiency and raw core count nearly cancel each other out, leaving the decision to finer details like platform features and power characteristics.

Head-to-Head Benchmarks

The benchmark results paint a picture of consistent, albeit narrow, dominance for the Intel Xeon E3-1235L v5. In the multi-threaded Cinebench R15 test, the E3-1235L v5 scores 429 against the E5645’s 421, a delta of 1.9%. This pattern repeats in Cinebench R20 multicore, where the E3-1235L v5 posts 1789 versus 1758, a 1.8% advantage. The R23 multicore run shows a similar story: 4261 for the E3-1235L v5 against 4187 for the E5645, again a 1.8% lead. These are not the blowout victories one might expect from a five-year newer architecture; the E5645’s 6 cores and 12 threads clearly keep it competitive in heavily threaded workloads.

Single-core performance tells a comparable tale, with the E3-1235L v5 taking slim wins across the board. In Cinebench R15 single-core, the score is 60 versus 59, a 1.7% margin. The R20 single-core test yields 252 against 248, a 1.6% advantage. The R23 single-core result is 601 versus 591, another 1.7% edge for the Skylake part. While the E3-1235L v5 wins all six head-to-head matchups, the largest delta is just 1.9%, indicating that per-core throughput is remarkably similar between these two processors despite their different designs.

Looking at the broader context, both chips sit at the 34th percentile among all CPUs, meaning they occupy the same performance tier in the grand scheme of the benchmark database. The E3-1235L v5 has an average benchmark score of 1232, while the E5645 trails slightly at 1211. The nearest rivals for the E3-1235L v5 include the Intel Core i3-8109U at 1235 (-0.2% delta) and the Intel Core i5-2500 at 1220 (1% delta), while the E5645’s closest competitor is the Intel Core i3-7300T at 1211 (0% delta). These comparisons reinforce that both Xeons deliver performance roughly equivalent to a modern low-end Core i3, not the high-end workstation muscle their server branding might suggest.

Architecture Differences

The architectural gulf between these two Xeons is vast, yet it manifests in nearly identical benchmark outcomes. The E3-1235L v5 is built on Intel’s 14nm process node, packing 1,750 million transistors into a 122 mm² die. Its Skylake-DT architecture features 4 cores and 4 threads, with base and boost clocks of 2000 MHz and 3000 MHz respectively. The E5645, by contrast, uses the older 32nm process, integrating 1,170 million transistors across a much larger 239 mm² die. Its Westmere-EP design offers 6 cores and 12 threads, but with a lower boost ceiling: 2400 MHz base and 2670 MHz boost.

Cache configurations also differ significantly. The E3-1235L v5 has 64 KB of L1 and 256 KB of L2 per core, with 8 MB of shared L3. The E5645 provides the same per-core L1 and L2 allocations, but doubles the shared L3 to 12 MB. This extra cache likely helps the older chip compensate for its slower clock speeds and less efficient architecture. Memory support is another differentiator: the E3-1235L v5 supports both DDR3 and DDR4 in a dual-channel configuration with 34.1 GB/s of bandwidth, while the E5645 is limited to DDR3 over a triple-channel bus with no bandwidth figure listed in the data.

Platform features diverge sharply. The E3-1235L v5 uses the Intel Socket 1151, integrates HD Graphics P530, and offers PCIe Gen 3 with 16 CPU lanes. The E5645 uses the older Intel Socket 1366, has no integrated graphics, and only supports PCIe Gen 2. Both support ECC memory, but the E3-1235L v5’s 25W TDP is a dramatic departure from the E5645’s 80W TDP. The E3-1235L v5 also carries a launch MSRP of $250, while no launch price is recorded for the E5645. Both chips are end-of-life, with the E3-1235L v5 released in October 2015 and the E5645 in March 2010.

The Verdict

The benchmark data makes no case for a decisive winner on raw performance alone. The Intel Xeon E3-1235L v5 takes all six head-to-head wins, but by margins of 1.6% to 1.9%, which in real-world use would be imperceptible. The E5645’s advantage of two additional cores and eight additional threads is entirely neutralized by the E3-1235L v5’s superior per-core efficiency and higher boost clock. The data shows that in Cinebench workloads, the newer 4-core part and the older 6-core part are effectively performance peers.

The clear differentiators are not benchmark scores but platform characteristics. The E3-1235L v5 offers a 25W TDP, integrated graphics, DDR4 support, and PCIe Gen 3, making it the obvious choice for a low-power, modern server or workstation build. The E5645’s 80W TDP and lack of integrated graphics render it less attractive for energy-conscious deployments, despite its extra cores and larger L3 cache. From the data, the E3-1235L v5 is the better purchase for almost any scenario, as it matches the E5645’s performance while drawing a fraction of the power and supporting newer memory and I/O standards. The E5645 only makes sense if you have a legacy Socket 1366 platform and need to maximize core count within that constraint.

FAQ

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

A: The Intel Xeon E3-1235L v5 scores 4261 in Cinebench R23 multicore, while the Intel Xeon E5645 scores 4187, giving the E3-1235L v5 a 1.8% lead.

Q: How do the core counts and thread counts compare?

A: The Intel Xeon E5645 has 6 cores and 12 threads, while the Intel Xeon E3-1235L v5 has 4 cores and 4 threads.

Q: Does the newer E3-1235L v5 support DDR4 memory?

A: Yes, the E3-1235L v5 supports both DDR3 and DDR4 memory in a dual-channel configuration, while the E5645 only supports DDR3 over a triple-channel bus.

Q: What are the thermal design power (TDP) ratings for each chip?

A: The Intel Xeon E3-1235L v5 has a TDP of 25W, whereas the Intel Xeon E5645 has a TDP of 80W.

Q: Which processor includes integrated graphics?

A: Only the Intel Xeon E3-1235L v5 includes integrated graphics, specifically HD Graphics P530. The Intel Xeon E5645 has no integrated graphics.

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

A: The Intel Xeon E3-1235L v5 has an average benchmark score of 1232, while the Intel Xeon E5645 has an average benchmark score of 1211.

Where Each One Wins

The Intel Xeon E3-1235L v5 wins on every benchmark metric recorded in the data, but its true advantages lie outside Cinebench scores. Its 25W TDP makes it suitable for compact, low-power server builds where thermal management is a priority. The integration of HD Graphics P530 eliminates the need for a discrete GPU in basic display scenarios. Support for DDR4 memory and PCIe Gen 3 brings modern memory bandwidth and I/O capabilities. The 14nm process node and smaller 122 mm² die also suggest greater manufacturing efficiency, though the data does not directly measure this.

The Intel Xeon E5645 wins only in terms of raw core count, 6 cores versus 4, and thread count, 12 threads versus 4. It also offers a larger 12 MB shared L3 cache compared to the E3-1235L v5’s 8 MB. For workloads that scale with cache size or benefit from more physical cores, the E5645 could theoretically hold an advantage, but the Cinebench results in the data show no such benefit materializing. The triple-channel DDR3 memory bus is a unique feature, though no bandwidth figure is provided to quantify its impact. In the context of the benchmark database, the E5645’s wins are structural rather than observed, making it a niche choice for legacy platform upgrades.