Intel Core i7-8665U vs Intel Xeon E3-1225 v5 Comparison

The Intel Core i7-8665U and the Intel Xeon E3-1225 v5 are both end-of-life processors from Intel, but they target very different segments: the i7-8665U is a mobile chip built for thin laptops, while the Xeon E3-1225 v5 is a server and workstation part. The database records six Cinebench comparisons between them, and the results are one-sided. The i7-8665U wins every single test, with margins ranging from 2.8% to 3.3%. This article breaks down those benchmark results, the architectural differences that explain them, and which processor is the better pick for specific workloads.

Head-to-Head Benchmarks

The head-to-head data covers three generations of Cinebench: R15, R20, and R23, each with a multi-core and a single-core run. In all six tests, the Intel Core i7-8665U comes out ahead. The smallest margin is in Cinebench R15 single-core, where the i7 scores 74 against the Xeon's 72, a 2.8% advantage. The largest margins are 3.3%, appearing in Cinebench R15 multi-core (527 vs 510), Cinebench R20 multi-core (2197 vs 2127), and Cinebench R23 multi-core (5232 vs 5065). The single-core results in R20 and R23 are nearly as decisive: 309 vs 300 (3% ahead) and 738 vs 715 (3.2% ahead) respectively.

These are not trivial differences. A 3.3% lead in multi-core rendering means the i7-8665U completes the same workload in measurably less time, and the consistency across all six tests suggests the advantage is structural, not a one-off run. The Xeon E3-1225 v5 never takes a single win. Its best showing is in R15 single-core, where it trails by only 2 points, but that still leaves it behind. The average benchmark score in the database tells the same story: the i7-8665U averages 1513 points, while the Xeon averages 1465. Both processors sit at the 38th percentile of all CPUs, meaning they are in the same performance tier overall, but the i7 is consistently at the top of that tier.

For context, the i7-8665U's nearest rivals in the database include the Intel Pentium Gold G7400E (average score 1524, 0.7% higher) and the Intel Core i5-4670S (1526, 0.9% higher). The Xeon E3-1225 v5's nearest rivals include the Intel Core i3-7350K (1462, 0.2% lower) and the AMD Ryzen 3 PRO 2200GE (1461, 0.3% lower). So while the i7-8665U is slightly below the Pentium Gold and Core i5-4670S in average score, it is clearly above the Xeon. The Xeon, in turn, is essentially tied with a Core i3 and a Ryzen 3, which underscores its mid-range position.

Architecture Differences

The two CPUs share a 14 nm process node and the same per-core cache layout: 64 KB of L1 and 256 KB of L2 per core, plus 8 MB of shared L3. Both support DDR3 and DDR4 memory in a dual-channel configuration, and both use PCIe Gen 3 with 16 lanes from the CPU. But the similarities end there.

The i7-8665U is a Whiskey Lake part, specifically Whiskey Lake-U, built for mobile systems. It has 4 cores and 8 threads, thanks to Hyper-Threading. Its base clock is 1900 MHz, but it boosts up to 4800 MHz, a very high single-core turbo for a 15 W TDP chip. The Xeon E3-1225 v5 is a Skylake-DT part, a desktop/server chip with 4 cores and 4 threads, no Hyper-Threading. Its base clock is 3300 MHz, which is much higher than the i7's base, but its boost clock is only 3700 MHz, over 1 GHz lower than the i7's maximum. The Xeon has an 80 W TDP, more than five times the i7's 15 W, reflecting its desktop power envelope.

Memory bandwidth also differs: the i7-8665U records 38.4 GB/s, while the Xeon E3-1225 v5 records 34.1 GB/s. The i7 has a slight edge here, despite being a mobile part. The Xeon, however, supports ECC memory, while the i7 does not. That is a critical feature for server and workstation reliability. The integrated graphics differ as well: the i7 uses UHD Graphics 620, the Xeon uses HD Graphics P530. Neither is a gaming powerhouse, but they are present for basic display output.

The sockets are incompatible: the i7-8665U uses Intel BGA 1528, a soldered mobile socket, while the Xeon uses Intel Socket 1151, a standard desktop LGA socket. The Xeon also has a larger die (122 mm²) and a transistor count of 1,750 million, while the i7's die size and transistor count are not recorded in the database. The release dates are far apart: the i7-8665U launched in September 2018, the Xeon in October 2015. The launch MSRP for the i7-8665U is $409, and for the Xeon E3-1225 v5 it is $224. Both are end-of-life.

The Verdict

The benchmark data is unambiguous: the Intel Core i7-8665U outperforms the Intel Xeon E3-1225 v5 in every recorded Cinebench test. The i7's higher boost clock (4800 MHz vs 3700 MHz) and its extra threads (8 vs 4) give it a clear advantage in both single-core and multi-core workloads. The Xeon's higher base clock (3300 MHz vs 1900 MHz) does not translate into a win, because the i7's turbo can sustain higher frequencies under load, and the Xeon's lack of Hyper-Threading hurts in multi-threaded rendering.

So who should pick which? If you need raw performance in Cinebench-style workloads, the i7-8665U is the better choice. It wins all six tests, has a higher average benchmark score (1513 vs 1465), and offers a higher memory bandwidth. The Xeon E3-1225 v5, on the other hand, is the only one of the two that supports ECC memory. That makes it the appropriate pick for a server or workstation where data integrity is paramount, even if it means accepting lower benchmark scores. The Xeon also has a much higher base clock, which could be beneficial in workloads that do not boost well, but the recorded data does not show any such advantage.

The i7-8665U is a mobile processor, so it is not a direct replacement for a socketed Xeon in a desktop system. But if you are comparing them purely on performance, the i7 wins. The Xeon's only clear wins are in ECC support and its lower launch MSRP, but the latter is not a performance metric. The verdict from the data: the i7-8665U is the faster CPU, while the Xeon E3-1225 v5 is the more reliable choice for ECC-dependent environments.

FAQ

Q: Which CPU has the higher multi-core performance?

A: The Intel Core i7-8665U wins all three multi-core Cinebench tests. In R15, it scores 527 vs 510 (3.3% ahead); in R20, 2197 vs 2127 (3.3% ahead); in R23, 5232 vs 5065 (3.3% ahead).

Q: Does the Xeon E3-1225 v5 support ECC memory?

A: Yes, the Xeon E3-1225 v5 supports ECC memory, while the Intel Core i7-8665U does not. This is a key differentiator for server and workstation use.

Q: What are the core and thread counts?

A: The i7-8665U has 4 cores and 8 threads. The Xeon E3-1225 v5 has 4 cores and 4 threads.

Q: Which CPU has a higher boost clock?

A: The i7-8665U boosts up to 4800 MHz, while the Xeon E3-1225 v5 boosts up to 3700 MHz. The Xeon has a higher base clock (3300 MHz vs 1900 MHz), but the i7's turbo is much higher.

Q: Are these CPUs on the same process node?

A: Yes, both are built on Intel's 14 nm process node. They also share the same per-core cache sizes and 8 MB of shared L3.

Q: What is the average benchmark score for each?

A: The i7-8665U has an average benchmark score of 1513, while the Xeon E3-1225 v5 has an average of 1465. Both sit at the 38th percentile of all CPUs.

Where Each One Wins

The Intel Core i7-8665U wins in every performance category recorded in the database. It is ahead in all six Cinebench tests, covering both single-core and multi-core workloads. Its higher boost clock and additional threads make it the better choice for rendering, video encoding, and any application that scales with thread count. The i7 also has a higher memory bandwidth (38.4 GB/s vs 34.1 GB/s), which can help in memory-intensive tasks. For mobile users, the i7's 15 W TDP is a major advantage, as it allows for thinner, cooler laptops without sacrificing performance.

The Intel Xeon E3-1225 v5 wins in one specific area: ECC memory support. That is not a benchmark metric, but it is a critical feature for servers, workstations, and any system where a single-bit memory error could corrupt data. The Xeon also has a higher base clock (3300 MHz vs 1900 MHz), which could be useful in workloads that do not benefit from turbo boosting, but the recorded Cinebench results do not show any such advantage. The Xeon's lower launch MSRP ($224 vs $409) is a cost consideration, but the database does not include price-performance metrics.

In summary, the i7-8665U is the clear winner in raw performance, taking all six head-to-head tests. The Xeon E3-1225 v5 is the winner in ECC support and in its lower launch price, but those are not performance wins. For anyone choosing between these two based on the data, the i7-8665U is the faster processor, while the Xeon is the safer choice for ECC-dependent environments.