Intel Core i7-8665UE vs Intel Xeon E5645 Comparison

FAQ

Q: Which processor has more cores and threads?

A: The Intel Xeon E5645 has 6 cores and 12 threads, while the Intel Core i7-8665UE has 4 cores and 8 threads. The Xeon also carries a larger shared L3 cache at 12 MB versus 8 MB for the Core i7.

Q: How do their single-core scores compare in Cinebench R23?

A: The Xeon E5645 scores 591 in Cinebench R23 single-core, which is 1.5% ahead of the Core i7-8665UE's 582. Despite the Core i7's much higher boost clock, the two are nearly identical in this test.

Q: What is the difference in power consumption?

A: The Xeon E5645 has a TDP of 80 watts, while the Core i7-8665UE is rated at 15 watts. The Core i7 consumes substantially less power, reflecting its mobile design.

Q: Do both processors support ECC memory?

A: No. The Xeon E5645 supports ECC memory, while the Core i7-8665UE does not. The Xeon also uses triple-channel DDR3 memory, whereas the Core i7 uses dual-channel DDR3 or DDR4.

Q: Which processor has integrated graphics?

A: The Core i7-8665UE includes UHD Graphics 620, while the Xeon E5645 has no integrated graphics. This makes the Core i7 a more self-contained option for systems without a discrete GPU.

Q: What are their overall benchmark percentiles?

A: The Xeon E5645 sits at the 34th percentile among all CPUs, while the Core i7-8665UE sits at the 33rd percentile. Their average benchmark scores are 1211 and 1193, respectively, placing them in the same performance tier.

Architecture Differences

The Intel Xeon E5645 is built on the Westmere architecture, specifically Westmere-EP, using a 32 nm process. It contains 1,170 million transistors on a 239 mm² die. The Core i7-8665UE uses the Whiskey Lake architecture, specifically Whiskey Lake-U, on a 14 nm process. The database does not list transistor count or die size for the Core i7. The Xeon is a server and workstation part, while the Core i7 is a mobile processor.

The Xeon E5645 has 6 physical cores and 12 threads, with a base clock of 2.40 GHz and a boost clock of 2.67 GHz. The Core i7-8665UE has 4 cores and 8 threads, with a base clock of 1700.00 MHz and a boost clock of 4.40 GHz. The Core i7's boost clock is dramatically higher, but its base clock is far lower. The Xeon compensates with two additional cores and 12 MB of shared L3 cache versus 8 MB.

Memory support differs significantly. The Xeon uses DDR3 over a triple-channel memory bus and supports ECC memory. The Core i7 supports both DDR3 and DDR4 over a dual-channel bus, has no ECC support, and lists a memory bandwidth of 38.4 GB/s. The Xeon does not have a listed memory bandwidth in the database. PCIe support also differs: the Xeon uses Gen 2, while the Core i7 uses Gen 3 with 16 lanes available from the CPU.

The Core i7 includes UHD Graphics 620, while the Xeon has no integrated graphics. The Xeon uses Intel Socket 1366, while the Core i7 uses Intel BGA 1528. Both processors are end-of-life and have locked multipliers. The Xeon was released in 2010, while the Core i7 was released in 2018. The Core i7 has a launch MSRP of $409; the database lists no launch MSRP for the Xeon.

The Verdict

The benchmark data shows a remarkably close race. Across all six Cinebench tests, the Xeon E5645 wins every single one, but by margins of only 1.4% to 1.7%. The largest advantage is in Cinebench R15 single-core, where the Xeon leads by 1.7%. The most common margin is 1.5%, appearing in R20 multicore, R23 multicore, and R23 single-core. The Xeon also wins R15 multicore by 1.4% and R20 single-core by 1.6%.

For a user choosing between these two, the decision is not about raw performance, because the scores are nearly indistinguishable. The Xeon E5645 is the better pick for server or workstation environments that require ECC memory, a triple-channel memory bus, and a traditional socketed design. It also offers more cores and threads, which can help in workloads that scale with parallel resources, even if the benchmark deltas are small.

The Core i7-8665UE is the better pick for mobile or compact systems. Its 15 watt TDP is dramatically lower than the Xeon's 80 watts, it includes integrated graphics, and it supports newer PCIe Gen 3 connectivity. The Core i7 also supports DDR4 memory and reaches a much higher boost clock of 4.40 GHz, which may translate into responsive single-threaded behavior in real-world use, even though the recorded Cinebench single-core scores are essentially tied.

In short, the data says these two are performance equals in the measured Cinebench workloads. The Xeon wins all six recorded tests, but the differences are within a narrow band. The choice should be driven by platform needs: ECC and socketed server use favor the Xeon, while low power, integrated graphics, and mobile form factors favor the Core i7.

Specification Differences

The two processors differ in nearly every core specification. The Xeon E5645 has 6 cores and 12 threads, while the Core i7-8665UE has 4 cores and 8 threads. Base clock is 2.40 GHz for the Xeon versus 1700.00 MHz for the Core i7. Boost clock is 2.67 GHz for the Xeon versus 4.40 GHz for the Core i7. TDP is 80 watts for the Xeon versus 15 watts for the Core i7.

Cache sizes differ in L3 only. Both list 64 KB of L1 per core and 256 KB of L2 per core, but the Xeon has 12 MB of shared L3 while the Core i7 has 8 MB of shared L3. Memory support is DDR3 for the Xeon and DDR3, DDR4 for the Core i7. The Xeon uses triple-channel memory while the Core i7 uses dual-channel. The Core i7 lists a memory bandwidth of 38.4 GB/s; the Xeon does not.

ECC memory is supported by the Xeon but not the Core i7. PCIe generation is Gen 2 for the Xeon and Gen 3 for the Core i7, with the Core i7 specifying 16 lanes from the CPU. The Xeon has no integrated graphics, while the Core i7 includes UHD Graphics 620. Sockets are Intel Socket 1366 for the Xeon and Intel BGA 1528 for the Core i7. Architecture is Westmere for the Xeon and Whiskey Lake for the Core i7. Process node is 32 nm for the Xeon and 14 nm for the Core i7.

The Xeon has a listed transistor count of 1,170 million and a die size of 239 mm², while the Core i7 has no listed values for either field. Market segments are Server/Workstation for the Xeon and Mobile for the Core i7. Release dates are 2010 for the Xeon and 2018 for the Core i7. The Core i7 has a launch MSRP of $409, while the Xeon has no launch MSRP in the database. Both are end-of-life parts with locked multipliers.

Head-to-Head Benchmarks

The head-to-head results are consistent and one-sided. The Xeon E5645 wins all six tests, starting with Cinebench R15 multicore at 421 points against the Core i7-8665UE's 415, a 1.4% lead. In R15 single-core, the Xeon scores 59 to the Core i7's 58, a 1.7% margin. R20 multicore sees the Xeon at 1758, the Core i7 at 1732, a 1.5% lead. R20 single-core shows 248 versus 244, a 1.6% gap.

R23 multicore has the Xeon at 4187 and the Core i7 at 4124, a 1.5% margin. R23 single-core shows the Xeon at 591 and the Core i7 at 582, a 1.5% lead. Across the six tests, the Xeon's average wins by 1.5% or close to it, with no single test exceeding 1.7% in favor of the Xeon. The Core i7-8665UE never wins a single test, but its deficit never grows beyond 1.7% either.

The overall database averages reinforce this pattern. The Xeon E5645 has an average benchmark score of 1211, which places it exactly level with the Intel Core i3-7300T at 1211 and just ahead of the Xeon E5-1607 v3, which trails by 0.1%. The Core i7-8665UE has an average score of 1193, level with the Core i3-4170 and the AMD Athlon PRO 300U at 1193. The Xeon's nearest rivals all fall within a 0.2% band around 1211, while the Core i7's nearest rivals fall within 0.2% around 1193 as well.

The percentile ranks are adjacent, at 34 for the Xeon and 34 and 33 for the Core i7, making the Xeon 1% ahead in percentile terms. The recorded data shows that while the Core i7-8665UE has the higher boost clock by a wide margin on paper, the recorded Cinebench single-core scores do not reflect that advantage, with the Xeon winning by 1.5% in R23 single-core despite its much lower boost clock. Similarly, the Xeon wins multicore tests by 1.5% in R23 while having the higher core count, a 1.5% margin that is small given the 2-core difference in cores.

The data indicates that the Xeon E5645 is ahead in every measured workload, with the Core i7-8665UE trailing by 1.5% in the most recent R23 tests and the Xeon leading by 1.5% in the same test. The Xeon E5645 wins 6 out of 6 recorded benchmarks, with the Core i7-8665UE winning 0, a clean sweep for the Xeon.

The overall numbers in the database list the Xeon E5645 at 421 in R15 multicore and the Core i7-8665UE at 59 in the same test, with the Xeon ahead by 1.4% in R15 multicore and the Core i7-8665UE scoring 58 in R15 single-core, with the Xeon ahead by 1.7% in that test as well. The Xeon E5645 has 1,170 million transistors and a 239 mm² die size, with the Core i7-8665UE having no listed transistors in the database, making the Xeon ahead by 1.5% in R23 multicore at 4187 versus 4124. The Core i7-8665UE has a 38.4 GB/s memory bandwidth, with the Xeon E5645 having no listed memory bandwidth as listed in the database. The Xeon E5645 is at 34th percentile vs all CPUs, with the Core i7-8665UE at 33rd, with the Xeon ahead by 1.5% in R23 singlecore at 591 versus 582. The Core i7-8665UE has a launch MSRP of $409 as launch MSRP, with the Xeon E5645 having no launch MSRP listed, with the Xeon ahead by 1.5% in R20 multicore, 1758 to 1732. The Core i7-8665UE is a mobile segment part, with the Xeon E5645 is a server segment part.

Where Each One Wins

The Xeon E5645 wins every recorded benchmark, so it is the clear leader in raw Cinebench performance across all tested workloads. Its 1.5% margin in R23 multicore at 4187 to 4124 and the same 1.5% margin in R23 single-core at 591 to 582 make it the pick for environments where every point matters, such as server and workstation tasks. The Xeon's 6 core and 12 thread configuration, combined with its 12 MB L3 cache and triple-channel DDR3 support, positions it for workstation use cases that rely on sustained parallel throughput, as reflected in its 1.5% multicore wins across R15, 421 to 415, R20, 1758 to 1732, and R23, 4187 to 4124. ECC memory support further solidifies its role in error-sensitive server workloads, and its 32 nm process node and Gen 2 PCIe support are the platform traits of its era.

The Core i7-8665UE wins no benchmark tests, but it wins on platform characteristics. Its 15 watt TDP makes it suitable for fanless or ultraportable mobile designs, where the Xeon's 80 watt TDP would be impractical. Integrated UHD Graphics 620 eliminates the need for a discrete GPU in basic display tasks, while the Xeon requires external graphics hardware. The Core i7's support for DDR4 memory and its Gen 3 PCIe connectivity with 16 CPU lanes offer more modern I/O options, which matter for mobile systems with newer peripherals. Its 4.40 GHz boost clock is far above the Xeon's 2.67 GHz boost, and its 1700.00 MHz base clock is far below the Xeon's 2.40 GHz base, giving the Core i7 a wider frequency range for dynamic power management. The 8 MB L3 cache and dual-channel memory bus are smaller than the Xeon's 12 MB and triple-channel bus, but the Core i7's lower power profile and integrated graphics make it the natural fit for compact and mobile deployments.

In practice, the Xeon E5645 is the choice for server racks and workstations where ECC memory, triple-channel bandwidth, and a 6-core, 12-thread layout are required, even if the benchmark lead over the Core i7 is only 1.5% in R23 multicore. The Core i7-8665UE is the choice for thin-and-light laptops and embedded systems where the 15 watt TDP, integrated UHD Graphics 620, and DDR4 support outweigh the slight performance deficit, which never exceeds 1.7% in any recorded test. The data does not show a performance tier gap, only a platform gap, so the decision rests on the system's physical and electrical constraints rather than on measurable speed differences.