Intel Core i5-1345U vs Intel Core i7-8700K Comparison

The Intel Core i5-1345U and Intel Core i7-8700K represent two very different design philosophies from Intel: a modern, power-efficient mobile processor against an older, high-power desktop part. The benchmark data reveals a fascinating split, with the newer mobile chip winning the majority of head-to-head tests, while the older desktop chip demonstrates its strength in specific sustained workloads. This analysis breaks down the data to show exactly where each processor excels and where it falls behind.

Head-to-Head Benchmarks

The most striking result in the benchmark suite is the i5-1345U’s commanding 47.2% lead over the i7-8700K in Cinebench R15 single-core scoring, with 240 points against 163. This massive delta in a single-threaded test highlights the generational leap in Intel’s core architecture, as the mobile chip’s newer design delivers significantly higher instructions-per-clock. The i5-1345U also wins Cinebench R20 single-core by 2% (697 vs 683) and Cinebench R23 single-core by 6% (1724 vs 1627), showing that the single-thread advantage persists across all versions of the benchmark.

Multi-core results tell a more nuanced story. In Cinebench R15 multi-core, the i5-1345U wins by 12.9% (1311 vs 1161), and in R20 it wins by a narrower 2.1% (4942 vs 4841). However, the i7-8700K strikes back decisively in Cinebench R23 multi-core, delivering a 33% victory with a score of 11527 against the i5-1345U’s 7724. This dramatic reversal suggests that the R23 test, which runs longer and is more demanding, allows the i7-8700K’s higher sustained power delivery to overcome the architectural efficiency of the i5-1345U.

Looking at the PassMark suite, the i5-1345U dominates several categories. The data encryption test shows a 115.4% advantage for the i5-1345U (10288 vs 4776), indicating that modern instruction set extensions provide a massive boost in cryptographic workloads. The mobile chip also wins floating point math by 25.9% (35939 vs 28538), integer math by 15.2% (52847 vs 45892), and prime number finding by 20.5% (47 vs 39). In the PassMark multi-thread test, the i5-1345U leads by 6.9% (14511 vs 13576), and even in physics simulation it edges ahead by 0.9% (818 vs 811).

The i7-8700K’s wins in the PassMark suite are equally notable. It beats the i5-1345U by 17.6% in data compression (198951 vs 164005), by 32.1% in extended instructions (13514 vs 9178), and by 25.3% in random string sorting (25270 vs 18888). These results point to workloads where the i7-8700K’s higher base clock and desktop-class power envelope allow it to sustain throughput that the mobile chip cannot match over extended periods.

Overall, the i5-1345U wins 13 of the 17 head-to-head benchmark comparisons, while the i7-8700K wins only 4. The average benchmark score for the i5-1345U is 19411, compared to 19238 for the i7-8700K, a difference of 0.9% in favor of the mobile chip. Both processors sit at the 73rd percentile among all CPUs, indicating they are closely matched in overall performance despite their contrasting architectures.

Architecture Differences

The architectural gap between these two processors is substantial. The i5-1345U is built on Intel’s Raptor Lake architecture, specifically Raptor Lake-U, using a 10 nm process node. The i7-8700K uses the older Coffee Lake architecture on a 14 nm process node. This process difference is fundamental, as the 10 nm node allows for tighter transistor packing and improved power efficiency per clock cycle.

The core configurations differ significantly. The i5-1345U features 10 cores and 12 threads, while the i7-8700K has 6 cores and 12 threads. Despite having fewer cores, the i7-8700K consumes far more power, with a TDP of 95 watts compared to the i5-1345U’s 15 watts. The i5-1345U compensates for its lower power envelope with a base clock of 1600 MHz and a boost clock of 4700 MHz, while the i7-8700K operates at a base clock of 3700 MHz and the same 4700 MHz boost.

Cache hierarchies are also structured differently. The i5-1345U has 80 KB of L1 cache and 1.25 MB of L2 cache per core, while the i7-8700K has 64 KB of L1 and 256 KB of L2 per core. Both share 12 MB of L3 cache, though the i5-1345U’s is shared across its 10 cores while the i7-8700K’s is shared across 6 cores, giving the desktop chip a larger effective pool per core.

Memory support diverges as well. The i5-1345U supports both DDR4 and DDR5 memory, while the i7-8700K is limited to DDR4. The i7-8700K does list a memory bandwidth of 42.7 GB/s, a figure not provided for the i5-1345U. The mobile chip uses Intel BGA 1744 socket, whereas the desktop part uses Intel Socket 1151. The i7-8700K also has a larger die size at 154 mm², while the i5-1345U’s die size is not listed.

Where Each One Wins

The i5-1345U is the clear winner in single-threaded performance and modern instruction-heavy workloads. Its 47.2% lead in Cinebench R15 single-core and 25.6% lead in PassMark single-thread (3415 vs 2720) make it the better choice for applications that rely on quick, responsive single-core tasks. The 115.4% advantage in data encryption and 25.9% lead in floating point math indicate strength in cryptography and scientific calculations that benefit from newer instruction sets. The i5-1345U also wins in integer math and prime number finding, suggesting it handles general arithmetic and logic-heavy code better.

The i7-8700K wins in sustained, power-hungry tasks that can utilize its higher base clock and desktop power budget. Its 33% victory in Cinebench R23 multi-core is the largest margin in the entire benchmark set, demonstrating that long-duration multi-threaded rendering favors the desktop chip. The i7-8700K also excels in data compression, extended instructions, and random string sorting, which are memory-intensive and benefit from the desktop platform’s higher memory bandwidth and consistent clock speeds.

For mixed-use scenarios, the i5-1345U’s win in PassMark multi-thread (14511 vs 13576) and physics simulation (818 vs 811) shows it can handle general multi-threaded tasks effectively despite its lower TDP. However, the i7-8700K’s pattern of winning in workloads that stress sustained throughput suggests it is better suited for batch processing and heavy compilation tasks where the system can run at full load for extended periods.

Specification Differences

The specification tables reveal several key differences between the two processors. The i5-1345U has 10 cores and 12 threads, while the i7-8700K has 6 cores and 12 threads. Base clocks differ sharply: 1600 MHz for the mobile chip versus 3700 MHz for the desktop chip, though both boost to 4700 MHz. The TDP is dramatically different at 15 watts for the i5-1345U and 95 watts for the i7-8700K.

The i5-1345U uses a 10 nm process node and the i7-8700K uses 14 nm. The i5-1345U has 80 KB L1 and 1.25 MB L2 per core, while the i7-8700K has 64 KB L1 and 256 KB L2 per core. Both have 12 MB of shared L3 cache. Memory support differs, with the i5-1345U accepting DDR4 and DDR5, while the i7-8700K only supports DDR4. The i7-8700K lists a memory bandwidth of 42.7 GB/s, which the i5-1345U does not specify.

The i5-1345U uses Intel BGA 1744 socket and has a launch MSRP of $309, while the i7-8700K uses Intel Socket 1151 and had a launch MSRP of $359. The i7-8700K is unlocked for overclocking, while the i5-1345U is not. The i5-1345U features Iris Xe Graphics 80EU, while the i7-8700K has UHD Graphics 630. The i5-1345U uses PCIe Gen 4 with 8 lanes, while the i7-8700K uses PCIe Gen 3 with 16 lanes. The i5-1345U is marked as Active production status and released in 2023-01-03, while the i7-8700K is End-of-life and released in 2017-10-04.

FAQ

Q: Which processor has a higher single-core performance?

A: The Intel Core i5-1345U wins all single-core benchmarks, with a 47.2% lead in Cinebench R15 (240 vs 163), a 2% lead in Cinebench R20 (697 vs 683), a 6% lead in Cinebench R23 (1724 vs 1627), and a 25.6% lead in PassMark single-thread (3415 vs 2720).

Q: How do the two chips compare in multi-core performance?

A: The i5-1345U wins Cinebench R15 multi-core by 12.9% (1311 vs 1161) and R20 by 2.1% (4942 vs 4841), but the i7-8700K wins Cinebench R23 multi-core by 33% (11527 vs 7724). The i5-1345U also wins PassMark multi-thread by 6.9% (14511 vs 13576).

Q: What is the core and thread count difference?

A: The i5-1345U has 10 cores and 12 threads, while the i7-8700K has 6 cores and 12 threads, meaning both support 12 threads but the i5-1345U has more physical cores.

Q: Which processor supports newer memory types?

A: The i5-1345U supports both DDR4 and DDR5 memory, while the i7-8700K only supports DDR4. The i7-8700K does list a memory bandwidth of 42.7 GB/s, which is not specified for the i5-1345U.

Q: How does the power consumption compare?

A: The i5-1345U has a TDP of 15 watts, while the i7-8700K has a TDP of 95 watts, making the mobile chip significantly more power-efficient.

Q: Which processor has a higher average benchmark score?

A: The i5-1345U has an average benchmark score of 19411, while the i7-8700K has 19238, a difference of 0.9% in favor of the i5-1345U. Both are at the 73rd percentile among all CPUs.

The Verdict

The data clearly shows that the Intel Core i5-1345U is the superior processor for the majority of workloads, winning 13 out of 17 head-to-head benchmarks. Its dominance in single-core performance, data encryption, and floating-point math makes it the better choice for users who prioritize responsiveness and modern application acceleration. The 47.2% lead in Cinebench R15 single-core and 115.4% lead in encryption are simply too large to ignore for general computing tasks.

However, the Intel Core i7-8700K remains relevant for specific use cases. Its 33% victory in Cinebench R23 multi-core and 32.1% lead in extended instructions indicate it is better suited for prolonged, power-hungry rendering or computational workloads where the desktop platform’s sustained performance can be fully utilized. Users who run long multi-threaded batch jobs may find the i7-8700K delivers better throughput despite its older architecture.

For mobile users or those building compact systems, the i5-1345U’s 15-watt TDP versus the i7-8700K’s 95-watt TDP makes it the only practical choice. The i5-1345U also offers newer memory support and a more modern integrated GPU. The i7-8700K’s unlocked multiplier and larger PCIe lane count (16 vs 8) may appeal to desktop enthusiasts, but its end-of-life status and older process node are significant drawbacks. Overall, the i5-1345U is the more versatile and future-ready processor based on the benchmark evidence.