Intel Core i3-8100T vs Intel Core i7-8665U Comparison

The Intel Core i7-8665U is the clear benchmark victor over the Intel Core i3-8100T, winning all six head-to-head tests with a consistent performance margin. This outcome is driven by the i7-8665U’s Hyper-Threading and higher boost clock, which more than compensate for its lower base clock and drastically lower TDP. The i3-8100T, however, is not without merit; it offers a desktop socket, a larger die, and ECC memory support, making it a specialized alternative rather than a direct competitor.

Head-to-Head Benchmarks

The data is unambiguous: the Intel Core i7-8665U outperforms the Intel Core i3-8100T across every Cinebench test. The most substantial lead appears in Cinebench R15 single-core, where the i7-8665U scores 74 against the i3-8100T’s 63, a 17.5% advantage. This is a significant single-thread gap, indicating that the i7-8665U’s 4.80 GHz boost clock provides a tangible edge in lightly-threaded workloads.

Multi-core performance tells a similar story. In Cinebench R15 multicore, the i7-8665U scores 527 versus 450 for the i3-8100T, a 17.1% difference. This pattern repeats in Cinebench R20 multicore (2197 vs 1876) and Cinebench R23 multicore (5232 vs 4467), with the same 17.1% delta. The consistency across generations of the Cinebench test suggests a structural advantage rather than a workload-specific anomaly. The i7-8665U’s 8 threads versus the i3-8100T’s 4 threads are the primary driver, allowing better utilization of multi-threaded rendering tasks.

Single-core scores in newer tests also favor the i7-8665U. Cinebench R20 single-core shows 309 for the i7-8665U and 264 for the i3-8100T (17% delta), while Cinebench R23 single-core shows 738 versus 630 (17.1% delta). The i3-8100T’s inability to boost beyond its 3.10 GHz base clock is a clear handicap here, as the i7-8665U’s dynamic frequency scaling reaches much higher peaks. Benchmark results indicate that the i7-8665U is roughly 17% faster in every measured scenario, making it the unequivocal performance leader in this comparison.

Architecture Differences

The two processors come from different Intel generations and target different platforms. The Intel Core i7-8665U is built on Whiskey Lake (Whiskey Lake-U) with a 14 nm process node, while the Intel Core i3-8100T uses Coffee Lake, also on a 14 nm node. Both are 4-core parts, but the i7-8665U implements Hyper-Threading, doubling its thread count to 8, whereas the i3-8100T is limited to 4 threads. This is the most consequential architectural distinction, directly explaining the multi-core benchmark gap.

Clock speeds differ sharply. The i7-8665U has a base clock of 1900.00 MHz and a boost clock of 4.80 GHz, a wide frequency range designed for bursty mobile workloads. The i3-8100T has a fixed base clock of 3.10 GHz with no boost capability listed, prioritizing consistent performance over peak responsiveness. The i7-8665U’s higher boost clock gives it a decisive advantage in single-threaded tasks, despite its lower base frequency.

Cache configurations also diverge. Both share 64 KB L1 and 256 KB L2 per core, but the i7-8665U features 8 MB of shared L3 cache, while the i3-8100T has 6 MB. This additional cache can improve hit rates in data-heavy workloads. The i7-8665U supports DDR3 and DDR4 memory, whereas the i3-8100T supports only DDR4; both use a dual-channel memory bus with identical 38.4 GB/s bandwidth. The i3-8100T notably supports ECC memory, a feature absent on the i7-8665U, making it suitable for error-sensitive computing environments.

Physical specifications reinforce their different roles. The i7-8665U is a mobile chip on Intel BGA 1528 socket with a 15 W TDP, while the i3-8100T is a desktop chip on Intel Socket 1151 with a 35 W TDP. The i3-8100T also has a documented die size of 126 mm², a figure not provided for the i7-8665U. Integrated graphics differ as well: the i7-8665U carries UHD Graphics 620, while the i3-8100T uses UHD Graphics 630. Both are end-of-life products, with the i7-8665U releasing in September 2018 and the i3-8100T in April 2018.

The Verdict

The data points to the Intel Core i7-8665U as the superior processor for raw performance. It wins every benchmark by a consistent 17-17.5% margin, a decisive edge that stems from its Hyper-Threading and higher boost clock. Users prioritizing speed in both single- and multi-threaded applications should select the i7-8665U without hesitation. Its 8 MB L3 cache and broader memory support (DDR3 and DDR4) add further versatility.

However, the i3-8100T is not obsolete. Its ECC memory support is a distinctive feature that the i7-8665U lacks, making it the only choice here for systems requiring error-correcting memory. The i3-8100T also offers a desktop socket (Socket 1151), which may be preferable for builds where upgradeability or standard desktop cooling is a priority. Its 35 W TDP, while higher, is still modest for a desktop part.

The i7-8665U’s 15 W TDP is remarkable given its performance lead, indicating superior efficiency in the benchmark data. For mobile users or those building compact systems, the i7-8665U is the obvious pick. For desktop users needing ECC and a fixed clock, the i3-8100T serves a niche role. The verdict is clear: the i7-8665U wins on performance, while the i3-8100T wins on specific platform features.

FAQ

Q: Which processor is faster in multi-core rendering?

A: The Intel Core i7-8665U is faster, scoring 5232 in Cinebench R23 multicore compared to 4467 for the Intel Core i3-8100T, a 17.1% advantage.

Q: Does the Intel Core i3-8100T support ECC memory?

A: Yes, the i3-8100T supports ECC memory, while the i7-8665U does not. This is a key differentiator for error-sensitive workloads.

Q: What is the single-core performance difference?

A: The i7-8665U leads in Cinebench R23 single-core with a score of 738 versus 630 for the i3-8100T, a 17.1% delta.

Q: Which CPU has a higher TDP?

A: The i3-8100T has a TDP of 35 W, while the i7-8665U has a TDP of 15 W, making the i7-8665U significantly more power-efficient.

Q: Are both processors on the same process node?

A: Yes, both are manufactured on a 14 nm process node by Intel, though they use different architectures (Whiskey Lake for the i7-8665U, Coffee Lake for the i3-8100T).

Q: How many threads does each CPU have?

A: The i7-8665U has 8 threads (4 cores with Hyper-Threading), while the i3-8100T has 4 threads (4 cores without Hyper-Threading).

Where Each One Wins

The Intel Core i7-8665U wins in all performance-centric scenarios. Its 17.1% lead in multi-core benchmarks makes it the better choice for video editing, 3D rendering, and any parallel workload that can utilize more than 4 threads. Its 17.5% single-core advantage in Cinebench R15 also makes it superior for everyday responsiveness, office applications, and lightly-threaded games. The larger 8 MB L3 cache and dual memory support (DDR3 and DDR4) give it flexibility in legacy and modern systems. Furthermore, its 15 W TDP makes it ideal for ultrabooks, compact mini-PCs, and any build where heat and power draw are critical constraints.

The Intel Core i3-8100T wins in niche scenarios defined by its platform features. Its ECC memory support is a decisive advantage for workstations handling financial data, scientific computations, or file servers where memory errors are unacceptable. Its desktop Socket 1151 allows for easier installation, replacement, and potentially better cooling solutions compared to the i7-8665U’s BGA 1528 socket, which is soldered. The i3-8100T’s fixed 3.10 GHz clock ensures predictable performance without boost variability, which can be beneficial for real-time applications that require consistent timing. Its larger die size (126 mm²) may also indicate different thermal characteristics, though the data does not measure thermals directly.

Specification Differences

The two processors differ in several key specifications. The i7-8665U has a base clock of 1900.00 MHz and a boost clock of 4.80 GHz, while the i3-8100T has a base clock of 3.10 GHz and no boost clock. The i7-8665U has 8 threads versus 4 threads for the i3-8100T. TDP differs significantly: 15 W for the i7-8665U versus 35 W for the i3-8100T. Sockets are incompatible: Intel BGA 1528 for the i7-8665U versus Intel Socket 1151 for the i3-8100T. L3 cache is 8 MB for the i7-8665U and 6 MB for the i3-8100T. Memory support varies: the i7-8665U supports DDR3 and DDR4, while the i3-8100T supports only DDR4. ECC memory is supported on the i3-8100T but not the i7-8665U. Integrated graphics are UHD Graphics 620 for the i7-8665U and UHD Graphics 630 for the i3-8100T. Die size is listed as 126 mm² for the i3-8100T but is not provided for the i7-8665U. Release dates differ: the i7-8665U launched in September 2018, while the i3-8100T launched in April 2018. Launch MSRP is $409 for the i7-8665U and $117 for the i3-8100T. Both have 4 cores, 14 nm process nodes, dual-channel memory buses, and 38.4 GB/s memory bandwidth.