Intel Core i5-8259U vs Intel Core i7-8705G Comparison

Head-to-Head Benchmarks

The recorded data shows a clear overall winner in this comparison: the Intel Core i5-8259U takes 7 of the 8 benchmark matchups, with the Intel Core i7-8705G claiming only a single victory. The most decisive result comes in Geekbench single-core, where the i7-8705G posts a score of 1277 against 1207 for the i5-8259U, a 5.5% margin in favor of the Kaby Lake part. That is the largest delta in either direction across the entire benchmark suite.

Beyond that single-core Geekbench result, the i5-8259U leads in every other test. In Geekbench multi-core, the i5-8259U scores 4168 against 3968 for the i7-8259U's rival, a 5% advantage. The Cinebench results follow a consistent pattern with smaller but consistent deltas. In Cinebench R15 multi-core, the i5-8259U scores 667 versus 651, a 2.5% win. The single-core variant of the same test shows 94 against 91, a 3.3% edge. Cinebench R20 repeats the trend: 2781 for the i5-8259U against 2714 for the i7-8705G, another 2.5% margin. The R20 single-core test shows 392 against 383, a 2.3% difference. Cinebench R23 follows with 6622 versus 6464, a 2.4% delta, and the R23 single-core result is 934 against 912, also a 2.4% delta.

The data indicates that the i5-8259U's multi-core advantage is steady across all three Cinebench generations, ranging from 2.4% to 2.5%. The single-core Cinebench deltas are slightly narrower, from 2.3% to 3.3%, while the Geekbench multi-core gap widens to 5%. The only reversal is the Geekbench single-core test, where the i7-8705G's 1277 score beats the i5-8259U's 1207 by 5.5%. This suggests the i7-8705G has a measurable single-thread edge in at least one workload, but the i5-8259U compensates with superior performance in the remaining seven tests.

Looking at average benchmark scores, the i5-8259U sits at 2108, which places it in the 46th percentile of all CPUs in the database. Its closest rival, the Intel Core i5-8500T, scores 2110, a delta of -0.1% relative to the i5-8259U. The AMD Ryzen 5 PRO 2400G trails at 2101, a 0.3% difference in favor of the i5-8259U. The Intel Xeon E-2224G records 2117, -0.4% versus the i5-8259U, and the Intel Core i3-8350K scores 2096, a 0.6% edge for the i5-8259U. The i7-8705G averages 2058 overall, also in the 46th percentile. Its nearest rival is the Intel Core i3-10105T at 2058 (0% delta), with the AMD Ryzen 5 3400G at 2059 (-0.1%), the AMD Ryzen 3 3100 at 2055 (0.2%), and the Intel Xeon E3-1585 v5 at 2067 (-0.4%). The gap between the two processors in average score is 50 points, a 2.4% advantage for the i5-8259U.

FAQ

Q: Which processor wins more benchmark tests?

A: The Intel Core i5-8259U wins 7 out of 8 head-to-head benchmarks. The Intel Core i7-8705G wins only 1 test, Geekbench single-core.

Q: What is the largest performance difference between the two?

A: The largest delta is in Geekbench single-core, where the i7-8705G beats the i5-8259U by 5.5% (1277 versus 1207). The largest win for the i5-8259U is in Geekbench multi-core at 5% (4168 versus 3968).

Q: How do they compare in Cinebench R23?

A: The i5-8259U scores 6622 in multi-core and 934 in single-core. The i7-8705G scores 6464 and 912 respectively. The i5-8259U leads by 2.4% in both tests.

Q: Do both processors have the same number of cores and threads?

A: Yes, both have 4 cores and 8 threads.

Q: What are their average benchmark scores?

A: The i5-8259U has an average benchmark score of 2108, while the i7-8705G averages 2058. Both sit in the 46th percentile of all CPUs in the database.

Q: Which processor has higher clock speeds?

A: The i7-8705G has a base clock of 3.10 GHz and a boost clock of 4.10 GHz, both higher than the i5-8259U's 2.30 GHz base and 3.80 GHz boost.

Architecture Differences

The two processors come from different Intel architectures despite sharing the same 14 nm process node. The i5-8259U is built on Coffee Lake, specifically the Coffee Lake-U generation, while the i7-8705G uses Kaby Lake, designated as Kaby Lake-G. Both are manufactured by Intel on 14 nm, but the die sizes differ slightly: the i5-8259U measures 126 mm², while the i7-8705G is 125 mm².

The i7-8705G carries a larger L3 cache at 8 MB shared, compared to 6 MB shared for the i5-8259U. Both processors feature 64 KB of L1 cache per core and 256 KB of L2 cache per core, so the cache hierarchy is identical at the first two levels. The integrated graphics differ substantially. The i5-8259U pairs its CPU with Iris Pro Plus 655, while the i7-8705G uses Intel HD Graphics 630. This is a notable architectural split, as the i5-8259U's graphics solution is positioned as a higher-tier integrated GPU within Intel's lineup of that era.

The PCIe configuration also differs. The i5-8259U supports PCIe Gen 3 with 16 lanes (CPU only), while the i7-8705G supports PCIe Gen 3 with only 8 lanes (CPU only). This difference in lane count can affect bandwidth for discrete GPUs or other high-throughput devices. Memory support is identical on paper: both use DDR4 with dual-channel memory bus and 38.4 GB/s memory bandwidth. Neither supports ECC memory. Both processors are end-of-life mobile parts with locked multipliers.

The socket types are different as well. The i5-8259U uses Intel BGA 1526, while the i7-8705G uses Intel BGA 2270. The i5-8259U was released on 2018-04-04, whereas the i7-8705G was released earlier on 2018-01-06. The part numbers are SRCKBSRCUU for the i5-8259U and SR3RK for the i7-8705G.

Specification Differences

The clock speed gap is the most visible spec difference. The i5-8259U runs at 2.30 GHz base and 3.80 GHz boost, while the i7-8705G runs at 3.10 GHz base and 4.10 GHz boost. That is a 0.80 GHz higher base clock and a 0.30 GHz higher boost clock for the i7-8705G. The thermal design power (TDP) also diverges sharply: the i5-8259U is rated at 28 W, while the i7-8705G is rated at 65 W. This explains why the i7-8705G can sustain higher clocks despite the same core and thread count.

The L3 cache differs as noted: 6 MB shared on the i5-8259U versus 8 MB shared on the i7-8705G. The integrated graphics are different (Iris Pro Plus 655 versus Intel HD Graphics 630). PCIe lane count differs (16 lanes versus 8 lanes). The sockets are different (BGA 1526 versus BGA 2270). The launch MSRP for the i5-8259U is $320; the i7-8705G has no recorded launch MSRP in the database. Both are end-of-life mobile processors with 4 cores and 8 threads, both locked, both with DDR4 dual-channel memory at 38.4 GB/s bandwidth, and both without ECC support.

Where Each One Wins

The i5-8259U is the recommended choice for users prioritizing sustained multi-threaded workloads across Cinebench generations. Its wins in R15 multi-core (667 versus 651), R20 multi-core (2781 versus 2714), R23 multi-core (6622 versus 6464) all show a consistent 2.4% to 2.5% advantage. The Geekbench multi-core result reinforces this, with the 4168 score beating the i7-8705G's 3968 by a full 5%. For mixed workloads that include lighter multi-threaded rendering where the i5-8259U edges ahead in every Cinebench test, the i5-8259U consistently delivers the higher score. The i5-8259U also wins all three Cinebench single-core tests, with a 3.3% margin in R15 single-core and a 2.3% margin in R20 single-core.

The i7-8705G's only benchmark win is in Geekbench single-core, where its 1277 score beats the i5-8259U's 1207 by 5.5%. In a single-threaded Geekbench scenario, the i7-8705G is the better part. The higher base clock of 3.10 GHz and boost clock of 4.10 GHz likely contribute to this result, as does the larger 8 MB L3 cache. However, its 65 W TDP is over twice the i5-8259U's 28 W rating, which suggests the i7-8705G needs more power to achieve those clocks. For users who value the Geekbench single-core score above all other metrics, the i7-8705G is the winner. For every other benchmark in the database, the i5-8259U takes the lead.

The i5-8259U also offers more PCIe lanes (16 versus 8), which could matter for configurations with multiple high-bandwidth devices. The i7-8705G has a higher base and boost clock and more L3 cache, but those advantages translate to only one benchmark win. The i5-8259U's lower TDP of 28 W versus 65 W may make it easier to cool in thin mobile chassis, though both are end-of-life parts. In terms of raw benchmark performance, the i5-8259U is the stronger overall processor, with a 2.4% advantage in average score and wins in 7 of 8 head-to-head tests. The i7-8705G remains relevant only for workloads that mirror the Geekbench single-core test pattern, where it demonstrates a 5.5% lead.