Intel Core i5-1335U vs Intel Core i7-8700K Comparison

The Intel Core i7-8700K and Intel Core i5-1335U are separated by six years of silicon evolution, yet neither is a clean sweep over the other. The data shows a clear split: the older desktop chip wins 4 of 17 head-to-head benchmarks, while the newer mobile processor takes 13. The i7-8700K dominates in sustained multi-core rendering and specific data-processing tasks, whereas the i5-1335U leads in nearly every single-threaded test and several integer-heavy workloads. This is not a simple "newer is better" story—it is a tale of architectural priorities, where a 95W desktop part with fewer, faster cores trades blows with a 15W mobile part that leans on efficiency and instruction-level parallelism.

Where Each One Wins

The Intel Core i7-8700K is the champion of heavy, sustained multi-core workloads that scale with cache and raw throughput. Its most decisive victory comes in Cinebench R23 multi-core, where it scores 11527 against the i5-1335U's 8889.5—a 29.7% advantage. The desktop part also dominates data compression (198951 vs 159593, a 24.7% lead) and extended instruction workloads (13514 vs 8974, a 50.6% lead). Random string sorting is another clear win: 25270 vs 17953, a 40.8% margin. These are tasks that reward the i7-8700K's 12 MB of shared L3 cache and its 6 cores running at a 4.70 GHz boost clock, unconstrained by thermal limits.

The Intel Core i5-1335U wins everywhere else, and it wins big in single-threaded performance. In Cinebench R15 single-core, it posts 238 versus 163—a 31.5% lead. PassMark single-thread shows 3336 versus 2720, an 18.5% margin. The mobile chip also excels in data encryption (10009 vs 4776, a 52.3% lead) and floating-point math (35176 vs 28538, an 18.9% edge). Even in multi-threaded PassMark, it edges ahead: 14281 vs 13576, a 4.9% win. The pattern is consistent: the i5-1335U wins when the workload is short, bursty, or benefits from its 10 cores and higher per-core efficiency, while the i7-8700K wins when the task is sustained and cache-hungry.

The division is stark. The i7-8700K is a desktop workhorse for rendering and data shuffling; the i5-1335U is a mobile all-rounder that wins most benchmarks but loses the longest, most demanding tests. Users should not expect the older chip to be obsolete—it holds its own in specific niches.

Architecture Differences

The two processors come from different Intel families and design philosophies. The i7-8700K is built on Coffee Lake, a 14 nm process, and uses a monolithic 6-core design with 12 threads. Each core has 64 KB of L1 and 256 KB of L2 cache, with 12 MB of shared L3. It runs at a 3.70 GHz base clock and boosts to 4.70 GHz, with a 95W TDP. The chip is socketed (Intel Socket 1151), supports DDR4 memory on a dual-channel bus with 42.7 GB/s bandwidth, and offers PCIe Gen 3 with 16 CPU lanes. It includes UHD Graphics 630 integrated graphics. Launched on 2017-10-04, it is end-of-life and had a launch MSRP of $359. It has an unlocked multiplier for overclocking.

The i5-1335U is Raptor Lake-U, built on a 10 nm process, and uses a hybrid architecture with 10 cores and 12 threads—likely a mix of performance and efficiency cores, though the data does not specify the split. Base clock is listed at 1300.00 MHz, boosting to 4.60 GHz, with a dramatically lower 15W TDP. It is a mobile BGA 1744 package, supports both DDR4 and DDR5 memory on a dual-channel bus, and provides PCIe Gen 4 with 8 CPU lanes. Its integrated graphics are Iris Xe Graphics 80EU. Launched on 2023-01-03, it remains active and had a launch MSRP of $340. The multiplier is locked. Cache configuration differs: L1 is 80 KB per core, L2 is 1.25 MB per core, but L3 remains 12 MB shared—same as the i7-8700K.

The process node difference (14 nm vs 10 nm) explains much of the efficiency gap. The i5-1335U delivers comparable or better single-thread performance at a fraction of the power. The i7-8700K counters with higher boost clocks and a larger memory bandwidth figure (42.7 GB/s vs null for the i5), which supports its cache-heavy wins. The socket and market segment differences are fundamental: one is a desktop part, the other a mobile part. Neither supports ECC memory.

Head-to-Head Benchmarks

The largest single win belongs to the i5-1335U in PassMark data encryption, where it scores 10009 against 4776—a 52.3% lead. This is a massive margin, suggesting the newer chip's integrated encryption instructions are far more efficient. The i7-8700K's biggest win is PassMark extended instructions at 50.6% (13514 vs 8974), followed by random string sorting at 40.8% (25270 vs 17953) and Cinebench R23 multi-core at 29.7% (11527 vs 8889.5).

In Cinebench R15, the i5-1335U wins both multi-core (1464 vs 1161, a 20.7% lead) and single-core (238 vs 163, a 31.5% lead). The R20 results are closer: the i5 wins multi-core by just 1.9% (4935 vs 4841) and single-core by 1.9% (696 vs 683). The R23 single-core test shows the i5 ahead by 3.4% (1684.5 vs 1627). PassMark integer math favors the i5 by 10.4% (51244 vs 45892), floating-point math by 18.9% (35176 vs 28538), and prime number finding by 18.7% (48 vs 39). The i5 also wins PassMark physics by 3.1% (837 vs 811) and multi-thread by 4.9% (14281 vs 13576).

Notably, the i7-8700K wins all four of its benchmarks by substantial margins, while the i5-1335U wins many of its tests by smaller single-digit percentages. This suggests the i7-8700K is not merely slower—it is specialized for long-running, cache-heavy workloads where its 12 MB L3 and higher TDP allow sustained performance. The i5-1335U wins on efficiency and burst performance, but its advantages shrink in longer multi-core tests like Cinebench R23, where the i7-8700K's lead is nearly 30%.

FAQ

Q: Which CPU is faster in Cinebench R23 multi-core?

A: The Intel Core i7-8700K wins decisively, scoring 11527 versus the i5-1335U's 8889.5, a 29.7% advantage.

Q: Is the i5-1335U better in single-threaded performance?

A: Yes, it wins every single-threaded benchmark. The largest margin is Cinebench R15 single-core (238 vs 163, a 31.5% lead), and PassMark single-thread shows 3336 vs 2720, an 18.5% edge.

Q: How do they compare in data encryption?

A: The i5-1335U dominates, scoring 10009 in PassMark data encryption versus the i7-8700K's 4776—a 52.3% lead.

Q: What explains the i7-8700K's wins?

A: The data shows it wins in data compression (198951 vs 159593, 24.7% lead), extended instructions (13514 vs 8974, 50.6% lead), and random string sorting (25270 vs 17953, 40.8% lead). These are tasks that benefit from its 12 MB shared L3 cache and 4.70 GHz boost clock.

Q: Which CPU has more cores?

A: The i5-1335U has 10 cores versus the i7-8700K's 6 cores, but both have 12 threads.

Q: Are they on the same socket?

A: No. The i7-8700K uses Intel Socket 1151 (desktop), while the i5-1335U uses Intel BGA 1744 (mobile).

Specification Differences

| Specification | Intel Core i7-8700K | Intel Core i5-1335U |

|---|---|---|

| Cores | 6 | 10 |

| Threads | 12 | 12 |

| Base Clock | 3.70 GHz | 1300.00 MHz |

| Boost Clock | 4.70 GHz | 4.60 GHz |

| TDP | 95W | 15W |

| Socket | Intel Socket 1151 | Intel BGA 1744 |

| Architecture | Coffee Lake | Raptor Lake |

| Codename | Coffee Lake | Raptor Lake-U |

| Process Node | 14 nm | 10 nm |

| Die Size | 154 mm² | null |

| L1 Cache | 64 KB (per core) | 80 KB (per core) |

| L2 Cache | 256 KB (per core) | 1.25 MB (per core) |

| L3 Cache | 12 MB (shared) | 12 MB (shared) |

| Memory Support | DDR4 | DDR4, DDR5 |

| Memory Bandwidth | 42.7 GB/s | null |

| PCIe | Gen 3, 16 Lanes (CPU only) | Gen 4, 8 Lanes (CPU only) |

| Integrated Graphics | UHD Graphics 630 | Iris Xe Graphics 80EU |

| Market Segment | Desktop | Mobile |

| Production Status | End-of-life | Active |

| Release Date | 2017-10-04 | 2023-01-03 |

| Launch MSRP | $359 | $340 |

| Multiplier Unlocked | true | false |

| Part Number | SR3QRQNMK | SRMEX |

The table highlights the generational leap: the i5-1335U has more cores, a smaller process node, and supports newer memory standards, but the i7-8700K offers higher boost clock, more PCIe lanes, and a defined memory bandwidth figure. The i7-8700K is also unlocked for overclocking, a feature absent on the i5-1335U.

The Verdict

The data points to a clear choice based on workload and platform. For desktop users running sustained multi-core rendering, data compression, or extended instruction sets, the Intel Core i7-8700K is the pick. It wins Cinebench R23 multi-core by 29.7%, data compression by 24.7%, and extended instructions by 50.6%. Its 95W TDP and 4.70 GHz boost allow it to sustain performance in these cache-heavy tasks, despite being six years older.

For mobile users or those prioritizing single-threaded speed, encryption, and integer math, the Intel Core i5-1335U is the winner. It takes 13 of 17 benchmarks, including all single-threaded tests, data encryption by 52.3%, and floating-point math by 18.9%. Its 15W TDP and 10-core design make it suitable for laptops, and its active production status means it remains a current option.

The i7-8700K is not obsolete—it is specialized. The i5-1335U is the generalist that wins more tests but loses the longest ones. Choose the i7-8700K for a desktop workstation focused on rendering and data processing; choose the i5-1335U for a mobile platform where single-thread burst performance and efficiency are paramount. Both chips sit at the 73rd percentile of all CPUs, but they achieve that ranking through entirely different strengths.