Core i5-2500K vs Core i3-8140U

The Core i5-2500K packs 4 cores / 4 threads, while the Core i3-8140U offers 2 cores / 4 threads — the Core i5-2500K has 2 more cores. Boost clocks reach 3.7 GHz on the Core i5-2500K versus 3.9 GHz on the Core i3-8140U — a 5.3% clock advantage for the Core i3-8140U (base: 3.3 GHz vs 2.1 GHz). The Core i5-2500K is built on the Sandy Bridge (2011−2013) architecture. In PassMark, the Core i5-2500K scores 4,141 against the Core i3-8140U's 4,227 — a 2.1% lead for the Core i3-8140U. Geekbench 6 single-core — the metric most relevant to gaming — records 684 vs 1,225, a 56.7% lead for the Core i3-8140U that directly translates to higher frame rates. L3 cache: 6 MB (total) on the Core i5-2500K vs 4 MB Intel® Smart Cache on the Core i3-8140U.

The Core i5-2500K uses the LGA1155 socket (PCIe 2.0), while the Core i3-8140U uses FCBGA1528 (PCIe 3.0) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR3-1333 on the Core i5-2500K versus DDR4-2400 on the Core i3-8140U — the Core i3-8140U supports 28.6% faster memory, which can translate to measurable gains in memory-sensitive workloads. The Core i3-8140U supports up to 64 GB of RAM compared to 32 GB — 66.7% more capacity for professional workloads. Both feature 2-channel memory with ECC support. Both provide 16 PCIe lanes.

Only the Core i5-2500K has an unlocked multiplier for overclocking — a significant advantage for enthusiasts seeking extra performance. Virtualization support: VT-x (Core i5-2500K) vs VT-x, VT-d, EPT (Core i3-8140U). Both include integrated graphics — HD Graphics 3000 (Core i5-2500K) and UHD Graphics 620 (Core i3-8140U) — useful as a fallback for troubleshooting or display output without a dedicated GPU. Primary use case: Core i5-2500K targets Gaming, Core i3-8140U targets Mainstream Laptop. Direct competitor: Core i5-2500K rivals FX-6300; Core i3-8140U rivals Ryzen 3 3300U.