Core i5-4300U vs Core 2 Duo P8400

The Core i5-4300U packs 2 cores / 4 threads, matching the Core 2 Duo P8400's 2 cores. Boost clocks reach 2.9 GHz on the Core i5-4300U versus 2.26 GHz on the Core 2 Duo P8400 — a 24.8% clock advantage for the Core i5-4300U (base: 1.9 GHz vs 2.26 GHz). The Core i5-4300U uses the Haswell (2013−2015) architecture (22 nm), while the Core 2 Duo P8400 uses Penryn (2008−2011) (45 nm). In PassMark, the Core i5-4300U scores 2,482 against the Core 2 Duo P8400's 2,497 — a 0.6% lead for the Core 2 Duo P8400. L3 cache: 3 MB on the Core i5-4300U vs 3 MB L2 Cache on the Core 2 Duo P8400.

The Core i5-4300U uses the FCBGA1168 socket (PCIe 3.0), while the Core 2 Duo P8400 uses PGA478 (PCIe 1.1) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR3L-1600 on the Core i5-4300U versus 1066 on the Core 2 Duo P8400 — the Core 2 Duo P8400 supports 198.9% faster memory, which can translate to measurable gains in memory-sensitive workloads. The Core i5-4300U supports up to 16 GB of RAM compared to 8 — 66.7% more capacity for professional workloads. Both feature 2-channel memory with ECC support. PCIe lanes: 12 (Core i5-4300U) vs 0 (Core 2 Duo P8400) — the Core i5-4300U offers 12 more lanes for additional GPUs or NVMe drives. Chipset compatibility: HM86,HM87 (Core i5-4300U) and GM45,GS45,PM45 (Core 2 Duo P8400).

Virtualization support: Yes (Core i5-4300U) vs true (Core 2 Duo P8400). The Core i5-4300U includes integrated graphics (Intel HD Graphics 4400), while the Core 2 Duo P8400 requires a dedicated GPU. Direct competitor: Core 2 Duo P8400 rivals Turion II Ultra M600.