Core 2 Quad Q8400 vs Celeron 6305

The Core 2 Quad Q8400 packs 4 cores / 4 threads, while the Celeron 6305 offers 2 cores / 2 threads — the Core 2 Quad Q8400 has 2 more cores. Boost clocks reach 0.67 GHz on the Core 2 Quad Q8400 versus 1.8 GHz on the Celeron 6305 — a 91.5% clock advantage for the Celeron 6305. The Core 2 Quad Q8400 uses the Yorkfield (2007−2009) architecture (45 nm), while the Celeron 6305 uses Tiger Lake-U (2020−2021) (10 nm SuperFin). In PassMark, the Core 2 Quad Q8400 scores 2,076 against the Celeron 6305's 2,077 — a 0% lead for the Celeron 6305. Geekbench 6 single-core — the metric most relevant to gaming — records 369 vs 744, a 67.4% lead for the Celeron 6305 that directly translates to higher frame rates. Multi-core Geekbench: 1,155 vs 1,236 (6.8% advantage for the Celeron 6305). L3 cache: 0 kB on the Core 2 Quad Q8400 vs 4 MB on the Celeron 6305.

The Core 2 Quad Q8400 uses the LGA775 socket (PCIe 1.1), while the Celeron 6305 uses FCBGA1449 (PCIe 4.0) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR3 1333 MHz on the Core 2 Quad Q8400 versus DDR4-3200 on the Celeron 6305 — the Core 2 Quad Q8400 supports 199.9% faster memory, which can translate to measurable gains in memory-sensitive workloads. The Celeron 6305 supports up to 64 GB of RAM compared to 16 GB — 120% more capacity for professional workloads. Both feature 2-channel memory with ECC support. PCIe lanes: 0 (Core 2 Quad Q8400) vs 4 (Celeron 6305) — the Celeron 6305 offers 4 more lanes for additional GPUs or NVMe drives. Chipset compatibility: Intel P45,Intel G41,Intel Q45,Intel X48,Intel G31 (Core 2 Quad Q8400) and Tiger Lake-U (Celeron 6305).

Neither processor supports overclocking. Virtualization support: true (Core 2 Quad Q8400) vs VT-x, VT-d (Celeron 6305). The Celeron 6305 includes integrated graphics (UHD Graphics for 11th Gen), while the Core 2 Quad Q8400 requires a dedicated GPU. Primary use case: Core 2 Quad Q8400 targets Desktop, Celeron 6305 targets Budget. Direct competitor: Celeron 6305 rivals Pentium Gold 7505.

The Core 2 Quad Q8400 launched at $183 MSRP, while the Celeron 6305 debuted at $107. At current prices ($128 vs $80), the Celeron 6305 is $48 cheaper. In terms of value (PassMark points per dollar), the Core 2 Quad Q8400 delivers 16.2 pts/$ vs 26.0 pts/$ for the Celeron 6305 — making the Celeron 6305 the 46.2% better value option.