Celeron 6305 vs Core 2 Quad Q8400

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

The Celeron 6305 uses the FCBGA1449 socket (PCIe 4.0), while the Core 2 Quad Q8400 uses LGA775 (PCIe 1.1) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR4-3200 on the Celeron 6305 versus DDR3 1333 MHz on the Core 2 Quad Q8400 — 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: 4 (Celeron 6305) vs 0 (Core 2 Quad Q8400) — the Celeron 6305 offers 4 more lanes for additional GPUs or NVMe drives. Chipset compatibility: Tiger Lake-U (Celeron 6305) and Intel P45,Intel G41,Intel Q45,Intel X48,Intel G31 (Core 2 Quad Q8400).

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

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