Which is better, Intel E5420 or Intel E8400?

E5420 is 77 1 quad-core, e8400 is 775 dual-core, and e5420 has good performance, but e5420 is a server processor, which needs hard modification (or pasting with an adapter) before it can be used on the 775 motherboard. E5420 has two versions: eo version and co version. If the eo version is not lit, the motherboard needs to brush microcode, and the co version can be lit directly. If you are upgrading an old computer and you don't know much about it, just buy a hard-changed, non-deleted co version from Taobao.