Both models
i7-4820K and
i5-3340M are based on
Ivy Bridge architecture.
"Ivy Bridge is the last Intel microarchitecture for which there is official driver support for Windows XP . It is made under 22 nm Tri-Gate transistor (""3D"") technology and is basically a Sandy Bridge shrink. It has PCI Express 3.0 support and RdRand instruction for security tasks."
Using the multithread performance as a reference, the i7-4820K gets a score of
134.1 k points while the i5-3340M gets
62.8 k points.
Summarizing, the
i7-4820K is
2.1 times faster than the
i5-3340M . To get a proper comparison between both models, take a look to the data shown below.