Maximum PC

I thought that one advantage of the X58 chipset and Core i7-9xx CPUs was that they provided 6.4GT/s data speed with "QPI" (versus the P55 chipset which uses the slower DMI). However, on page 38 of the November 2010 issue of MaximumPC, I read that "the QPI was set for 6,407MHz" for overclocking a Core i5-760 with a P55 chipset.

Would someone please educate me on the differences and/or similarities of the "QPI" term with respect to the P55 and X58 chipsets? Is "QPI" with the X58 chipset and Core i7-9xx CPUs any advantage for which one would want to pay extra (versus the P55 chipset and its CPUs)?

The i5s and P55 Chipset DO use QPI. In the P45 & older chipsets, they used to connect to the memory & PCI-express slots via the frontside bus. In the Core i5/i7, the CPU is connected to the memory via 1 QPI interface and PCI-express is built-in to the CPU die (thus the reason for the low total bandwidth in the p55 chipset). The P55 chipset is then connected to the south bridge (ICH 10) via a DMI interface. On the 1366 platform, EVERYTHING is connected together via QPI interfaces. One to the memory, one to the X58 north bridge, one to the ICH 10 south bridge and one to PCI-express for a total of 4. Hope that clears it up some for you.

Thank you, Gutter96, for your good explanation of where QPI interfaces are used with both the X58 and P55 chipsets.

I was previously misled and confused by block diagrams of these systems, in which QPI was labelled on only one interface (from Core i7-9xx CPU to X58 chipset, TrustedReviews, July 2009).