QPI and PCI Express

Intel connects the execution cores, memory controller and PCI-E controller via internal QPI buses. The bus that connects the memory sockets to the CPU socket is also a QPI link, normally called the QPI Link. As with LGA1366, the QPI Link is derived from the Base Clock and the memory strap multiplier.

As there are no 'true' QPI links external to a Lynnfield CPU (where the bus frequency is equal to the Base Clock frequency) it makes more sense to talk about raising the Base Clock above 133MHz when overclocking Lynnfield than raising the QPI (as with LGA1366 CPUs, which do have an external QPI bus to link the CPU and X58 chipset).

The integrated PCI-E 2.0 controller of Lynnfield has 16 lanes on offer, which can be split in two to give two graphics cards eight lanes of bandwidth each. There are rumours that motherboard makers will be able to connect the Lynnfield PCI-E controller to Nvidia's NF200 chip to give extra PCI-E lanes and allow for 3-way SLI on a P55 motherboard. Similarly, there are shots of other PCI-E bridge chips, such as the Lucid Hydra chip.

However, while the NF200 chip will offer 32 PCI-E 2.0 lanes, we have it under (neutral) good authority that the latency cost of using the NF200 chip is not worth the bandwidth gain. Just like with the LGA1366 Core i7 and X58 platform, you'll not need the NF200 chip to get SLI either: this is offered out the box by pretty much everyone for a pre-paid $5 royalty to Nvidia, whether you want it or not. ATI's CrossFire is also supported by the PCI-E controller in Lynnfield.

Cache Latency

Apart from a few peripheral bolt-ons or downgrades, the basic design of a Lynnfield CPU is very similar to that of the Bloomfield-based LGA1366 Core i7 CPUs. It's therefore of little surprise that the cache latencies of the new design are identical.

P57?

At the time of writing there's no official word on Intel's Braidwood technology, which is meant to be an upgrade to the almost non-existent and decidely underwhelming Turbo Memory.

Turbo Memory was meant to add extra performance for commonly used programs in Windows Vista by providing a faster cache for Ready Boost. Braidwood modules connect via an additional socket on a premium P55 chipset called P57, and works by not only offering more space for the Ready Boost cache, but faster memory than the original Turbo Boost module offered.

Considering that SSDs are moving into the mainstream this year, and also that the Lynnfield system already costs nearly as much as a decent Core i7-920 PC, we doubt a premium Lynnfield chipset will ever see the light of day.