I'm planning on building a build in the up-coming months and will be geting this which supports PCI-E 3.0, now will an i5 2500k be able to run PCI-E 3.0 and the full speed or should I wait for Ivy Bridges?
PCIe is integrated into the processor. The current chips of the 2xxx series only support PCIe2. You will either need a Sandy Bridge-E series processor (which is crazy expensive), or wait for the Ivy Bridge processors which will be released late Q1 or early Q2 of 2012.
There are motherboards which will 'support' PCIe3, but as the PCIe lanes are on the processor it just means that they will later take an Ivy bridge processor, and allow the PCIe3 bus to pass through. How true the advertizements are on PCIe3 support is cannot be tested until next year.
Besides, there are no PCIe3 GPUs out yet, so if you are building now, you will need to buy a processor next year, as well as a PCIe3 GPU next year. Not to mention there will likely be better chipsets out next year with the new processor release, so if PCIe3 is of major concern for you, then just wait till next year
I strongly suggest you wait a few months for PCIe v3 to sort itself out. I have heard that many of the motherboards are NOT compatible with any existing CPUs.
It is actually possible to integrate the PCIe controller into the controller OR the motherboard. I know because I am using the i7-860 CPU with integrated controller but I got the motherboard with the NF200 chipset from NVidia which takes over (sort of, it is complicated.)
I am not sure if it has been confirmed whether there will be motherboard support but I have a feeling it will be only available in the CPU.
- PCIe v3 controller is in the CPU (I believe)
- no current CPUs exist on the market that support this motheboard
Keep in mind that if you are building a computer now you could still run a mainstream PCIe3 card in a PCIe2 slot. It is just the upper end cards (specifically those with 2 GPUs on 1 board) which will be choked for bandwidth. But if you are not hurting for an upgrade, then wait a little bit until all the new standards get sorted out and become more pervasive in the new systems (PCIe3, USB3, SATA3, thunderbolt/lightpeak, and WiDi just to name a few). But if you need to upgrade now like I just did, you won't be disappointed.