Intel doesn’t like talking technology before it is ready. That is one of the enduring truths of the PC industry. A new processor launch involves a careful managing of information, getting it into the hands of those who need it to build products like motherboards, while keeping it out of the hands of the general public (and us journalists who act as a conduit to the general public).
So when a battle breaks out between motherboard manufacturers there is often a huge, missing piece of the puzzle... An Intel shaped piece, carved from stoicism and emblazoned with no-comment. Such is the case at the moment – ASRock and MSI are doing their damnedest to make PCI-Express 3 support a selling point for their motherboards, even though processor support won’t happen until Intel’s Ivy Bridge processor hit the market next year.
At a base level both ASRock and MSI have announced support for PCI-Express 3 in new motherboards. While not much is known about Ivy Bridge, we do know that it will be compatible with existing Socket 1155 motherboards. You should be able to pick up a Z68 based motherboard today and when the new CPUs launch all you’ll need to do is update your BIOS, drop in the chip and it should work.
MSI is using the suffix (G3) to let consumers know that the motherboard supports PCI-E 3.
Historically this would have limited you to whatever version of PCI-Express shipped with the motherboard. But Intel’s current CPU architecture incorporates a controller for the graphics lanes, effectively cutting the motherboard out of PCI-Express 3 control. At the other end of the PCI-Express pipeline you’ll need something that can talk to the CPU in PCI-Express 3, which means an as-yet unannounced next generation graphics card.
We don’t even have an indication of when these PCI-Express 3 graphics cards will launch, which in and of itself renders a lot of the PCI-E 3 discussion moot. If you physically cannot get your hands on the two ends of the PCI-E 3 pipeline, then support is the last thing you’ll care about.
With all of this in mind the last thing we’d advise people to do is buy a motherboard based around PCI-Express 3 support. In order to get anything out of it you’ll need to upgrade both CPU and graphics card sometime next year (assuming graphics cards even appear then), while keeping a motherboard bought this year. Not only is that a nonsensical upgrade path, odds are that we’ll be years away from a situation where a graphics card will actually NEED a x16 PCI-Express 3 connection.
Why we are being made to care
The marketing campaign around PCI Express 3 is already nasty, and hit a new level when ASRock unveiled its latest print ad on its facebook page. Depicting a sledgehammer smashing a Gigabyte P67A-UD7, it has had quite an impact. We were in a briefing with Gigabyte when the news arrived, and they aren’t too happy at the direction the marketing campaigns are taking.
This ad is the latest blow in the marketing battle - despite the fact that the motherboard being smashed doesnt even tout PCI-E 3 support.
What we have been able to find out is as follows. As is usually the case with a new CPU architecture, even a process shrink like Ivy Bridge, you will have to upgrade your motherboard’s BIOS to add support. A side effect of this is that it will enable PCI-Express 3 on your motherboard. Once you plug in a PCI-Express 3 graphics card the two will communicate via PCI-Express 3 without problems.
In other words the wires currently inside your Intel 6-series chipset motherboard are capable of a PCI-Express 3 connection. Theoretically if you have a single PCI-E graphics card slot on your board, this will mean that you have the full 16 lanes of PCI-Express 3.
As always theory and practice are different, and that’s where the current marketing battle is taking place. Most motherboards have multiple graphics slots, designed to support Nvidia’s SLI and AMD’s Crossfire multi-GPU technology. In such cases the PCI-Express lanes coming out of the CPU get split, usually running eight lanes to the first graphics slot, and then another eight lanes into a switch. This switch then controls whether the motherboard runs with a single x16 slot (in which case it routes the lanes back to pair up with the eight coming from the CPU) or as dual eight lane slots (in which case it routes the lanes to the second PCI-E graphics slot).
These switches are the weak link in the chain. They need to support PCI-Express 3.0 in order to be able to switch a PCI-Express 3.0 signal. Most current motherboards only feature PCI-E 2.0 switches, so when an Ivy Bridge CPU is plugged in only eight lanes will work at the new speed.
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