Saturday, October 1, 2011

Sandy Bridge-E VT-d Broken In C1 Stepping, Fixed In C2 Stepping,Shortly After Launch

Sandy Bridge-E
PC enthusiast customers and companies running corporate datacentres looking to buy into the new Sandy Bridge-E platform may want to wait a little while before handing over their hard-earned money to Intel. The initial batch of C1 revision Sandy Bridge-E processors have a bug – “errata” in Intel terminology – in them with VT-d, which means that hardware accelerated virtualization doesn’t work properly with them (software only mode is unaffected). The feature when working properly, allows all hardware acceleration to work on the hosted operating system (virtual machine). This would allow things such as hard drive controllers to work, plus applications such as high-powered 3D games, typically First Person Shooters, to run at nearly full speed and the full Windows Aero desktop to be displayed on the hosted OS, as the hardware features of the graphics card can be used. Therefore, working VT-d is a critical feature for these kinds of applications.

Sandy Bridge-E
Production of the C1 stepping should have already started, or is about to start. However, the C2 stepping isn’t expected until next year, as the qualification process isn’t expected to be complete until the end of this year.

Intel will only certify the Waimea Bay platform for PCI Express 2.0 at launch, since there aren’t enough third party cards to test with. Some PCI Express 3.0 devices are still likely to work, but Intel doesn’t guarantee compatibility. This doesn’t bode well for the current 6-series motherboard with gen 3 switches actually working properly once cards and especially, Ivy Bridge processors arrive. Waiting for full qualification before purchasing is therefore advised, or an expensive motherboard replacement may be required in the not too distant future.

There is some good news however. For those wanting to continue using Windows XP, the Waimea Bay platform will be compatible with both 32-bit and 64-bit versions of the operating system. However, Intel won’t be providing Rapid Storage drivers for 32-bit XP, which means that the basic Windows drivers will be handling drive access, which may not be optimal. Unsurprisingly, the upcoming Waimea Bay platform will also be supporting the upcoming Windows 8, when released.

It’s not so good on the chipset front, either. Intel has increased the price of the X79 chipset by 20% compared to the X58 chipset, putting the X79 chipset somewhere in the region of $70. This is the list price, so the discounted or “street” price should be a lot lower. However, we are looking at a chipset that offers no new features over X58 and it’s the same size as the 6-series chipsets – it should be cheaper to manufacture than the X58 chipset which only consists of the I/O Hub and the ICH10R. We wish AMD well with their new processors and chipsets, as competition can only be a good thing here and is clearly needed.

It's one thing for "errata" to be discovered some time after a product has been released and then to manufacture a revised processor, but it doesn’t seem right for Intel to release processors with a known major feature fault like this, especially as most buyers are unlikely to know about it and Intel is even less likely to shout about it. Therefore, buyers would be wise to wait for the bug-fixed C2 version before upgrading, unless they are absolutely sure they won’t need this virtualization feature. After all, are Intel going to offer a free replacement to the fixed version for customers of the initial C1 versions? Only this gesture can make releasing such an obviously flawed product right. Intel have offered such a free replacement recently with the faulty SATA controller, so there's hope yet they'll do the right thing. And just as importantly, it's worth keeping a close watch on what significant errata C2 might harbour, before upgrading.

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