Intel in January stopped shipments of the Series 6 chipsets used with its much vaunted Sandy Bridge processors. The reason: a problem with the SATA controller that could over a period of time cause problems with SATA-linked devices.  PC Advisor explains what Intel's design flaw means for those who are about to buy an Intel Sandy Bridge PC, or have already taken the plunge. Updated, 16 February 2011.

Intel halted shipments of a key chipset used with the latest-generation Core i5/i7-series quad-core processors in late January.

The Series 6 chipsets are used with Sandy Bridge CPUs. The reason: a fault with the SATA controller that could cause long-term problems with SATA-linked devices such as hard disks and optical drives.

Specifically, the PC's motherboard that manufacturers such as Asus, Gigabyte and MSI have been providing to PC makers could suffer failure after prolonged use.

Intel has stopped shipment of the affected support chip, the platform controller hub (PCH), codenamed Cougar Point. The design issue has been fixed, Intel has said. But what exactly happened, and what can you expect if you've bought or are planning to buy a laptop or a desktop PC with a Sandy Bridge processor?

See also: Sandy Bridge mistake shows just how important Intel is

See also: Intel Core i7-2600K (Sandy Bridge) review

Intel Sandy Bridge: The problem

The Cougar Point chipset allows up to four SATA ports at the legacy 3 gigabits per second (Gbps) speed, and two with the higher-speed 6Gbps interface. The problem lies in the SATA 3Gbps interface.

Note: there is some confusion over the naming of different generations of SATA interface. At PC Advisor, we use the unambiguous convention based on communication rate speed: first generation of the SATA interface was specified at 1.5Gbps, and is sometimes called ‘SATA 1'. This was followed by SATA 3Gbps, or ‘SATA 2'. SATA 3 is really SATA 6Gbps.

According to industry sources, the interface that controls the movement of data – also known as the ‘clocking tree' – has been fitted with a transistor whose voltage was biased too high, resulting in a high level of leakage current. Leaking current could, in time, cause the SATA 3Gbps ports to fail. Intel maintains that this would not cause any damage or corruption to a connected hard disk, for instance, but we have heard predictions that 5 to 15 percent of systems could break down within three years.

It's a microscopic and massive error, but one that's relatively simple to fix in new products. So what about those products that have already shipped?

See also: Latest Components/Upgrades reviews

Intel Sandy Bridge: What happens now?

Many industry insiders expected that Intel would recall all the chipsets, and those people who already had Intel Sandy Bridge PCs would have to return them for repair.

As big a problem as that would be, the relatively few people who already have such laptops and desktop PCs pales into insignificance next to the real issue: the millions of motherboards already shipped or in transit to PC manufacturers.

One option open to PC suppliers is to supplement the sale of a new PC with a lengthy ‘no quibble' guarantee – possibly with financial support from Intel.

But PC makers are beholden to motherboard suppliers. Gigabyte, for instance, issued a Q&A unveiling its plans for the affected motherboards. In part it says: "No action will be needed if you use only the SATA 3 [sic] ports. If you are using the SATA 2 ports, then there are possibilities that the device's performance will decrease after a period of usage.

"To ensure the highest standard of customer support & services, Gigabyte recommends that all customers who purchased Gigabyte 6-series motherboards contact their local dealer (retail store where you purchased the motherboard) at the end of April for a motherboard exchange. Gigabyte will provide an equivalent new motherboard replacement."

Or to put it another way: the consumer needs to work out if they have an affected PC – and that means ascertaining whether they're using all the PC's capabilities, and whether they ever intend to – then take the motherboard back to the PC vendor to be swapped for a new one.

On the face of it this seems to be a disingenuous offer – as one PC Advisor staffer quipped: "It's not exactly like just pulling the tray out of the toaster to empty the crumbs out." A motherboard replacement is a delicate procedure that we wouldn't recommend to most users.

Asus, on the other hand, told PC Advisor that it intends to offer full refunds to any consumer who has purchased a PC with a faulty board it supplied. It said that it was calling a halt to all sales of potentially affected motherboards, and that customers should contact their PC vendor.

See also: Find out your consumer rights

Intel Sandy Bridge: Should you buy now?

Tests we've carried out in the PC Advisor Test Centre have established that Sandy Bridge is a considerable step forward in performance. However, with supplies of remedied motherboards in short supply until April, it may be time for pause for thought if you're considering buying a PC.

In a statement released 31 January, Intel said the "total cost to repair and replace affected materials and systems in the market is estimated to be $700m. Since this issue affected some of the chipset units shipped and produced in the fourth quarter of 2010, the company will take a charge against the cost of goods sold".

But this isn't clear enough in explaining to the end user who will fix their PC if it should break down due to a faulty chipset. We asked a selection of UK PC makers what their intentions are on this issue.

NEXT PAGE: what the UK PC makers say >>