HP, one of the world’s largest maker of digital equipment and personal computers, said it might have to repair or recall up to 900 thousand of notebook computers as a result of a flaw found in third-party memory modules used in the company’s mobile PCs.

During what HP calls routine testing of HP- and Compaq-branded notebook PCs, the company identified a design flaw in certain notebook memory modules used across the industry that could potentially cause users to experience serious problems with their notebooks. The memory modules in question are not manufactured by HP and were supplied by third parties.

Memory chips used on memory modules were made by Infineon Technology, Micron Technology, Samsung Electronics and Winbond, an HP spokesman said. The flawed memory modules could potentially result in blue screens, intermittent lock-ups or memory corruption. The same models might potentially be used in notebooks from other vendors as well.

Palo Alto, California-based HP said problems can arise when the chips, or memory modules, are used in conjunction with chipsets made by Intel, a separate video graphics controller and Intel’s Pentium 4 for mobile PCs or the Pentium M processor and a type of power management technology, according to a Reuters report citing HP’s officials.

To protect customers, HP is instituting a voluntary replacement program for those who have purchased Compaq or HP notebook PCs with the affected memory modules – at no cost to the customer.

“We are taking immediate steps to notify customers, partners and our employees to rectify the situation as quickly as possible. While the probability of occurrence of this issue with the memory modules is low and dependent on the user’s environment, we think it is important to notify our customers of this potential problem,” said Ronald Kasik, director, Total Customer Experience Customer Engineering and Marketing, Personal Systems Group, HP.

The affected notebooks include several models in the Compaq Evo and Presario lines, as well as the HP Compaq Business Notebook nx7000 and HP Pavilion zt3000, according to a report at The Street.