Microsoft Corp. has acknowledged and patched a glitch with its Windows XP Service Pack 1 (SP1) update that can cause system slowdowns, but has not yet made its still-developing fix widely available.

Because of changes made in SP1 to Windows XP’s memory management system, programs that affect large blocks of memory may take up to ten times longer to load on a system running SP1 than on one without, Microsoft said.

The bug affects both the Professional and Home Edition versions of Windows XP. SP1, released in September, includes fixes for a number of security flaws and bugs discovered since Windows XP’s release.

For now, the only official way to obtain Microsoft’s fix is to contact the company’s Product Support Services department. Unless users are severely affected by the problem, Microsoft recommends waiting for a patch until the next Windows XP service pack is released.