Microsoft has declined to comment directly on rumours that it has updated the 360 with a second GPU heatsink - but has said that such upgrades are "commonplace within the industry".
The comments come after some European Xbox 360 owners reported that consoles they sent away for repair were returned with an extra heatsink installed.
There have been suggestions in the past that the 360 suffers from overheating problems, and there is now speculation that the addition of a second heatsink is an attempt to solve the problem.
Speaking to GamesIndustry.biz a Microsoft spokesperson explained: "Regularly updating console components is commonplace within the industry and is a standard aspect of the business for a variety of reasons including cost reduction, improved manufacturability and improved performance."
However, the spokesperson declined to specifically confirm or deny the second heatsink rumours, adding, "We do not provide details on these updates."
It is not known whether Microsoft may make this a permanent design change in all future console manufacturing, or if repairs done in the US will include a similar addition.