Online retailers have marked OEM editions of Microsoft's Windows Vista with price tags close to those for Windows XP, backing up an analyst's prediction that the new operating system won't add to the cost of computers debuting with the software next week.

At such e-retailers as Newegg.com, the price of so-called OEM editions of Vista -- those sold to smaller-scale system builders as opposed to large computer makers like Dell or Hewlett-Packard -- are on average $10 more than comparable versions of Windows XP. The OEM price for Vista Home Basic, for example, is $100, while Windows XP Home costs $90. Vista Premium ($120) and Vista Business ($150) also compare closely with their XP cousins, Windows XP Media Center Edition 2005 ($110) and Windows XP Professional ($140). OEM it stands for original equipment manufacturer.

"No, Vista won't add to the price of PCs," says George Shiffler, a research director at Gartner who tracks PC prices and sales numbers. "Prices will, in fact, fall, but that's forged by larger forces in the market, such as saturation and an attempt to expand the market, not Vista."

One of the exceptions to that rule will likely be computers with Vista Ultimate preinstalled; there is no Windows XP comparable for Ultimate, which sells in an OEM edition at Newegg.com for $200, 33% more than the next-lower-priced version, Vista Business.

PC makers, who will put Vista systems on sale in retail and online starting Jan. 30, have not disclosed pricing for those machines.