Countering recent claims by Microsoft, the game sales performance gap between Sony's PlayStation 3 the Xbox 360 isn't as big as many think, Sony is claiming.

Ahead of an upcoming interview with Sony's Peter Dille, the company has detailed to Gamasutra a series of examples from major blockbusters, from Street Fighter IV to Grand Theft Auto IV.

The statistics are intended to suggest that not only are unit sales fairly similar on both platforms -- but that the PlayStation 3 actually has a higher per-title attach rate.

"If you factor in Xbox 360’s longer time in the marketplace and larger install base, Xbox 360 should be selling twice as many software units as PS3 if attach rates were equal -- and that is just not what we are seeing at retail with many multiplatform titles," the company tells Gamasutra.

Sony Vs. Microsoft: Attach Rate Comparisons

According to Sony, as of the beginning of March 2009, the Xbox 360 SKU of Street Fighter IV has only outsold the PS3 version by about 44,000 units thus far -- "that's closer to a 1:1 ratio than a 2:1 ratio," Sony says.

In fact, Sony says its U.S. attach rate for Capcom's blockbuster sequel is better overall: with 402,919 software units sold life to date on the PS3, its attach rate is 5.5 percent, whereas with 446,435 units, the Xbox 360's rate would be only 3.1 percent.

The picture looks even better for PlayStation 3 with Tomb Raider: Underworld, which actually sold more units thus far in the U.S. (136,245) on PS3 than Xbox 360 (108,784) -- spelling an attach rate of 1.9 versus .7 percent, respectively.

The gap wasn't too wide with Ubisoft's Prince of Persia, either, where only 36,000 units separated the Xbox 360 and PS3 in America. The game sold 304,851 units on the Xbox 360 (2.1 percent attach rate) and 268,935 units on the PS3 (3.7 percent).

As for Grand Theft Auto IV, Sony cited the franchise's "rich legacy with the PlayStation brand" to explain its 26.9 percent attach rate versus Xbox 360's 23 percent. However, the Xbox 360 version has still sold 3,362,196 units to date in the U.S., compared to 1,959,798 units for PlayStation 3, according to stats provided to Gamasutra by Sony.

Sony, Microsoft, And Metacritic

Xbox 360 product management director Aaron Greenberg recently talked to Gamasutra about the critical success of the platform's titles: "We have over 130 titles rated over 80 on Metacritic; no other platform even has 100 at that level," he said, following February's NPD results.

But now Sony cites Metacritic data from April 2009's top 10 games on each platform to suggest that at 31 percent, it has a higher percentage of titles scored 80 and up than the Xbox 360, which has 23 percent.

"This means one out of every three PS3 games have an 80+ score, while Xbox 360 has one out of five titles that have garnered 80 + scores," says the company.

Sony also points to Metacritic scores to suggest that the Xbox 360's ratings heyday might be behind it. "Of the top 10 scoring PS3 games on Metacritic, 7 were released in 2008 or 2009."

"On the other hand, most of Xbox 360’s top rated software titles were released back in 2006 and 2007, when the console had little to no competition, with Xbox 360 only releasing 4 of its top 10 rated in 2008 or 2009," says Sony.

Finally, the company also says the top PlayStation 3 titles on Metacritic are younger than the top Xbox 360 titles: "The average age of PS3’s top 10 games on Metacritic is 9.3 months. Compare that with the average age of Xbox 360’s top ten, which averages around 15.7 months."

These numbers provide some interesting counterarguments to recent Microsoft claims, and Gamasutra will be publishing its Peter Dille interview -- providing further background on the stats -- in the near future.