The U.S. sales of video game hardware and software went up 47 percent compared to the same period last year, a report released by market research firm NPD Group unveiled. Overall, this accounted for yet another month with over $1 billion in sales in the U.S. alone ($1.23 billion to be more precise). And the star of April sales was of course Grand Theft Auto IV, which despite the end-of-the-month release, managed to total $500 million within its first week of availability.

From the hardware point of view, Grand Theft Auto IV didn’t change much after its release, although sales did go up 26 percent to $426.2 million. Nothing unusual in the overall standings, with the Wii keeping the lead position (714.200 units sold), although sales went down a bit, while Xbox 360 sold 188.000 units, compared to PS – 187.000 units.

Microsoft product management director Aaron Greenberg spoke with Gamasutra about the close figures between the Xbox and the PS3 this month, saying that this is usually a slower month of the year, from the hardware sales point of view, and that in the past, they’ve managed to outsell Sony almost every time (16 out of 18 months). He also expressed his optimism that May will be a better barometer for hardware sales.

NPD’s report for software sales found Grand Theft Auto IV on top of the chart, with sales of 2.85 million copies (Xbox and PS3 combined, with the Xbox outselling the PS3), while Mario Kart kept a strong second position, with 1.12 million copies sold.

With only five days of retail availability in April, there was a 63 percent split in sales versus PS3, Greenberg said about GTA IV sales on Xbox. He also explained a dilemma: if people buy consoles for games, why were the hardware sales so not impressive in April? According to Greenberg, people buy consoles mainly at holiday times, but Microsoft keeps extending the lead, despite launching a year before the PS3.