The Raspberry Pi 2 Model B is more than six times more powerful than the prior version, the Model B+, according to the British charity behind it.
Previous versions of the kit have been widely adopted by schools and enthusiasts across the world.
But the Pi faces increased competition.
Another UK-based firm, Imagination, recently released a bare-bones computer of its own, and the Arduino, Intel Galileo, Gizmo 2, BeagleBone Black and Hummingboard also form part of a growing list of rivals.Imagination's Creator CI20 features built-in flash storage absent on the Raspberry Pi, but costs more Smoother video
The Raspberry Pi 2 makes two major changes to the previous version, while leaving other components unchanged:The CPU (central processing unit) is now quad-core rather than single-core. That means it can be programmed to use more of its cores to offer extra computing power, or made to use fewer to help save power consumption - useful if running as part of a battery-powered contraption. In addition, the Cortex A7 processor now runs at 800MHz rather than 700MHz The board now features one gigabyte of RAM (random access) memory, double the amount that was previously included
As before, owners will need to add their own keyboard, a MicroSD card containing a copy of the Linux operating system, and television/monitor-connecting cables in order to start programming. Enclosures bought for earlier models will also fit the new one.
"We think it's about six times more powerful for most applications," Eben Upton, founder of Raspberry Pi, told the BBC.
"This means this is really a PC now.
"You can do most of the things with this that you can do with a PC. You can surf the web, you can watch videos, you can play games like Minecraft. But we also bundle it with the tools that children need in order to learn how to program.
"The great thing is - apart from those two changes - that we've managed to keep everything else the same.The Raspberry Pi 2 is the same size as the prior version, so will fit in the same enclosures
"So, all of those tutorials that people have developed over the last few years will carry on working with this device. It just kind of broadens out the range of interesting stuff kids can do."
Existing software will need to be recompiled - meaning converted into a language the CPU understands - to take best advantage of the switch to the new multi-core processor.
The kit - most of which is manufactured at Sony's factory in Bridgend, South Wales - costs ?22.85/$35.
One industry watcher was optimistic it would repeat the success of its predecessors.
"It's success is guaranteed - there's a great user-base already out there, but more importantly the Raspberry Pi has a level of name recognition that nobody else has been able to match yet," said Chris Green, principal technology analyst at the Davies Murphy Group Europe consultancy.
"Its makers seem to have a really good handle on what makes these devices really popular, both for the hobbyists as well as people wanting to use them in education.
"The improvements also address what people had been wanting - for graphics-intensive tasks the extra memory will help a lot. It's also quite handy for media streaming, you'll get a smoother experience when playing high definition video, with less buffering."Beating the Spectrum
About 4.5 million units of the Raspberry Pi have now been sold, according to Mr Upton. But he added he didn't believe the market was close to being saturated.
"We're selling about 200,000 a month now," he said.
"The surprise to us is that people don't buy just one Raspberry Pi.
"There are a lot of people with five or six. And we think those people are naturally going to want this.
"We are very very close to it being the bestselling British computer. I think another half a million and we will go past the Sinclair Spectrum as the bestselling British computer."
The lower-specced Model A+, with just one - rather than four - USB socket, remains on sale costing about ?7 less.