Qubehead
I think the assumption can be that there's so much horsepower in today's machines that latency shouldn't be an issue for uses that aren't graphically intensive but one never knows.
Latency can indeed be a major issue when dealing with low-latency audio recording and production work on even the most powerful PCs if they aren't optimally configured for what is a very specialised job.
The audio driver has a 'buffer' which is essentially how much audio it stores ahead of the current play time. If that buffer at any point is empty then you get glitching at best and dropouts, where the DAW audio engine stops, at worst. The problem essentially is that Windows is not a real-time operating system but a multi-tasking operating system that relies on serving the demands of various drivers and applications all competing for its attention. So if e.g. a device driver grabs Windows attention for a period longer than the audio buffer then it's dropout time.
The root cause of this is Windows method of making PCI bus/delayed procedure calls to the hardware and how long the hardware and driver takes to respond. Wireless network cards, for example, frequently cause issues because for whatever reason they can grab Windows attention for an extended period, though again it's only milliseconds this can be enough to stall a DAW unless the audio driver buffer is large enough to cover them. But a large enough buffer can result in too much latency....
There's a useful free application called latencymon which can report on how much of a problem PCI/dpc latency is and what might be the cause of it.
Most of the time Windows for all intents and purposes runs OK for 'normal' applications. If Word or even a game pauses for say 20 milliseconds while Windows does something else the user won't notice the 'hiccup', it's that short. A DAW such as Sonar (or any other DAW) would notice it though if the audio driver buffer is set to under 20ms. Which may not sound much but the resulting lag is very obvious to most musicians.
The 'usual' Windows audio drivers have a pretty huge buffer, far too large for serious audio recording and playing software instruments though perfectly fine for media and video players. Which is why the preferred driver model for Windows DAWs is a purpose-made interface with an ASIO driver supplied by the interface manufacturer. Sonar Platinum can also use WASAPI drivers in a way that can often give low latency with the on-board sound chips present on motherboards, but that's very recent. ASIO drivers can give low latency, though they aren't all born equal any more than audio interfaces are.
ASIO4ALL is a driver which kind of emulates what an ASIO driver does and is claimed to work with pretty much any on-board sound chip. People have varying rates of success with it, it can be tricky to set up and reports indicate it sometimes causes problems if not uninstalled before a 'real' ASIO driver is installed. It might be worth a try if all you need is low-latency playback/software synths.
Most DAWs and audio processing place little if any strain on the graphics system by the way. Intel's on-chip graphics are perfectly up to the job. Which is actually quite useful if, like many DAW users, you want to make a computer as acoustically quiet as possible - no need for noisy gpu fans. In fact a powerful Windows DAW tends to look much like a powerful gaming PC except without the emphasis on graphics performance and with (hopefully) far fewer fans.