After a little reading, I find the specs hard to compare.
The Creative Titanium specs say it will output 1 Volt RMS which is not really what you measure output power in.... My little Fiio is only spec'd to 150mW, so I know what that means
Then again, the 150wW is at 32 ohms, and the 1W RMS is at 330ohms. I can't see the output impedance for the Creative, could be too high (should be low for lower impedance headphones), but this would make it incompatible with many generic headphones so I don't imagine that.
I think the best guess answer is you are pushing them harder (louder) than they were designed for. I'm still not convinced that its not something to do with your PC (how can I possibly ever rule this out), but as you have mentioned your levels are loud, it makes sense that you're asking the speakers to extend past their xmas (maximum excursion).
Wait... The Realtek 898 is a chip, not a card... what is the amplifier? what is the power rating (in Watts or milliwatts)
Quote: "We also have to clarify that although this card has a headphone output, this design does not have a headphones amplifier."
I think you need to find out if a properly amplified source is making your headphones max out or if you are underpowering them. By googing "sound blaster x-fi titanium hd headphone", the auto fill adds amp, so I think you are seeing that its designed to be paired with an amp.
I'm not an expert, I don't have many posts, but if you are not seeing mW specs on the soundcard, I don't know how we can tell you much...
Hope this helps, hope someone with real knowledge chimes in.
Edited by Noone025 - 2/12/13 at 6:03pm