Hey there. I've been having this stuttering issue for quite a while now also. I don't notice it in music or any kind of sound based apps. In games (full screen 3D) the sound never stutters or misses a hitch, but the video does this thing where it's like - "smooth, skip, smooth, skip, smooth, skip" consistently. It skips at the same rate of time every time (once every half a second or so). This leads me to believe it isn't a performance issue (like fragmented HDD, low speed memory (or not enough), slow processor, slow video card etc.). My framerates are always excellent, but the problem seems to lie in possible frame skipping. I think it's some type of driver/hardware compatibility issue. I have tried XP SP2/SP3, Windows Vista 64, Windows 7 64, and I haven't noticed much of a difference. Some notable games that do this are Oblivion, Fallout 3, Blood (when running in Dosbox emulation), Daggerfall (when running with VDM Sound in XP), Doom 3, and Quake 4 to name a few. With all of these games there is a skipping that is always consistently on que time-wise. Meaning it always does it the whole time and on a strictly consistent basis. Seems like it could be an error in data flow, like I mean the data isn't flowing smoothly, it's skipping beats. I'm so frustrated.
My system - Pentium Dual Core E6300 @ 3.8 GHz, Corsair Dominator 1066 MHz (DDR2) 5-6-6-18 2T @ 2.1 v, ATI Radeon HD 4870 (Visiontek, 512 MB), Western Digital Caviar Black 640 GB with 32 MB cache, Antec 1200 case, DVD/RW/CD combo drive, Gigabyte EP45-UD3L Revision 1.0 board, X-Fi Xtreme Gamer sound card by Creative Labs, Antec EA-650 (650 watt) PSU, Zalman 9900 LED CPU cooler.