Just thought I'd share this whilst it's still fresh in my mind as anyone who has had to mess around with getting decent PC DVD playback knows it's a real PIA. My HTPC system is NOT overclocked at all: Pentium4 2.8b 512MB Ram Geforce4 Ti4400 128MB Triple Boot Win XP Pro SP1, W2K Pro SP4, W98SE with all the latest drivers/fixes. DX9.0b & 52.16 Detonators on all 3 O/S's. Creative SBLive Value (circa 1998) latest Creative Liveware drivers/fixes. Pioneer DVD106 always set to R1. What I am about to talk about only applies to my R1 playback on a CRT Computer Monitor @ 1024x768x32@85Hz. I have not tried outputting the signal to an external source like a TV or Projector. For ages under Win2000 I have been struggling to get smooth playback without any stuttering/judder on either audio or video or both depending on the movie even though I used to have flawless playback a summer HD crash meant a rebuild and it has never worked the same since. My findings are: 1: Win98SE playback with NVDVD & PowerDVD4 XP Deluxe (build 2417 patch not required) is flawless with no stutter that I can detect. WinDVD5 & PowerDVD5 however have terrible stutter. Neither gives the same result on the same movie as problems happen in different scenes sometimes audio sometimes frame drops on pan shots so forgot those 2 newer players for W98SE. 2: Win2000 Pro SP4 playback with WinDVD5 suffers with sync issues as does PowerDVD5. NVDVD does not even run under W2K even with the Nvidia patches applied. Re-Clock does not make any difference here either. Best W2K player for me anyway is PowerDVD4 XP Deluxe with the Build 2417 patch applied otherwise it does not work. 3: Windows XP SP1 playback with PowerDVD5 has dreadful sync issues and is unstable on my system. Not even Re-Clock can help out here as it just introduces different stuttering issues. WinDVD5 is better (you have to play aroundwith the Bob, Weave, Progressive settings on a per movie basis) but again depending on the movie minor audio/video sync issues which Re-Clock cannot totally compensate for on a CRT monitor. NVDVD does not work on XP even with Nvidia's patches. PowerDVD4 XP Deluxe (needs the build 2417 patch applied to run under XP)performs smoothly with no sync/stuttering issues I can detect. Re-Clock does not activate when PowerDVD4 XP Deluxe is running so I assume it must use an older DX overlay. My conclusions are: 1: PowerDVD4 XP Deluxe with build 2417 patch applied is the best software DVD player for smooth stutter free R1 playback on a PC with CRT Monitor regardless of your O/S. 2: NVDVD is the best choice if you only have W98SE and a recent Nvidia GFX card GF4 or higher. 3: PowerDVD5 & WinDVD5 may have some newer features & fancy settings like placing the DVD playback in the desktop but lack basic stutter free playback so consider public beta's & avoid until they fix the problems. 4: Microsoft must have changed the way DVD playback is handled somewhere in between W98SE & XP/2K. It could be a function of DirectX seizing more control under these newer O/S's but whatever it is needs to be fixed as it's nonsense that an older O/S built on an early 1990's legacy core can handle something the newer O/S's cannot. 5: DXVA makes no difference on my system to DVD playback performance. The refresh rate I'm using is not even an exact multiple of the NTSC standard so as I have not been able to detect any sync/stuttering issues can only assume that it must be so slight as to not be noticeable or requires a longer movie to show up (I did all my testing on movies in the 1.5-2.5 hour range). Failing that perhaps the GFX card locks onto the signal differently for older video overlays or my Pentium4 is so fast it eliminates the stutter before I can notice it.