AviSynth 2.51 slower?

Great work Sh0dan although I'm experiencing some speed problems with the new build... but maybe it's just my fault AVS Script: LoadPlugin("c:\dvd\MPEG2Dec3.dll") MPEG2Source("f:\dvd\FaA\1.d2v",cpu=4) Crop(4,4,710,568) lanczosResize(640,352) XviD Settings: Motion Search Precision 6 VHQ Mode 4 B-Frames 2-150-100-0 Chroma Motion And Quarterpel enabled Chroma Optimizer enabled System Config: Asus A7N8X Athlon XP 2700+ Speed: 9fps! I'm using AviSynth Build 2.51, the latest MPEG2Dec3 and Koepi's XviD-08032003-1 build. Before I installed the new AviSynth version I reached around 13fps with the same source... Has anyone experienced a similar impact on encoding speed with the new AVS version?? If there's anyone out there who has a similar system and is using the same settings like me, how many fps do you get?

2.51 should be faster. Are you using the exact same encoding environment? (ie. same XviD build, same source, same script, etc.)

Everything should still be the same, VDubMod version, XviD build, XviD settings and the script that was used. The only thing I did that day was download the newest versions of some filters including MPEG2Dec3. Although I thought I would have already been using v1.0, the file I replaced had a different size... As you can see I'm using none of these filters (and am really scared of using c3d), although I'm loading them in the script which shouldn't make a difference. Maybe there's some old avs versions floating around on my system, I'll try to completely remove them and will reinstall the new one... (could this be a problem?) Anyway 9fps is really slow for my config, isn't it? I must have changed something, right? I'm sure there was a speed decrease since I'm constantly encoding movies without changing any of my settings.

Thanx for the advice, sh0dan. I'll try it out and report back to you tomorrow... BTW I just reinstalled the old version and could not see a difference in speed... So the problem doesn't seem to be related to the AVS version.

@sh0dan I made a couple of tests with different sources and different XviD configurations setting encoding mode to "Null - Test Speed". After a while I could convince myself that the speed is totally fine, even higher than with the old AVS version I was using. I still can't find a reason why I used to get 13 fps before, even with QPel turned on and VHQ set to 4, but when I saw those 5 hours of estimated time and those awfully slow 8 - 9 fps I must have panicced. This means, I might have started this thread a little to soon, I should have made some more benchmarks... I'm terribly sorry if I made you worry in any way.

@crOOk for the answer to why it is slow; However, I am not experiencing the slow down as some of the users are having. Please pay attention to posts from @theXung and @syskin for the answer that you are looking for.