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Unofficial VirtualDub Support Forums > Testing / Bug Reports > Amd 2400+nforce2+integer Sse Problem

Posted by: martinr Aug 6 2003, 05:33 PM

Unfortunately the forum search rejects both "AMD" and "SSE" as keywords ...

There seems to be a problem with the SSE-Integer CPU feature with my AMD XP2400+ on an nforce2 mobo under Windows 2000 (sp2/3/4).

Whenever I quickly move about a Mediafile loaded into VirtualDub holding down Cursor-Right or -Cursor-right then the frame output almost freezes in a simultaneously running Mediaplayer-Movie or the TV-card display and/or capture with WinDVR. I also get significant and noticable framedrops in those apps when I have VirtualDub frameserving to TMPGEnc in the background, and even when I set VirtualDub to Low Priority and MediaPlayer or WinDVR to High or even Realtime priority.

However as soon as I switch off "Integer SSE" in Options/Preferences/CPU this strange interference with the task-switching disappears.

For almost 6 months I had my digital VCR running with a Elitegroup K7S5A mobo (SiS-735 chipset) an AMD 1800+ and cheap PC-133 SDRAM and it never showed such strange behaviour.

But with the new nforce2 Mobo (MSI K7N2-Delta-L), PC-266-CL2 DDR-RAM and AMD 2400+ CPU it plain doesn't work right with "Integer SSE" enabled, although I get about 30% better framerates when transcoding captured material.

I tried everything I could think of (fresh OS install, fresh install with ACPI turned off, manual IRQ assignments, P2/3/4, Nforce-drivers 2.03,2.41,2.45) but absolutely no change in behaviour.

What exactly does the "Integer SSE" optimization in VirtualDub do?

Posted by: fccHandler Aug 6 2003, 06:24 PM

Let me get this straight... You're encoding with VirtualDub + TMPGEnc, and watching a movie in Media Player, and capturing video with WinDVR, all at the same time, and you're complaining about dropped frames???

In answer to your question, the "Integer SSE" option lets VirtualDub use Intel's Streaming SIMD Extensions (which should boost its performance), but I doubt that this is the root of your problem. I don't have an AMD, but I'm pretty sure they support the ISSE instruction set.

Each of the tasks you've mentioned is tremendously CPU intensive, so the behavior you describe is almost to be expected. I think you just need to lighten the load on your CPU, especially when capturing.

Posted by: martinr Aug 6 2003, 06:53 PM

QUOTE (fccHandler @ Aug 6 2003, 12:24 PM)

Each of the tasks you've mentioned is tremendously CPU intensive, so the behavior you describe is almost to be expected. I think you just need to lighten the load on your CPU, especially when capturing.

Maybe I wasn't clear enough.

- there is a serious task-switching problem in W2K with my nforce2 mobo w/ AMD 2400+ and it *TOTALLY* goes away if I manually switch off "Integer SSE" in VirtualDub -- the load of the machine is definitely *NOT* a problem

- this problem didn't exist on a much less powerful setup with SiS-735/AMD 1800+ and PC133-SDRam

- The problem shows even with something simple as playing a 352x288 MPEG1-VCD in MediaPlayer in the background and quickly advancing in a Movie-file in VirtualDub by holding down Cursor-right or Alt-Cursor-right. The Movieplayer will only render 1-5 Frames per second instead of 25. Similar behaviour if I'm running WinDVR to look TV via TV-card (video overlay) instead of having Mediaplayer playing a VCD.

This is either a problem of the AMD 2400+ CPU (but I doubt this, I didn't notice anything while I had this CPU running in the SiS-735 board for a week before I got the Nforce2 board), or (and that is my assumption) it is a problem of the MSI mobo, the NForce2 chipset or the
NVidia chipset drivers.

I have the most recent NVidia chipset drivers 2.45 installed. (The Audio-Driver from any of the 2.4x release is required, or TV-capture will exhibit audio dropouts, even on an otherwise idle machine).

Posted by: fccHandler Aug 6 2003, 08:30 PM

Sorry, in that case I don't know what it could be. Hopefully someone more qualified will jump in with some insights. Good luck.