Lagarith Lossless Codes - weird problems with new AMD drivers

hey guys, I recently got an R9 290 and all of a sudden, today .avi were totally laggy in Media Player Classic and VirtualDub.
The videos are like in slow motion and keep skipping ahead by 1s every 2s.
The audio keeps dropping every 3 seconds.

.mp4 files played just fine. The .avi files play just fine with VLC.

After trying various things I found out that uninstalling Lagarith Lossless Codecs removes the problem for clips that, ironically, are coded with LAGS. For other .avi files with other codecs the problem persists.

I am at a loss, I have no idea what is causing it and how I can fix this. I suspect it has something to do with the AMD drivers, since I never had a single issue with codecs with my GTX670.

Any idea what the issue could be?
Any help much appreciated  

1) Uninstall the driver.
2) Go to Windows Control Panel > System > Device Manager, and remove your graphics card
3) Reboot
4) Windows will re-detect the card
5) Install latest driver

WOW....that actually sort of worked
thank you so much!  

I also removed MPC and ran Driver Sweeper when uninstalling.
I then installed K-Lite standard pack and the included MPC.
Suddenly it all works like before except for 60fps videos, they keep stuttering.

Also, what was the issue before I reinstalled the drivers, because when I installed them the first time I did a clean install too (removed old drivers with driver sweeper etc).
The issue suddenly appeared 2 days later....

EDIT:
For some videos which had been "cut" by Virtual Dub I was able to fix the 60fps issue by enabling VC1 and H264 in the options under Internal Filters.

It is hard to say why your previous attempt did not work. Maybe explicitly removing the device helped. Perhaps some stuff from the old card was left behind.

Enabling those internal filters should normally not be needed. By default it should use decoders that are the same as the internal ones (LAV Video). You may have some other stuff installed that was interfering (due to higher merits). The latest update for the pack (10.1.9) may help improve that situation, as the merit of LAV Video decoder was increased.

yeah perhaps removing the device did the trick.

I am still getting issues though, what I noted is that the videos I recorded with Mirillis after I installed my R290 do have a playback issue still, the ones I recorded when I had a GTX670 replay fine.
I'm baffled.

Should I uninstall UT Codec Suite?

Can you record a short sample and upload it somewhere for me? Then I can test if it plays smoothly here. Maybe something is wrong with the files.

sorry I have to revise my statement, I can't exactly say when it happens and when not. Sometimes it happens on a particular video and next time it doesn't. I need to check more videos to establish a pattern, it's definitely not the files, they play 100% fine in Sony Vegas.

What I have noticed though is that when I play a file and jump ahead using right arrow, that's when the stuttering kicks in. Sometimes it recovers, on occasions it doesn't.

Does it only happen with those (lossless) recordings? You could try disabling the relevant formats in LAV Video decoder. Then the installed VFW codecs will get used by MPC-HC.

Defragmenting your harddrive may help in case the stuttering files are highly fragmented.

Yes, .mp4 is totally fine.

I downloaded and installed the WMV9VCM codec and after I made a few more organised tests with the following results

LAGs cut with Virtual Dub 30fps - plays ok, skipping cause fps drop of 3fps for 1 second
LAGS uncut 30fps - plays ok, skipping cause fps drop of 3fps for 1 second
FICV cut with Virtual Dub 30fps - plays ok, skipping causes fps drops of 6fps for 5 seconds
FICV uncut 30fps - plays ok, skipping causes fps drops of 6fps for 5 seconds
FICV cut with Virtual Dub 60fps - supper laggy, skips 1s every 2s, tries to play it at 30fps
FICV uncut with Virtual Dub 60fps - supper laggy, skips 1s every 2s, tries to play it at 30fps

So it has gotten better, however when skipping ahead by 5s in FICV videos it goes into full derp mode for 5s
And 60fps still are a problem.

Where is the LAV video decoder? Also, how do I know I have the VFW codecs installed? Sorry I am total noob at codecs

The Codec Tweak Tool can generate a log with all installed codecs.
All the codecs that VirtualDub uses are VFW. For example the Lagarith and UTVideo codecs you used, and also WMV9VCM, Xvid, and x264VFW.

You can access the settings of LAV Video through the shortcuts that the codec pack makes in your Start menu.

An interesting test you could do:
In MPC-HC options > Playback > Output > select NULL video renderer
The effect will be that the decoded video is not displayed. Check if the same lag occurs when seeking. If so, the problem could be due to a slow harddrive and/or fragmented files. Lossless video files are much larger than regular videos, so more data needs to be read. Seeking causes buffers to be emptied, which must be refilled.

Hey, thanks for the support so far, I will check these things for you after the holidays, so in New Year, but right now it's all kinda working, especially the 60fps videos that I recorded with the new graphics card work fine ok.
However now Sony Vegas keeps crashing right at the end of the rendering process, presumably when it applies the header to the file, and it's pointing to some mcp.....plug-in. So I don't know what's up with that, you wouldn't know why by chance?

That seems to be one of the internal codecs from Vegas (mc = MainConcept). I can't help you with that.