If you take a screen shot with and without the crispy textures, do you see a difference in the still images? Perhaps you could post a before and after image, which would help to figure out what the issue is.

Do you just have an extremely high frame-rate and it's just plain old screen tearing?

Reenabling vsync still shows the problem, so I doubt it has to do with that.

I'd imagine it's some reinitialization oversight (if it's reinitializing the video hardware), otherwise I have no idea.

Thanks for all pointers and replies.

I did some more testing and made some screenshots/ still images:

1. With v-sync

2. Without v-sync

3. Without v-sync at start (no switching)

It appears that results 1 and 3 are the same, so that probably means it doesn't have anything to do with V-sync.

Maybe something with the resetting of the device.

Below are the 3 screenshots and my reset code, what would you think?

With V-sync:

Without V-sync:

And without V-sync, at start (no switching):

Some code:

/**************************************************************************************/
/***									SET VSYNC									***/
/*** ==> usage: enables or desable vsync for d3d rendering							***/
/*** ==> updates the vsync bool in the d3d settings struct and resets the device	***/
/**************************************************************************************/

bool CD3d::SetVsync(const bool pVsync)
{
	if(mSettings.GetVsync() == pVsync) return false;
	
	mSettings.SetVsync(pVsync);
	if(mSettings.GetVsync()) mD3dpp.PresentationInterval = D3DPRESENT_INTERVAL_DEFAULT;		// v-sync ON
	else mD3dpp.PresentationInterval = D3DPRESENT_INTERVAL_IMMEDIATE;						// v-sync OFF

	OnLostDevice();

	while(!ResetDevice()) ResetDevice();
	
	OnResetDevice();
	return true;
}

// input handling routine

		if(_input.KeyPressed(VK_F4))																			// PRESSED
		{
			if(!_d3d.mSettings.GetVsync()) _d3d.SetVsync(true);
			else _d3d.SetVsync(false);
		}
		

Update: I found it, after resetting the device, I wasnt't 'resetting'/initializing my state machine.

So all d3d states (render, texture, sampler) were los and not recovered, all good now (probably texture filtering).

Thanks again for helping me in the right direction.