when does that screeen appear in prehistorik?

As soon as TITUS logo appeared at the beginning of Prehistorik2.
The screen is the initial scene that a player meets.

As for bumpy, I ran a cvsbuild and it shows the same thing.
and running a cvs build /w just graphicsopt applied doesn't show that corruption. what other patches do you have applied?

I applied your graphicopt patch to a clean cvs.
Then, there was no problem in a screen as for prehistorik2.
However, Bumpy's adventure still has such a problem in a clean cvs with the optimization patch. Especially, game over scene is filled with a blue background.
I tried my latest build and gulikoza's and my clean cvs, but everything was ok.

Could you take a snapshot of what it's supposed to look like? Is it supposed to be or not supposed to be filled witha a blue background?

Well.. the blue background appeared in my working build w/ your opt patch. the color is black in a clean cvs with the patch.

Here is a screenshot.

Hmm, I'm not getting those dots or lines with cvs, opt patch, or prebuilt .65. What's your settings?

I am using the latest version of MinGW/MSYS with gcc 3.4.5.

Not a debug mode, no optimization flags... (default settings).
I hit ./configure;make;strip ./src/dosbox.exe

Here is an executable that I compiled.

I meant dosbox.conf:) I do see the lines with the attached build though.

😀 I deleted dosbox.conf so that dosbox uses default settings.

Alright, I started from scratch again, applying the diff 3 from here and am getting the corruption so I have to figure out where I introduced this bug.

I narrowed it down to an issue with rasterop, I think having to do with vga.latch.d, but I'm still scratching my head. Attached is graphicsopt4.diff, which skips everything but rasterop. Also added an optimization for the modes wd was interested in and others; old way would calc bank address on every read/write; the optimization pulls that(a multiply) out, now done in vga_gfx.cpp, where it's modified less often(on a bank switch, other twiggling).

Yes, tried your fourth patch. It doesn't corrupt anything in bumpy.
Thanks for your effort.

Shouldn't that patch for lags from cycle transitions (or a revised version) be in current cvs?

Feh, all my patches should be in CVS:) It's OK though, allows time for any bugs to surface. Why I also post patches here and not just up on sourceforge; feedback.

allows time for any bugs to surface

That's true; but the cycle transition slowdown is actually a bug. And I noticed that with that patch the sound works perfectly in any condition.
I don't know if your patch is already bug-free or if is the best way to fix the bug, however i think that something should be done.

That's one thing I'd like to see that's never done, a response on why a patch isn't included. I guess I'll need to email them to ask what the sticking point(s) is/are to find out.

Could be that some people have kinda different things to do in real life as well.

You mean everyone doesn't work on dosbox all day?..

the autocycles patch has better change to be accepted if you remove the
tinkering with the titlebar.