Why are you posting this on the forum, when you know fully well you have been in contact with support for several weeks by now, and I event sent you A VIDEO I made SPECIFICALLY FOR YOU, showing the problem doesn't happen ?
CYVR is fairly big and takes lots of memory and, especially with FSX SP2 ( which has bugs that FSX-Acceleration doesn't have ), so it's possible your settings to max with 4K texture is the issue.
If you really want to keep using FSX, AT LEAST update it to the latest version, the Steam version, which has several bugfixes and even some memory optimizations. It is currently ON SALE on Steam for like 5$, I'd buy it only to keep it as a backup when your DVD drive will fail, but most importantly because it's the latest FSX version which has even been updated recently by Microsoft, and it has less visual bugs than FSX-SP2.
Also, you can try switching to DirectX 10, that might save you some memory, because DX9 apps waste RAM because they keep a copy of the textures in the VRAM, stealing even more precious space from the already limited space of a 32 bit app like FSX.