The tiling issue happens on all shots with resolutions higher than your current viewer render resolution. It's a known issue since last year when i reported it. FS has yet to fix it, i did report it in time for them (and LL) to fix it. BD had it fixed immediately after it was reported (4 days later) in November? October?
Texture trashing means you are running out of available texture memory. This is either because you've set your texture memory too low or if you are using automatic memory