Firstly, Gizmo is required. Secondly, everything you specify is indeed related to memory exhaustion. It was an off chance that removing Gizmo appeared in your eyes to momentarily solve this, but as one other person in this forum also found out, Gizmo is in no way the culprit. In the end it was his large custom scenery folder and high settings. The 560 is likely getting further constrained with XP's hefty requirements. The displays are drawn on the GPU, and short of starting at the BARE MINIMUM (low resolution) settings in X-Plane and slowly turning things back on/upping resolution I have no further suggestions for you. Laminar will alleviate most of this pain with the introduction of X-Plane 10 64-bit. Until then, it's a battle for some, a non-issue for others.