teahousemoon - it's actually pretty difficult to measure VRAM, you generally need specialist tools from your GPU vendor to do it. It's also complicated by the fact often GPUs can share some (but not all) memory with RAM, so the reported memory use/capacity may be larger than it actually has on-board. GPUs tend to have much smaller on-board memory than typical for system memory, e.g. 256mb or 512mb, while system RAM is often 4 GB+, so it's much more likely the GPU runs out of memory before the system does.