The performance penalty for paging in data from system RAM is already high enough that most games are highly optimized to keep the necessary data in GPU RAM. Pa

The performance penalty for paging in data from system RAM is already high enough that most games are highly optimized to keep the necessary data in GPU RAM. Paging in random bits of data is more latency-sensitive than bandwidth-constrained. I'm not surprised that the penalty is ~25%. Using the eGPU to drive the internal panel means copying the frame buffer back to the internal GPU which is where the latency and performance penalty come from; I'm not sure how it is implemented, it might actually be copying twice (once to system RAM, then again to the discrete GPU RAM). Having more lanes over the TB connection would probably help here, though it might not eliminate the latency.