Upload texture across 66Mhz+ PCI bus with DMA may show same performance as on PC.
But which is faster, uploading a bunch of textures once at the beginning of the game or level at 10MB/s or constantly during the game at 120MB/s? Warp3D has auto texture management so it will constantly swap textures in and out of gfx memory as needed. A full bandwidth PCI bus may be usable when this is happening but with enough gfx memory it doesn't happen. Performance isn't always about bandwidth. How it's managed can be just as important.