I found some pictures of the backside of the Go 7800GTX, and although difficult to see, hidden under a cover there are 4 more memory chips.
So the Go 7800 has most likely the same layout, ergo 256Mbyte.
That Nvidia tells that the G70 chip is able to support 512MB, is proven on their 7800GTX512 board. But it does not mean that Dell's Go 7800 version can be upgraded. In fact, even Nvidia is hardly able to supply this board. It's like a paper monster being there until the G71 will be introduced, Nvidia's answer to ATI's X1900 serie.
So the Go 7800 has most likely the same layout, ergo 256Mbyte.
That Nvidia tells that the G70 chip is able to support 512MB, is proven on their 7800GTX512 board. But it does not mean that Dell's Go 7800 version can be upgraded. In fact, even Nvidia is hardly able to supply this board. It's like a paper monster being there until the G71 will be introduced, Nvidia's answer to ATI's X1900 serie.
