I was admiring my new 5500 board yesterday and noticed the NEC PQFP VRAM chips. They look just like the Samsung KM4132G512 chips I have on hand. So I checked the Hardware Developer Note for the 5500/6500 and it is indeed SGRAM, which means that it is almost certainly pin compatible (there are JEDEC standards for most memory pinouts). I still need to find the datasheet for the NEC part and compare.
So the question becomes, has anyone tried increasing the VRAM capacity on one of these things to get more color depth or video resolutions? Apparently it all depends on whether Apple connected pin 30 of the VRAM chips to a memory line.
The 100 pin QFPs aren't all that difficult to solder/desolder especially if one does not need to reuse the old ones.
So the question becomes, has anyone tried increasing the VRAM capacity on one of these things to get more color depth or video resolutions? Apparently it all depends on whether Apple connected pin 30 of the VRAM chips to a memory line.
The 100 pin QFPs aren't all that difficult to solder/desolder especially if one does not need to reuse the old ones.