Yokemate of Keyboards
Posts: 2794 from 2006/3/21
From: Northern Calif...
Quote:
Neko wrote:
@amigadave
To use more than 128MB RAM you need to change the way the RAM is routed to the SoC; the board is prepped to take 128MB in 2 chips.
Adding 4 chips and increasing the RAM size means changing some of the lane such that instead of 16-bit per chip, the RAM is routed 8-bit per chip, to make a 32-bit DDR bus.
Interesting........ then that should not in itself prevent a memory upgrade where the two 64mb chips giving a total of 128mb of existing RAM were removed and replaced with two 128mb chips for a total of 256mb of RAM placed in the exact location as the previous original RAM chips had been installed, correct? That would not change the "lane", or require any pcb change with regards to the 32-bit DDR bus.
Quote:
Neko wrote:
You'd need a new PCB with the correct layers. The solder pads on the underside are just 'for show' - they don't work unless the other layers match (just that etching the top layer is done exactly the same for any PCB that was made).
Very odd way to produce a motherboard, that it would need to be redesigned and have different etching or pathways on interior layers to accommodate different RAM amounts, but you would have access to that information, where the public does not, so I will concede that adding memory to the pads on the underside of the Efika is NOT possible.
Quote:
Neko wrote:
Add to that, the firmware needs modifying to set up the RAM with the new PCB and whatever new RAM chips appeared. The reason it was stuck at 128MB was a design decision to keep cost low; at the time the original was designed, ~512MB of DDR RAM was prohibitive and most of the chips in the configuration that was most efficient would have tripled the BOM cost of the board.
Hmmmm....... switching from 128mb of RAM to 512mb of RAM would have tripled the cost of the materials of the Efika board at the time it was released? That is another surprise that it would be that much more, but if the actual material cost was approximately $20 to $25 (I can't see it being too much more since the end cost of the Efika board from Directron is only $99), then the tripled cost would be $60 to $75. The price to manufacture the Efika pcb's would have been the same, so that would not have increased the end price of the Efika, the profit margin would have increased, but not tripled, the shipping would have been the same, taxes would have slightly increased, so all said and done the final price of an Efika board might have gone from $99 up to perhaps $160-$199 for the 512mb version. I can see why the decision to stay with the lower spec'd version was made, as the sales of the more expensive model would have been limited to perhaps only half, or a bit more of what the sales of the Efika for MorphOS use were at the $99 price point. Much too low to make it economically feasible.
Still, if possible in ANY way (such as replacing the existing RAM with double the amount of RAM in the same location as the existing) increasing the amount of RAM on the existing Efika boards would be a welcome modification and I would be willing to work on any firmware modifications that would be necessary to make it possible, just because it would be a good thing to do. This is assuming that the correct RAM chip replacements could be found at a decent price.
Thanks for the clarification regarding the Efika mainboard layers which are different, depending on what RAM design is chosen at the time of manufacture of the pcb.
MorphOS - The best Next Gen Amiga choice.
