Why is Flash so cheap compared to ram?

[blakehew]

Just wondering what everyones opinion is on this. I can by a 2GB SD card for like 20$ from new egg but a 2GB dual channel DDR2 Ram kit costs like 200$. Why is this? Flash has a much more complex structure per cell in silicon than does ram. Dram is about the simplest structure there is 1 transistor and 1 capacitor per bit. So if dram is such a simple thing vs flash why is there now a 10X difference in price? Is it all about supply and demand or is there some other factor? I would think that flash should always be more expensive than ram, but thats pureley based on the complexity of the silicon used to make the chips? Just curious about peoples thoughts on this?

 

[Tegeril]

One is significantly faster.

 

[Molondo]

I am curious my self.

 

[blakehew]

yea ram is much faster than flash, but isnt most of the cost of manufacturing silicon chips the die size and since Dram only needs one transistor per bit vs ??? per bit for flash wouldn't the die size for ram be smaller than the die size for an equivalent amount of flash, and therefore should be cheaper to make?

 

[PurdueRy]

Originally posted by: blakehew
yea ram is much faster than flash, but isnt most of the cost of manufacturing silicon chips the die size and since Dram only needs one transistor per bit vs ??? per bit for flash wouldn't the die size for ram be smaller than the die size for an equivalent amount of flash, and therefore should be cheaper to make?

Lets think about die size...considering most ram sticks have what....8 chips on each side...that's 16 chips to get the same size as 1 flash chip. Then that should explain some of the cost.

 

[McManCSU]

RAM is dynamic memory where flash is static memory. Dynamic infers that data is frequently changing, so being able to switch quickly is ideal. Higher speeds mean that more time has to be spent on designing it to work at high speeds. Therefore, I would say the main costs are due to speed and design complexity.

 

[blakehew]

Yes but i belive the reason they use so many chips on Ram sticks is because they need to make the data path wider. most ram chips have 16 data lines so to get 64 or 128 bit wide data path you need 4 or 8 16 bit wide chips. So yes because of the way ram is packaged and because ram needs to be wider to get high speeds they use physicly more packages, and that deffinty adds cost, but how much of the cost of manufacturing is packaging vs chip die. a single flash chip of 1 GB still probably has a larger die space than the combined 4 or 8 dice used to make up 1 GB of ram. Or at least i asume so because the flash is more complex and should take up more die space than ram? My argument for cost here is mostly based on the silicon die size of the two technologys.

 

[blakehew]

No more comments on this? I figured someone might have a satisfactory answer? maybe someone in the semiconductor industry or something?

 

[RaiderJ]

Originally posted by: blakehew
No more comments on this? I figured someone might have a satisfactory answer? maybe someone in the semiconductor industry or something?

:Q

Is this a serious question?