Save RAM Wear - Does it?

slobu · Post by **slobu** » Fri Mar 23, 2012 12:14 pm

Does frequent writes/reads of battery backed RAM wear out anything? Use more juice?

Do flash carts suffer any wear from emulated battery RAM access? I mean, they shouldn't immediately write back to flash, right?

Shiru · Post by **Shiru** » Fri Mar 23, 2012 12:16 pm

Normal, not emulated battery backed RAM is just a RAM that is battery backed. So it does not wear, just like usual RAM.

tokumaru · Post by **tokumaru** » Fri Mar 23, 2012 12:55 pm

And you can't use Flash to emulate RAM. If a Flash cart supports SRAM, it must have RAM in it.

MottZilla · Post by **MottZilla** » Fri Mar 23, 2012 1:43 pm

You might be thinking about FeRAM which is used in some EverDrive cartridges for SRAM. FeRAM has a limited number of write cycles (not read cycles) and will wear out. The developer said when monitoring SRAM use he saw games generally don't do things that would wear out the memory that fast.

SRAM is just "Static RAM" which has no limit of reads or writes. Atleast, no more or less than a CPU has a limit of cycles it can execute.

FeRAM and Flash, and EEPROM are types of memory with a finite number of write cycles. Usually the number is high enough that most users won't be affected by the eventual failure.

Shiru · Post by **Shiru** » Fri Mar 23, 2012 2:01 pm

I think it is worth to note that despite 'RAM' in the name, FeRAM is non-volatile, so it does not need battery backup.

tokumaru · Post by **tokumaru** » Fri Mar 23, 2012 4:06 pm

MottZilla wrote: The developer said when monitoring SRAM use he saw games generally don't do things that would wear out the memory that fast.

Maybe on the Genesis, but NES games use SRAM as regular RAM quite often.

kyuusaku · Post by **kyuusaku** » Fri Mar 23, 2012 4:36 pm

Does frequent writes/reads of battery backed RAM wear out anything? Use more juice?

If by juice you mean current from the battery, frequent writes/reads actually uses less because when the cart is in console and powered on the current comes from the console, not the battery. Note that this isn't significant however because the batteries are not rechargeable.

Post by **tepples** » Fri Mar 23, 2012 5:06 pm

In some of the GBA flash cards, the SRAM's "battery" is actually just a big capacitor so that the cart can be power cycled (GBA has no reset button) to write out the contents to flash.

MottZilla · Post by **MottZilla** » Fri Mar 23, 2012 11:37 pm

tokumaru wrote:
MottZilla wrote: The developer said when monitoring SRAM use he saw games generally don't do things that would wear out the memory that fast.
Maybe on the Genesis, but NES games use SRAM as regular RAM quite often.

Right, I was specifically talking about the EverDrive products for Genesis and SNES. Apparently most SNES games do not make rapid use of SRAM but I think you would expect that with its massive 128K of RAM.

slobu · Post by **slobu** » Sat Mar 24, 2012 8:33 am

Thanks guys! It sounds like, if I have the luxury, use some real RAM as a buffer and then back it up to save RAM only when needed. I had an idea for a game that would rely heavily on save RAM but wasn't sure about wear.

kyuusaku · Post by **kyuusaku** » Sun Mar 25, 2012 9:05 am

slobu wrote:It sounds like, if I have the luxury, use some real RAM as a buffer and then back it up to save RAM only when needed.

This, except the opposite. There's literally no penalty to using on-cart SRAM, which is real RAM. Without having to double buffer memory your game will be faster and without waiting to flush data to the cart RAM a user has a better chance of their save surviving a random power loss.