Loss of memory from RAm

Hi,

All power supplies have capacitors in them to smooth the power and give a constant supply. These capacitors will hold a certain amount of charge - enough to power the PC momentarily after the power goes off - if only for a moment.

To answer your question, you need to know the specs of your power supply. They're all different. Larger better ones will power it for longer...

But if you simply want to know the answer from the SDRAM chip's point of view... SDRAM chips need to "refresh" themselves frequently to keep their data intact. This is done internally.

The refresh rate according to Intel's SDRAM specs found at...

http://developer.intel.com/technology/memory/pc133sdram/spec/sdram133.htm
(remove spaces from the above URL)

...is either 15.6 or 7.8 microseconds per "row" (7.8usec for 256M memory)

Obviously the number of rows is dependant on the size of the SDRAM chip but it'd be safe to assume it would be 16,000 for a 256Mb chip (16,000 x 16,000) = 256Mb

So the refresh rate minimum would be 16,000 x 7.8usec = 124800usec or 0.125 seconds

This is the specified minimum but it would be safe to assume that the engineers had built a little safety in that figure and so it would be perhaps the order of 0.15sec before data would be lost.

Hope this helps,
Cheers,
Tim.

An interruption in power of as little as .02 seconds will cause computer and/or memory errors

Put a UPS pn your computer and you won't
have to worry about crap like that.

This question was auto closed due to inactivity