hey,

Is it possible to turn memory from an sd card into ram?

That is essentially what swap space is used for, but you aren't technically replacing RAM. Swap space is used when the system runs out of actual RAM; but it is much much slower than real RAM, it is used as a last ditch effort to keep the system from locking up or losing data. It is not acceptable for full time use.

Especially flash media, which would be even slower than on a standard HDD.

IF you had a SD card reader that did not go through usb it would not be as bad.

True, but you do not want to use flash memory as swap due to the limited number of write/erase cycles and also its write speed being slower then a physical hard drive.

Most internal SD readers are still on the USB bus, so the speed difference wouldn't be any different.

At any rate, the USB part of the equation is not what limits the speed of using SD, it is the fact that SD simply doesn't have very fast read or write compared to other storage technologies, certainly not enough to saturate a USB 2.0 reader.

I guess my assumption was that he was maxed out on the motherboard for ram, indicating older technology. That probably would mean USB 1.0 which maxes out at 1.5 MB/s. Many of the newer SD cards are 15 MB/s or faster. There are also a number of companies that sell SD to IDE adapters. The limitation seems to be in the SD cards themselves as opposed to Flash.

http://www.newegg.com/Product/Produc...82E16820313023

The rewrite issue has been mostly taken care of now by the controller on the chip. It spreads the writes across the drive rather than continually rewriting in the same spot.

This is true if the card is being used for normal storage, but I wouldn't think it true if it was going to be used for swap, especially if there is limited real memory in the system.

Of course, I could also be wrong.

Forrest

Hi,
My first question is what you would be using the SD for? As indicated a swap is for moving data/information in/out of system RAM.

There's nothing wrong with using a SD/Flash or other memory device for intermediate storage space. Heck, you can setup a ramdisk to speed exchanges between applications. That is done all the time, especially with servers.