memory card for virtual memory?

mac_angel · Sep 27, 2007, 11:07 PM

I have a Dell XPS-M1710 with 4GB of RAM installed and a 200GB 7200RPM hard drive. Right now I have the virtual memory set to 2GB. I've been toying around with the idea of buying a fast SD card and keeping it in the memory card reader to use as a virtual memory drive (thought about doing this even before readyboost). I can find pretty fast and pretty cheap SD cards, but I'm just wondering if it really would boost system performace, if at all. Anyone have any thoughts?

Tipstaff · Sep 28, 2007, 01:07 AM

Readyboost is a joke. The only advantage it has is for systems with less than 512MB of memory. Once you go above 1GB Readyboost gives marginal to no increase.

That aside, here's something to consider: your memory card reader is probably USB driven, correct? If you decide to transfer your page file to an SD card remember that the memory card reader would be, at it's maximum speed, transferring data at USB speeds of 480mbps. That works out to be 60MB/s. Comparatively, thats slower than a UDMA66 IDE hard drive. Another factor to consider is the speed of the SD memory card itself. On average most cards are rated at 66x, or 10MB/s with others running at 133x, or 20MB/s (more expensive ones will run 150x). As you can see your performance will go down the toilet.

With the amount of ram you have, and the speed of your hard drive, you would actually be hindering performance. Your better bet would be to grab another hard drive (for best performance maybe a 10k or 15k rpm drive), and move your swap file to it instead.

mac_angel · Sep 28, 2007, 02:32 AM

yes, I know readyboost is a joke, but it's only really for expanding your RAM, not replacing your swap file.
sorry, I guess I should have explained that it's a laptop. It's on my signature I believe, but for some reason it's not showing up.
So with that said, only 3.25GB of the RAM is usable by the chipset for the OS (rest, I read, is suppose to be still use, just as hardware resources such as the video card - no, not shared memory).
ATA and even SATA can have a speed of 133 and up but that doesn't mean that's how fast the hard drive actually transfers data. I do realize that a hard drive is still faster than a 150x SD card but that's specifically for sustained read/write. What I'm pondering about is instead of the hard drive doing multiple searches, reads and writes with the OS, games, etc, if using an SD card specifically for the virtual memory if that would be faster than the hard drive itself multitasking.

mkk · Sep 28, 2007, 02:55 AM

Unfortunately the system probably won't even allow for placing a swapfile on the memory card. Try it with a regular USB stick and you'll probably see that it doesn't show up amongst the available choices. On the other hand with a good amount of RAM your system will typically not use the swapfile very much.

mac_angel · Sep 28, 2007, 12:33 PM

Quote:

Originally Posted by mkk

Unfortunately the system probably won't even allow for placing a swapfile on the memory card. Try it with a regular USB stick and you'll probably see that it doesn't show up amongst the available choices. On the other hand with a good amount of RAM your system will typically not use the swapfile very much.

I think that's a matter of formatting the stick or card. I did just try it with one of my USB keys that is actually formatted as a boot disk and it was recognized and available to use for virtual memory.
I think I'm going to buy a new USB key today, a really fast one, and give that a try, see if it helps. Then I'll know if the SD card will help or not.
Anyone else ever tries it I'd love to know what you think.

mkk · Sep 28, 2007, 02:00 PM

I remembered that incorrectly, it does indeed show up in the list. However no pagefile is ever placed on the USB device. I'd assume that USB devices are enabled too late into the operating system startup process to qualify for hosting a pagefile.

Edit: oh wait a minute, after clearing the page file record in the registry and going back to the system settings a file does finally show up on the USB stick. I'll have to try it more and see what happens. Edit2: Nah, the file is there but the system never begins to actually use it and the registry entry for the list of pagefiles gets garbled characters in it. Instead the system reverts to default behavior and creates a dynamically sized file on the system drive.