How does adding an SD Card boost performance?

I have 1.5gb ram with vista and windows-7 installed.

what would adding a 4gb class 6 SD card do exactly?

 

Nothing special. Will give you another "drive" with 4GB of available space for data...

 

Lol, I think he means with Readyboost/eBoostr or something.

It creates something like a pagefile, I believe, but it's faster than the actual Windows pagefile. It's slower than RAM, but faster than PF, so I guess the programs use the SD card before going to PF?

 

yes that's what i meant.

it doesn't seem like a worthy 'upgrade'

 

If you have a spare SD card lying around, you might as well put it to use. I believe ReadyBoost relies on an efficient superfetch, which, depending on your usage, may take some time (on the scale of weeks/months) to develop in order to make the benefit more apparent.

 

SD card is about 100 times better than your regular harddrive in terms of access time speed measured in miliseconds. Readyboost is basically "pre-start" your programs and put it in the SD card. Due to the extremely low access time and fairly good throughput, programs "stored" on the SD card in an encrypted, compressed form, should load significantly faster than if it was loaded from the HDD. This "pre-start" program process is mostly handled by another program built into windows called superfetch which as the name suggests fetch the data, a.k.a pre-start your frequently used program for you.

The performance difference is dependant upon what program you use and how many program you use regularily. You should notice quite a bit of performance boost if you use programs such as adobe photoshop or adobe acrobat on your AAO.

 

so i should install photoshop in an sd card if i can?

 

ahm, no.
If you use apps with heavy hdd load like photoshop you should try readyboost (only in winvista) or eboostr (working fine with almost all win OS) to speed up your work.
readyboost or eboostr gives you a "clever" pagefile (stored at your sd card) for prefetching most wanted files.

 

and those "page file" stored on the SD card is different from those stored on the HDD. Readyboost select a few files from the page file that are smaller than a certain size. Since flash storage can be a couple times faster in transfer small files than HDD due to the low access time, readyboost can really put your flash storage to good use.

If you just put your page file on the SD card, you'll actually notice quite a bit of performance drop because SD card is so much slower compared to HDD for sequencial read/write and large read/write.