If you watched my Captivate review earlier last week, you'll know that I like the phone's hardware, but couldn't stomach the jarring screen lag and interminable pauses that plagued the phone. However, my Captivate now runs stupid-fast, thanks to some intrepid Android hackers at the xda-developer forum--first mimocan figured out how to fix the problems with the phone's filesystem, then Tayutama made the fix relatively simple to install. You'll need to root your phone in order to apply the fix, which does (theoretically) void your warranty and could brick your phone, but the process is relatively safe and simple enough that anyone can do it. As long as you're running this fix, you'll lose some app storage space, but that's a small price to pay in order to turn the Captivate into a usable, crazy-fast phone.
crapware removal guide for the Captivate. Once you've rooted the phone, download the the lagfix file here and copy it to the root of your Captivate's internal SD card. Then, power down the phone, hold down the volume up and down buttons, and then press and hold the power button, until you see the Galaxy S screen. Continue holding the volume up and down buttons, but release the power button. Just as it did when you rooted the phone, this will take you to the recovery menu. Navigate down to Reinstall packages using the volume up and down buttons, then select that option by pressing the power button. The phone will install the hack, then restart.
Next, open up your app browser, and start MCR Scripts. Click on either LagFix1024.sh (if you had 1GB of space free) or LagFix512.sh (if you had 512MB free), and the script will create a properly formatted virtual drive inside the phone internal app storage. This will take a while--it took about 15 minutes on my test phone. Once the process is completed, reboot the phone and it should be lightning quick. WARNING: Before you install any patches, be sure you revert this change, using the Uninstall script in the MCR Scripts app. That's it, enjoy your new crazy-fast Captivate!