[Q] Kindle is slow since new ROM

I have a rather annoying problem with my first generation Kindle. Now, that I have successfully installed a new ROM to my device in order to run apps, which was not working earlier, I found out, that my device is critically slow. It is exceedingly lazy, when it comes to surfing on the internet, it is almost impossible. To the top of that, however, I can install applications now, but a lot of software quits. It looks as if it ran out of memory. For example I couldn't load a map in Free Heroes 2, it dropped me to the menu list. Running that game shouldn't be a problem to this hardware, should it? What could be the problem? For the record, I have BeanStalk 4.1.2 running on Kindle. Thanks for help in advance.