Playing with Linux 2.6

Since my brother messed with my computers (and whenever he does something he's never done before or when he doesn't think about consequences he breaks something), I had to fix a few things on the gateway, and so I decided to switch to Linux 2.6.0-test9, the latest version of the test series of the upcoming 2.6 kernel. I already played with this kernel on my desktop machine (at home) and my workstation (at work), and I only made good experiences, i.e. the kernel was performing very well, and the whole system generally felt smoother and more responsive. The catch with the gateway: it's an extremely old machine (Pentium 133 MHz) with relatively exotic hardware (passive ISDN card) whose driver support is marked as "obsolete" in the Linux kernel. So, I'll see whether Linux 2.6 will really perform better than the current 2.4.19 kernel, and what is even more interesting, whether ISDN will still work.