I've been using MC 1.2.5 with IC2 1.9B to be able to play with Tropicraft. When I noticed that IC2 came out for 1.3.2, I saw millions of bugs. The one that mostly caught my attention was the cable error. I looked through the Bugs section and saw that the error was from 1.103. I went to the wiki and read this:
I can honestly say that I have a terrible PC, MC will only work with settings as low as possible and still lag with FPS around 4-6. But I prefer a CPU whore that works like a charm rather than a CPU-saver that works in a not-so-good way. Although this bug is great to reduce resource usage, it kills the fun of being stuck deep underground, mining for ores.