I'm not really sure what you mean with "freeze". If you mean transfer stall, it may be many different things, unrelated to network itself (layouting the page can take time, for intance). But 10s really seems like a LOT, though. Never saw that on my rather slow 8Mbps link.
As for your 24Mbps speed, it's actually not slow at all, it's really good, even. OWB itself has nothing to do with download speed, it does as much as the TCP stack allows, and since Netstack doesn't support TCP window scaling, you can't hope to get optimal speeds from inet (on LAN you will, of course).
As for wookiechat taking 15 minutes, it's very likely something else, use a less buggy client like Amirc. I would also avoid using amigift, it was really quite buggy last time i saw it.
