I'm using built-in ethernet and SBC DSL with IP setting of 68.78.114.215
That's just your IP address - is there anything configured in the DNS server section? If not, try adding the two IP address mentioned earlier. It does seem to make a difference, for Safari anyway.
I still think there's something else wrong with your machine. I have an Intel Mac with 2GB RAM, and MS apps - which are running in Rosetta - are not noticeably slower than my PC at work. I certainly don't do much waiting. They should be faster on your dual G5 since they are PPC native apps.
Do what yojitani and try another account.
And run disk utility, verify hard drive.
Can you open activity monitor and take a look at what's using CPU when it's slow? And memory usage too? How much hard drive space do you have left?
If you listen carefully to your hard drive, is it making regular sounds like, whirr, whirr, whirr, pause, whirr, whirr, whirr, pause and so on? If so, it's likely a problem with the hard drive, maybe bad sectors, which can slow things down considerably.
It's very possible to get two bad machines in a row. If there's say, 5% lemons out there, the chances of getting two in a row is 1/400, which is still significant.