Why does my 2.0ghz P-M seem so slow?

Sorry if this has been discussed before, I didn't really know what to search for.

I got an IBM t43 (2.0ghz p-m, sonoma) a few months ago to replace my dell 5150 (3.06ghz p-4). I thought there might be some slight change in performance, but most likely an improvement. When I got the IBM, it didn't seem any faster. I ran superpi for a mini speed test, though, and it performed a good big better than the p4.

However, I am not seeing this in most of my everyday use. In fact, there are some things that are noticeably slow, and I don't know if it's due to the processor or something else. The most obvious thing is when I open PDFs. It takes a little while to open them, but it takes forever to close them. And I'm talking something like 30 seconds, like enough to make me get up and do other things while it closes, and then come back to see if it's finished. It's very annoying because I have to use a lot of pdf's for my schoolwork.

There are other things that seem slower, too, but that's what sticks out the most right now. Opening and switching between programs is slow sometimes, too. Is it something with the P-M? Is there anything I can do to help it? I have/had 1gig in both systems, so that can't be the problem. I keep the programs running to a minimum, also. What's the deal?

dell 5150
3.06ghz p-4
1gb pc2700
32mb radeon 9000
40 or 100gb 5400rpm

ibm t43
2.0ghz p-m
1gb pc4200
64mb x300
80gb 5400rpm

Programs running on both are comparable. Basically the same stuff on both computers, same programs, etc, so the only big variables left to account for the change are the processor type and/or the video, and it would be weird for an increase in video ram to hinder the performance.

well, i downloaded foxit and am now using it instead of adobe. It's much faster, and I no longer have the long delays.
I think the problem may lie in the new(er) version of adobe, and possibly the adobe plugin in firefox. It may be something with the chipset or how the processor works, I don't know.

To respond to a few of the comments, though...I'm running microsoft's antispyware thing, norton AV corporate edition, keep my running processes to a minimum, and no spyware running. I know the antispyware and norton can be killers, but they were on my old computer as well, so if they were the problem, it should have been happening then also. I don't think it's the harddrive since the larger harddrive should be faster, and this didn't happen with my 40gig hd (on the dell). Happened both on battery and AC, and putting the processor on 'max performance' made no difference at all. My dell pentium 4 was not the version with hyperthreading.

So, I may not have 'solved' the problem, but it's no longer an issue. I recommend foxit to everyone, adobe has really gotten ridiculous. 60mb download for a viewer only? I'll take the 1mb foxit; much much faster.

Ok, but mine is 5400rpm.