I know that I have a bad habit of never closing any of my windows, and I currently have 10 tabs on my IE bar, but my machine is showing 50% cpu usage in 71 processes (I run a core 2 duo 2.2 with 2gb RAM) oh i’m also running XP.
Does having alot of open documents really tax my system that much? Is there something working in the background I’m not aware of?
IE can be a real hog – I usually have about a ten windows open, and if i sort by mem usage, often they are 70k each.
Looking at processes and sorting by mem usage should give you an idea of what is going on…
If you bring up the Task Manager and then select the ‘Processes’ tab, you will see a check box in the lower left to list all processes, not just the ones you started. Sorting this list by CPU utilization will tell you if there is anything running in the background (anti-virus scans, etc.) that’s chewing up cycles.
If you see more than one IExplorer processes in your process list, you are not using your computer efficiently. You should NOT launch a new Internet Explorer for visiting a new page. You should either open a new window (CTRL W) or a new Tab (CTRL T) for IE 7 or FireFox. An extra process has a lot of overhead on the system (including but not limited to extra memory usage) and slows things down.
As for the memory usage of IE 7, in fact it might be slightly better than FireFox in its physical memory usage.
To answer the OP’s question, The tab browsing is pretty efficient and should not be overloading your system by too much (of course depending on the contents of the pages (10 tabs streaming high quality video for eg.), the overhead varies but for normal web surfing it is not an issue).
The CPU usage you are observing is on the other hand on the high side, it is possible that you have other processes and services doing things in the background (Windows Desktop Search indexer for instance). If soon after you close your browser, everything simmers down, then you should be looking into installing new updates, checking for spywares and verifying the add ons you have installed, for memory leakage. In its healthy state, you should be able to open twice as many tabs as you do now in IE without much noticeable performance tax.
CPU utilization is typically not related to how many programs you have open, unless possibly if you have SO many open that you’re page filing back and forth to the HD alot. CPU utilization is typically caused by something running and 51% usage is A LOT.
I know that older Firefox version did some funky CPU utilization on occasion so I’m sure other programs do as well, but that’s abnormal so it shouldn’t be that way.
For instance I’m running XP on a core Duo as well. I have Firefox up and running with 12 tabs open, as well as Excel, an accounting program, Thunderbird for E-mail a couple explorers AND Autodesk Inventor with a small assembly opened in it.
My CPU utilization is at 99% System Idle Process, IOW I’m using 1% of my CPU. My memory usage however is at around 60%. With all of this open I only have 40 processes open.
Just a WILD guess either you’ve been infested with spyware or a virus. Typically what happens is they start firing off process after process doing all sorts of things that are CONSTANTLY running until they bring your system to it’s knees or you have a piece of software somewhere that is screwed up and is chewing up CPU cycles…oh or you forgot you’re rendering a video in the background 
One other thing, you’re not running some sort of “Peer to Peer” calculating project are you? Something like Folding at home or SETI? That would do it too, but they usually try and spike you at 100% CPU usage.
Easy way is as someone else suggested, pull up the task manger and look at processes. If you have some funky ones in there like 1toobig.exe or 1OO@!too.exe you may have issues. Many are disguised to look like real processes so they may not jump out at you.
~Matt
If you see more than one IExplorer processes in your process list, you are not using your computer efficiently. You should NOT launch a new Internet Explorer for visiting a new page. You should either open a new window (CTRL W) or a new Tab (CTRL T) for IE 7 or FireFox. An extra process has a lot of overhead on the system (including but not limited to extra memory usage) and slows things down.
I’m still on IE6…I need to upgrade…