Upgrading the video card will give you almost exactly zero improvement in rendering speed.

Rendering speed is almost entirely proportional to processor speed. Fast drives and extra RAM help some, but not much.

Great, thanks to John and Cjenwork. So I will just save money for the future system. I assume video card will help with playback quality, and maybe that is all?

Yes, video card will only help if you want to preview in Best Mode. I also heard that having a alot of ram (i.e. 1gig) wont really help since Vegas only uses 300? and something amount of ram.

Do you have any unnecessary programs running in the background while you are rendering? I shut down everything not needed at the time and that seems to speed things up.

If you have your pc connected to the internet you might consider killing the connection (or don't have the internet on your edit station at all) while rendering. You are probably aware of this but it doesn't hurt to mention spyware etc that creeps in and hogs resources. If you don't already, scan for that garbage and get rid of it.

Good luck....

Yes, I ususally do a re-image of my machine every few months from Ghost image to make sure I have a clean system. I do not use any virus software because they slow down the machine significantly.

Typically I shut down all my applications and leave the machine running over bight when rendering.

Check with the vendor of your system to see if the motherboard is compatible with a faster processor. Even since building my own system (it's actually pretty easy to do), I NEVER buy a "new" system; I just upgrade. Add a bit more ram, add a faster processor, add a faster burner...

Even if your PC was made by Dell or Compaq, there might be room to grow. A new processor chip is probably under $100.

From my own experience with running RAMpage, a ram usage monitor, any memory over 384MB is wasted in Vegas unless you are doing some really complex rendering, or are running multiple renders at once.

I built the machine by buying components. The motherboard can only support 1.2GHz max. So I will need new motherboard and new memory if I were to upgrade CPU. Sometimes dell run amazing deals, very enticing. But do not know how that compares to DIY machines,

First, let me just say that Dell PCs generally SUUUUCK compared to a good DIY machine. They have very limited expandability due to proprietary motherboard and power supply configurations. And their BIOS is generally pretty limited.

Now, let me also say that an inexpensive Dell PC can kick ass and do more than you need. If you're not interested in future upgrade capacity and don't want the hassle of a DIY project, Dell is a good choice. And did I say inexpensive? Considerably cheaper than DIY.

In fact, I almost bought one yesterday just for fun. They've got an amazing deal going (through today 12/21 only, however,) on a Dimension 3000. It's a low-end budget PC, but you could definately edit on it. Check out the specs:

Pentium 4 2.8Ghz
512 MB RAM
80GB 7200 HD
Onboard audio
CD burner
Windows XP Home

All for $349. And for $100 more you can upgrade to 1GB RAM. Heck, it's tough to even buy just 1GB of DDR RAM alone for less than $400. And if you want a 15" LCD., you can add one on for another $100. Check out their Small Business section on the web.

Depending on how serious you are about editing buy as much horsepower as the mortgage will permit. I know with every CPU the speed increase per dollar is very exponential however from what I can see so too is the impact on performance with things like playback.
Taking the simple view, a 8% increase in CPU power may not seem much return on doubling the cost of the CPU. However, it may well make the difference between achieving RT playback or not. The CPU only needs to miss the boat delivering a rendered frame by 0.001% for the fps to drop. When it comes to rendering to a new file then the difference is linear against CPU speed and if that's all you're worried about then go for the optimum price/speed tradeoff.
Bob.