video card upgrade

I have Dell system I purchased in early 2006. It actually still runs quite well with minor upgrades (and some occasional software help and rescue from Major Geeks).

It is running Windows XP Professional / Medica Center with SP3 and has the following specs:
- Intel Pentium XE 830 processor (dual core) at 3.0 MHz, 1MB cache
- 4 MB DDR2-SDRAM

My power supply is currently a puny 375W but I was told a while back that the funny way Dell made these cases I might not be able to fit anything bigger.

My current video card is an NVidia GeForce GT240 with 500MB RAM

My current Dell 1704FPT monitor is 1280x1240 pixels

I want to upgrade my video card and keep it under $150, even better is under $100.

My main intention is to edit MP4 or AVCHD videos (currently I use Magix Movie Edit Pro) without stutter in editing or playback.

How do I find out the best and compatible video card I can buy?

Thanks

 

I meant to include this system query, in case it is helpful:

General Information :
Manufacturer : Nvidia
Model : NVIDIA GeForce GT 240
Bus Type : PCI-Express
Texture Memory : 1004MB
Processor : GeForce GT 240
Converter : Integrated RAMDAC
Refresh Rate (min/max) : 60/75 Hz

GPU Information :
Number of GPU : 1
Processor : GA3
Codename : Telsa
Revision : A2
PCI Express : @ x16
Mobile : No
Bus : 128-bit
Memory Type : 512MB GDDR5
Mode ECC : No
Number of Core : 96
Shader Pipe : 4
SM Unit : 3
SM Total : 12
GPU Frequency : 135MHz
Memory Frequency GPU : 135MHz

GPU Configuration :
ForceWare Version : 6.14.13.0681
Technology SLi : Yes - Disabled
Number of GPU SLI : 1
AA Mode : OFF

External Connectors :
Connector Type : DVI-I - (Place : Socketed)
Connector Type : VGA - (Place : Socketed)

Video Bios Information :
Date : 09/02/10
Version : Version 70.15.2C.00.40
Forceware : 6.14.13.681

 

Follow-up:

I found a TX650 corsair PSU on sale at newegg, which I will get this weekend and install, so now I don't have that limitation.

For under $100, I can get a GTS450 EVGA card (on sale for $50 after rebate) - will that provide a noticable upgrade over the GT240? Any other sub-100 recommendations?
Do I need to go GTX or equivalent, or will my processor still be a bottleneck?

Thanks again for any input

 

A GTS 450 is an upgrade, how much of one, not sure.

From this site: http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-7.html You can see that your card is a couple tiers up.
But, best for the money is: http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-2.html

 

I would save your money and look into a new computer. I don't think a new video card is going to help you much. For doing video editing a new CPU would be a major upgrade but tit sounds like that isn't going to happen with this pc.