|A better video card will NOT significantly improve the performance of your computer, it will just make the performance of the video better. If you think your computer is slow, a better video card won't help for that much. |
Go to a web site that has relative benchmarks of the performance of the different video cards (video chipsets).
This one - it shows you approximate prices of the cards on the right side in many cases.
The computer case of your desktop computer IS NOT A CPU !
CPU - Central Processing Unit
You usually CANNOT upgrade the video on a laptop or netbook.
The max (output) wattage capacity of your power supply MAY limit which video card you can install without needing to upgrade the power supply to one that has more capacity.
Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.
Some desktop cases have limitations regarding the max length the video card can be, or require a low profile (shorter) metal mounting bracket on the video card.
If you want more specific info, you need to .....
Tell us the make and model of your brand name system, or if you have a generic desktop system, the make and model of the mboard.
The model, sometimes the make, of a mboard in a generic desktop system is usually printed on the mboard's surface in obvious larger characters, often between the slots.
The specific model of a brand name system is often shown on a label on the outside of the case somewhere, or it can often be determined by going to the brand name's web site and loading a program they have available, if Windows is still working, on the subject computer.