|There's no such thing as a 30 bit video output as far as I know - 32 bit , yes|
All modern video cards and displays support a 32 bit output.
If you're using a high end photo processing program, it may place more of a load on the video adapter than a high end game would.
Look at the benchmarks for the video cards.
The approximate prices are often shown on the same line.
Buy one with the highest benchmark you're willing to spend the stated money for.
When you search for a video card with a particular video chipset, there may be cards that are on sale or that have a mail-in rebate for a limited time.
But - keep this in mind
- if you have a small form factor computer, you need to buy a video card that has the low profile bracket(s), or that has both the regular bracket (taller) and the low profile bracket(s) (shorter) included with it.
- you may need to upgrade your power supply, or limit yourself to cards that will be okay with your existing power supply 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, OR, if the max total amperage or watts at +12 v is stated, go by that instead (max watts at +12 v divided by 12 = the max amperage at 12 v).