self explanatory here… I"m finally wanting to upgrade the processor on my tyan s1854 trinity 400 motherboard and just want to find out what the best that the motherboard can take will be, I’m just not sure where to look.
Usually your motherboard manual will state the speeds it can handle. Ultimately, you’ll need to cross reference. Find the fastest processor for your socket type and see if the motherboard will support that.
A quick Google of your motherboard shows that it’s a Socket Celeron or Slot 1 motherboard (takes both) and therefore the Pentium III 600MHz is the fastest thing it can run. In other words, it’s a dinosaur, and it is not worth doing ANY type of processor upgrade on that machine. You need a new board and processor to see any real improvement on today’s apps. Anything from the Pentium II / III era will run todays stuff slowly. If it’s too slow for you now, major upgrade is your path.
Slight deflection.Do all motherboards come with integrated video cards. If so, can you upgade your card with a seperate one.
No not all motherboards have integrated video. Last time I checked, most of the ones that do have a dipswitch or BIOS setting to disable the onboard video in favor of a seperately installed video card.
No. Generally it’s lower-end motherboards that come with onboard video - if you’re going to build a “real” computer, you buy a decent motherboard (with no video) and a separate video card. For example, on a gaming rig I just put together recently, I paid about $140 for the motherboard, and $400 for the graphics card. 
As for the upgrades, I think it depends on the motherboard. I believe that most motherboards with onboard video nowadays can still take an external card, but I hear that there have been motherboards with onboard video that could not be upgraded. I don’t know for sure; I’ve never purchased a mobo that had onboard video.
[slightly-related hijack] How do I find out what kind of motherboard I have, short of opening the case and looking for a sticker? (I’m thinking about adding RAM, but have no idea what I need. My mobo is about 4 years old.
Well, opening the case and looking for labels is the best and most foolproof way to find out what your motherboard is. If your machine came with a manual, you can check the manual to see what its chipset is (this will narrow your motherboard down to a family of motherboards, all of which should use the same RAM). Likewise, there are software utilities out there that will give you good leads on what your machine is made of. SiSoft’s Sandra utility springs to mind – it can generally tell you chipset, RAM type, and CPU family.
I want to be clear again that it’s rare to get better info from software than from the metallic etched part name/serial number on the board. The board’s factory labelling will often include a revision number that (after some Googling) will tell you which subset of features are enabled on your board.
But finding out what kind of RAM you need doesn’t require much knowledge of the motherboard; just open the case (like you’re going to have to do to install the RAM) and take a stick or two out. Note that the computer should be powered off and better yet, unplugged during any hardware reconfiguration. Write down any serial numbers on the RAM, any brand names you can find, and so on.
I told a white lie up there when I said that it didn’t require much knowledge of the motherboard. You will need to know your motherboard model to determine the maximum amount of RAM your system will support, but anything worth upgrading today will support at least 1GB, and you are unlikely to need more than that if you don’t already know what kind of RAM you have.
Now for gonzomax: zagloba is right on. If you’re looking for a new motherboard but don’t have the cash for today’s video cards (who does?) get an integrated solution now and make sure it has a PCI-Express slot (not AGP, which is already becoming obsolete) for future upgrades. I’ve built two systems for friends with the nVidia 6150 chipset, and they’ve been very happy with its graphical performance in World of Warcraft and several older games. Newer games tax its performance pretty heavily, however.