View Full Version : - AGP 8X Vid. Cards Backwards Compatible?

11 November 2003, 11:16 PM
I'm looking to get a new video card, but my computer's mobo. has an AGP 4X slot. Almost all the cards out there are AGP 8X -- all the good ones anyway.

I've heard that all 8X cards are backwards compatible to they're not, and will fry the mobo. So, I'm confused. Can anyone tell me for sure?


11 November 2003, 01:38 AM
cant help you with your problem. but i gotta say i never used to have problems with agp was was wondering why anyone ever thought that pci-x would be a good idea.. until my agp blew out on me... now im back on my old machine and i cant use my better videocard because the agp is only 1-2x on the mobo.. but the videocard is 4-8x :/ i guess the pci express will be a better standard that wont change every two days.. should be nice. ( especially if one pci port blows.. you always got the other however many ports..:)

:) just passing through.

11 November 2003, 03:11 AM
CIM: They *should* be backwards compatible. The thing that you are going to have to look out for is the voltage of the card and the voltage of your system board. If those are different (i.e. one is 3.3V and the other is 5V) then you can end up frying things. If they match or the card is compatable with both then you won't have a problem. The cards/motherboard should also be keyed so that you can't put the wrong voltage card into the wrong voltage slot.

ambient-whisper: You will still have a speical PCI-Express slot for the graphics (longer than the others) that in essence has more channels dedicated to the card. So your graphics card might have 4 channels, which allows for the bandwidth needed for graphics, while your sound card has 1 channel and a different sized slot. In short you won't be able to slap your PCI-Express graphics card in any of the PCI-Express slots on your system. This also unforutnatly means that you will not be able to have mulitple PCI-Express graphics cards in the same system running at their full preformance just the same as you can only have one AGP graphics card today.

11 November 2003, 05:43 AM
If voltage matters, then why don't the vendors list it in the video cards specs?

How do I find out my computer's voltage and the cards voltage?

11 November 2003, 01:12 PM
Try to see if you can download a manual of the board and card, it will be in there.

Really though if you are only dropping down to 4x then you probably won't have a problem.

11 November 2003, 02:02 PM
Originally posted by CIM
If voltage matters, then why don't the vendors list it in the video cards specs?

How do I find out my computer's voltage and the cards voltage?

Hi Cim,
usualy there is a small plastik ridge inside of the AGP slot that prevents you from using cards with the wrong voltage. There are only very few (and rather old) cards that ignore this and my cause damage. If your card and Mobo is not older then 2 years there should be no problem. Personaly i never encountered this situation although i have been an IT services freelancer for over 10 years.


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