LGA-775 mainboard w/ weird PCI x16 compatibility problems

Edit: I see I posted this in the wrong category (must have mixed up tabs after registering, or the registration process itself returned me to back to this category for some reason which I originally visited) - sorry about that.

Hello. First time poster here.

I've got a G31TM-P21 motherboard which was bought some years ago on low-budget, as well as a Core 2 Quad Q8300 CPU, a powerful but hard-to-uninstall CPU cooler (Cooler Master n520), had 2x 1GB DDR2 RAM sticks laying around, and a Sapphire Radeon HD 2400 PRO video card which should be a PCI-E x16 card.
However it doesn't fit!

It's a useless graphic card nowadays anyway, but I need to find out to trace the root of this problem so I can at least know that whatever PCI-E gear I buy will actually fit on the MB.
Picture provided below
It's impossible to place it any further to the right without either moving the motherboard (which would displace all the other ports; USB, audio jacks, standard VGA, ++) or break the metal-part of the chassis on the right. And the two black-colored PCI ports (overshadowed by the video card on picture) doesn't even have the potential size/length for the card to fit into.
Is it probably just the chassis, and so I should just break it and see if it fits then? :p

Further after fixing this physical incompatibility-issue, I would like to get a "Radeon HD 6850" video card (after first upgrading my PSU from a 300 WATT one to a 550), though this card is a PCI-E 2.1 card, and my PCI-E slot is 1.0. I Google'd a bit and people seemed to claim that the 6850 card and the 2.1 standard in general is backwards-compatible with a 1.0 PCI-E slot.
However they seemed not to agree about how much of a setback this would be, if the PCI-E 1.0 slot can provide enough power for the 6850 card to be useful at all as a video card.
Would appreciate if someone could perhaps clarify a little about this :p

5 answers Last reply
More about mainboard weird compatibility problems
  1. I *THINK* your graphics card has an AGB, NOT a PCI-E interface.
    It definetly is not an PCI-E interface.

  2. First, I'd clean the dust.

    And the 6850 will work at the same speed PCI-E 2.0 x8. So there won't be a performance difference.
  3. So if you take a look at the picture you took, check the sticker on the back of the card where it says 2400 and you will then see "AGP" :pt1cable:
  4. jimpz said:
    I *THINK* your graphics card has an AGB, NOT a PCI-E interface.
    It definetly is not an PCI-E interface.


    Ah, you're right! The store I bought it from says it's PCI-Ex16, but it says AGP (which I didn't know what was until now) on the card, and I remember the Box the card arrived in said it as well, and sapphire's websites says it too.
    That explains it.

    Thanks alot for your feedback!

    Yes, hillarious, I need a dust-cleaner :kaola:
    It hasn't been used in 4 years, so..

    And this video card is designed for 2.1 x16, not x8, so how does that add up? (I don't understand)

    Yeah, I didn't even know what AGP was though, but thanks for your comment ;)
  5. Hehe no problemo. The 2400(and 2600, 36xx) came out during the transition period from AGP to PCIe. So the card could have been either.
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