From what I understand (though I’m remembering back a long time!) an AGP 3.0 device (so 8x compatible) must be able to tolerate 1.5v signalling from the motherboard. It won’t necessarily work (though I’d imagine it will, I’ve never come across an 8x card that won’t work in a 4x board), but it shouldn’t cause any damage to either component.

I'm not sure there were any 0.8 volt AGP 8x cards anyway, I thought they were all 1.5v.

Not so sure that Nvidia bothered to implement 0.8v signaling. More likely that all their cards work with 1.5v, because even GeForce 6800 and HSI bridge retained 3.3v signal compatibility.

And no, you can't fry video card with low voltag, it just will refuse to work. But all AGP 8x boards are compatible with AGP 4x cards anyway.

The Serpent Rider wrote on 2022-12-27, 09:51:

And no, you can't fry video card with low voltag, it just will refuse to work. But all AGP 8x boards are compatible with AGP 4x cards anyway.

I meant, the card is AGP 8x, but the mainboard provides only 1.5V. So it's actually an over-voltage. (AGP 8x is 0.8V, right?)

deksar wrote on 2022-12-27, 16:57:

The Serpent Rider wrote on 2022-12-27, 09:51:

And no, you can't fry video card with low voltag, it just will refuse to work. But all AGP 8x boards are compatible with AGP 4x cards anyway.

I meant, the card is AGP 8x, but the mainboard provides only 1.5V. So it's actually an over-voltage. (AGP 8x is 0.8V, right?)

It should still be fine. That card is “Universal AGP 3.0”, which means it’ll be happy regardless of signalling voltage (including 3.3v). It will likely be limited to 4x operation though.

Thanks for the replies, first of all.

The motherboard is AGP 8x, the card is AGP 8x, but it'll be limited to 4x operation? I'm really confused..

Why?

It’s not a given that it’ll be limited to 4x, just that’s how the standard is “supposed” to work. In reality, AGP was on it’s deathbed by 8x and few (if any?) manufacturers of both motherboards and add-in cards tended to implement them 100% standard.

Either way it’s going to work just fine, and even if it were 4x limited (which it might not be), you’d likely not notice anyway, which the reviews of the time showed more often than not. The rest of the system will become a bottleneck before the AGP BUS will.

paradigital wrote on 2022-12-28, 07:15:

In reality, AGP was on it’s deathbed by 8x and few (if any?) manufacturers of both motherboards and add-in cards tended to implement them 100% standard.

First AGP 8x video cards and chipsets were made in 2002, much earlier than PCIe bus standard was set in stone.

I think that 1.5v only warning more applies to 3.3v cards than it does to .8v