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Reversed AGP slots ? Is this even possible ?!

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First post, by Elia1995

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I just found an AGP card which seems to have the AGP contacts reversed than any other AGP graphics card I've owned so far... I'm serious, it's not a PCI-e card, it's AGP, but it's backwards 😳

The model on it is an S3 VGA Trio, I tried to plug it in the Asus P4P800, but it doesn't fit, it's backwards !!! The longer part is opposed to the smaller part... I can fit any AGP card that has the pins divided into "3 parts" and my nVidia 7300GT which has it into 2 parts like this one... but reversed.

I have no idea how to fit this card... it's AGP for sure, PCI-e cards have the pins quite "smaller" and much longer, the size compared side-by-side to my 7300GT is the exact same, only reversed... WTF ?

It looks like this: s-l300.jpg

and the only AGP working motherboard I currently have is this one: f7003545049e4a6aa69cbf739e01c156.png

Notice how the shorter peg is on the other side than the longer peg in the AGP card slot...

Currently assembled vintage computers I own: 11

Most important ones:
A "modded" Olivetti M4 434 S (currently broken).
An Epson El Plus 386DX running MS-DOS 6.22 (currently broken).
Celeron Coppermine 1.10GHz on an M754LMRTP motherboard

Reply 1 of 21, by jmannik

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That card is an AGP 1x or 2x 3.3v card, your montherboard is a 1.5v AGP 4x or 8x slot. It's not backwards, its keyed so you wont kill it by plugging it into an unsupported agp slot.

Dos: AMD 386 DX40 | 8MB RAM | SB Vibra 16
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Reply 2 of 21, by Errius

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That's just an oldschool 3.3V AGP card. It'll only go into oldschool 1990s mobos, or else mobos with Universal AGP slots.

ETA: this reminds me, is it safe to plug hi-end PCI graphics cards into 1990s era PCI slots? I tried doing this a while ago (440BX and GeForce 8400 GS in Windows XP) and weird things happened, including drive corruption. Problems disappeared when I removed the card. What might have been going on?

Last edited by Errius on 2016-06-26, 12:54. Edited 2 times in total.

Is this too much voodoo?

Reply 3 of 21, by stamasd

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AGP compatibility for sticklers

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 4 of 21, by Elia1995

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Awww... so that card is useless, ok...

(well, on the other hand, I believe that the 7300GT is much more powerful anyway, it was just for retro's sake)

Thanks guys 😁

Currently assembled vintage computers I own: 11

Most important ones:
A "modded" Olivetti M4 434 S (currently broken).
An Epson El Plus 386DX running MS-DOS 6.22 (currently broken).
Celeron Coppermine 1.10GHz on an M754LMRTP motherboard

Reply 5 of 21, by Jonas-fr

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Errius wrote:

That's just an oldschool 3.3V AGP card. It'll only go into oldschool 1990s mobos, or else mobos with Universal AGP slots.

ETA: this reminds me, is it safe to plug hi-end PCI graphics cards into 1990s era PCI slots? I tried doing this a while ago (440BX and GeForce 8400 GS in Windows XP) and weird things happened, including drive corruption. Problems disappeared when I removed the card. What might have been going on?

I'm eagerly wiating for an answer since I've got a Radeon HD5450 PCI Edition (512MB) and it doesn't work on old (PII era mobo I have). I only hope that I didn't killed it since I read somewhere that PCI 3.0 cards are 3.3V and first PCI slots were higher (like 5V) :s

Reply 6 of 21, by nforce4max

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Entertaining really /popcorn

3.3v and 1.5v cards are easy to tell apart and the same for most slots, when in doubt always google.

On a far away planet reading your posts in the year 10,191.

Reply 7 of 21, by shamino

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Jonas-fr wrote:
Errius wrote:

ETA: this reminds me, is it safe to plug hi-end PCI graphics cards into 1990s era PCI slots? I tried doing this a while ago (440BX and GeForce 8400 GS in Windows XP) and weird things happened, including drive corruption. Problems disappeared when I removed the card. What might have been going on?

I'm eagerly wiating for an answer since I've got a Radeon HD5450 PCI Edition (512MB) and it doesn't work on old (PII era mobo I have). I only hope that I didn't killed it since I read somewhere that PCI 3.0 cards are 3.3V and first PCI slots were higher (like 5V) :s

The later spec revisions did address the subject of 3.3v in some way, maybe even made it mandatory (not sure) to support that voltage, but those cards generally also work with 5v. They had to, 5v was way too common to drop support for it. I assume the later PCI specs were trying to encourage a transition to 3.3v by getting newer cards to support it, but the typical PC motherboard still didn't.

3.3v and 5v PCI cards and slots are keyed differently, so if it fit the 5v slot then it should be safe there (similar to how AGP was handled). Most later PCI cards are keyed to fit both and will tolerate either type of slot.
There are a few generations of the PCI spec and some of the differences are probably why the card didn't work on your P2, but I don't think it damaged anything electrically.

3.3v PCI slots are uncommon, they really just showed up in servers and workstations. They were never embraced as a standard for desktop motherboards (despite years of moaning about the performance limits of the older standard). A card like that HD5450 was probably aimed at people with low cost Dell/etc P4 desktops that only had PCI slots, but were still a viable market for graphics upgrades. Those are still 5v slots. They adhere to a later spec, but they're 5v.

The only cards that are likely to *require* a 3.3v slot are cards that were intended for servers.

I wonder if some of these late PCI graphics cards will run at 66MHz or more if installed in a capable 3.3v slot. I always wanted to try that with a couple cards that I have, but the system I attempted it on was too slow to be able to tell if the higher clock was actually in effect.

Reply 8 of 21, by Carlos S. M.

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Like other people said, there are different AGP specs, your S3 Trio 3D/2X is an AGP 1.0 Card (1x/2x, 3.3 volt only) when your ASUS P4P800 Deluxe (Nice board, i have the P4P800-E Deluxe which is an upgraded version of the P4P800 Deluxe) has an AGP 3.0 slot (4x/8x, 1.5/0.8 volt only). There are motherboards with universal AGP slots (no keys on the slot) which supports both 3.3 and 1.5/0.8 volt cards, but are generally limited to 1x/2x/4x sppeds, Universal AGP mobos were only common on the Pentium III/Athlon era, although there are some Pentium 4 and Athlon XP mobos with the universal slot.

Look at these links:
http://www.playtool.com/pages/agpcompat/agp.html
https://en.wikipedia.org/wiki/Accelerated_Graphics_Port

https://en.wikipedia.org/wiki/Accelerated_Gra … _Pro_Keying.svg

What is your biggest Pentium 4 Collection?
Socket 423/478 Motherboards with Universal AGP Slot
Socket 478 Motherboards with PCI-E Slots
LGA 775 Motherboards with AGP Slots
Experiences and thoughts with Socket 423 systems

Reply 9 of 21, by candle_86

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Errius wrote:

That's just an oldschool 3.3V AGP card. It'll only go into oldschool 1990s mobos, or else mobos with Universal AGP slots.

ETA: this reminds me, is it safe to plug hi-end PCI graphics cards into 1990s era PCI slots? I tried doing this a while ago (440BX and GeForce 8400 GS in Windows XP) and weird things happened, including drive corruption. Problems disappeared when I removed the card. What might have been going on?

I dunno I tested a 440bx board with an HD3450 PCIe and it worked great

Reply 10 of 21, by stamasd

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440BX boards don't have PCIe slots.
This thread gets better and better.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 11 of 21, by Carlos S. M.

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stamasd wrote:

440BX boards don't have PCIe slots.
This thread gets better and better.

Maybe he's using a PCI-E to PCI adapter. These kind of adapters exists

What is your biggest Pentium 4 Collection?
Socket 423/478 Motherboards with Universal AGP Slot
Socket 478 Motherboards with PCI-E Slots
LGA 775 Motherboards with AGP Slots
Experiences and thoughts with Socket 423 systems

Reply 12 of 21, by stamasd

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PCIe to PCI adapters do exist. PCI to PCIe, not so much. To plug a PCIe card into a BX board you'd need one of the latter.

(yes there are bridge chips but I've never seen discrete adapters made with them)

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 13 of 21, by Errius

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I remember the time I discovered this AGP issue, trying to plug my favorite old video capture card (Marvel G200) into my new P4 mobo. It wouldn't go. I wasn't happy. I had to get a new card to go with the new board.

Is this too much voodoo?

Reply 14 of 21, by darry

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stamasd wrote:

PCIe to PCI adapters do exist. PCI to PCIe, not so much. To plug a PCIe card into a BX board you'd need one of the latter.

(yes there are bridge chips but I've never seen discrete adapters made with them)

Well there is this . I wonder if it would work in a 33Mhz PCI slot :
http://www.chinaseniorsupplier.com/Computer_H … apter_Card.html

The bridge chip is by PLX Technology according to this photo :
http://img.diytrade.com/seimg/2161273/4036195 … I-E_Adapter.jpg

Reply 15 of 21, by candle_86

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stamasd wrote:

440BX boards don't have PCIe slots.
This thread gets better and better.

sorry PCI, im so used to tryping PCIe these days, my bad but a PCI 3450 worked on my SOYO board

Reply 16 of 21, by nforce4max

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stamasd wrote:

440BX boards don't have PCIe slots.
This thread gets better and better.

IKR, eating more popcorn...

On a far away planet reading your posts in the year 10,191.

Reply 17 of 21, by shamino

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I remember when I upgraded from an ISA graphics card to PCI, I was convinced the dumb manufacturer had gotten the bracket backwards.

But on that note, I am still annoyed that when Express slots came out, they didn't take advantage of the opportunity to flip the cards back over again. They're still upside down, damnit.

Reply 18 of 21, by Elia1995

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Yeah, it's quite disappointing to not be able to enjoy the cool and fancy coolers that the new GPUs come with 🙁

Currently assembled vintage computers I own: 11

Most important ones:
A "modded" Olivetti M4 434 S (currently broken).
An Epson El Plus 386DX running MS-DOS 6.22 (currently broken).
Celeron Coppermine 1.10GHz on an M754LMRTP motherboard

Reply 19 of 21, by 386_junkie

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nforce4max wrote:
stamasd wrote:

440BX boards don't have PCIe slots.
This thread gets better and better.

IKR, eating more popcorn...

🤣 ... this is beyond even me.

I haven't really got past VESA bus. So much so that now most projects i'm working on are EISA bus... going backwards!

Compaq Systempro; EISA Dual 386 ¦ Compaq Junkiepro; EISA Dual 386 ¦ ALR Powerpro; EISA Dual 386

EISA Graphic Cards ¦ EISA Graphic Card Benchmarks