AGP 4X card in 2X slot?

Tanita

Junior Member
Oct 8, 2002
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All recent videocard models are AGP 4X compliant and the motherboard support only AGP 2X.
I understand that also the voltage is different: 3.3V for the AGP 2X and 1.5V for the AGP 4X.
Does this mean that I can burn a new AGP 4X videocard if I insert it in the AGP slot?
What options do I have?
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AnAndAustin

Platinum Member
Apr 15, 2002
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:eek: Well it does all get needlessly complex but essentially any AGP4x 1.5v card should run happily in AGP2x 3.3v mode. You need to check your AGP slot is AGP2.0 compliant (diff to AGP2x/4x which is the speed multiplier), otherwise your choice of cards is severely limited.
 

Peter

Elite Member
Oct 15, 1999
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AGP 2.0 compliance just means you have a higher power budget on that AGP slot. If it's AGP 1.0 only, then don't opt for the high performance cards, go for midrange cards instead. Low power fanless stuff like Radeon 9000 are a safe bet then.
 

alkemyst

No Lifer
Feb 13, 2001
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if you can do 2x you are set, so far no one really has proven 4x vs 2x is such an improvement.

Most cards are backwards compatible.

 

Tanita

Junior Member
Oct 8, 2002
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Guys,
I am talking about the voltage the motherboard is giving to the AGP slot.
From ATi specifications they are:
AGP v1.0(2X)= 3,3V
AGP v2.0(4X)= 1.5V
This means that is you put a 4X videocard (needs 1.5V) in a AGP v1.0 slot which gives 3.3V you can burn your videocard or your motherboard!???
 

hans007

Lifer
Feb 1, 2000
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i used a celeron 533 with a 440ex chipset (ancient 5 year old machine that used to be a 333 celeron) to test out geforce4 ti4600s. it seemed to run fine, so it should work.


i think some cards are made for 4x only motherboards, but most are made with the ability to use a 3.3v supply in 2x mode.
 

Peter

Elite Member
Oct 15, 1999
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Originally posted by: Tanita
Guys,
I am talking about the voltage the motherboard is giving to the AGP slot.
From ATi specifications they are:
AGP v1.0(2X)= 3,3V
AGP v2.0(4X)= 1.5V
This means that is you put a 4X videocard (needs 1.5V) in a AGP v1.0 slot which gives 3.3V you can burn your videocard or your motherboard!???
Supply voltage is ALWAYS 3.3V. Signalling voltage is 1.5V for 4x, and 3.3V for 2x/1x. Mind you, the vast majority of 4x cards are "universal", auto switching the signalling voltage to what the mainboard offers.

Visit ATi's FAQ pages for a rundown of what fits where, and how this is mechanically keyed so that only electrically compatible stuff can be plugged together.

http://mirror.ati.com/support/faq/agpchart.html

(scroll down to bottom of page)

regards, Peter
 

kylebisme

Diamond Member
Mar 25, 2000
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i have a freind with an amd750 chipset (agp x2) and a gefoce4 ti4600 that work fine together so that prety well discounts the possablty that a high power card will not work in a x2 slot.
 

Peter

Elite Member
Oct 15, 1999
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That's a different story. A 2x-only slot may still comply to the AGP specification 2.0, fulfilling the power requirements of current high performance cards. 4x is a mode that wasn't there before the AGP specification was revised to 2.0, but that doesn't imply it has to be there in 2.0-compliant boards.

regards, Peter
 

AnAndAustin

Platinum Member
Apr 15, 2002
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;) Rem there are 2 diff key notations for AGP slots, AGP1.0, AGP2.0 and AGP3.0 which are standard to do with voltage, power regulation etc and AGP1x AGP2x, AGP4x and AGP8x which are speed multipliers.

:eek: You can have an 2xAGP slot which is AGP2.0 compliant but it is very unlikely. You can have a well made more flexible AGP1.0 slot which will take AGP2.0 cards but again that is very unlikely. You can't (at least AFAIK) have an AGP1.0 compliant AGP slot which only runs at 2xAGP so if you have 4xAGP you also have at an AGP2.0 compliant slot.

AGP1.0 uses 3.3v signals with a 3.3v connector, it was the original AGP spec offering a dedicated bus to the gfx card offering better system RAM access and pipelining. Anything relatively modern is likely to be problematic in these slots esp if it has more than 16MB RAM, you may be better off considering a mobo upgrade or PCI gfx card. They were mostly AGP2x and fall back to AGP1x.
AGP2.0 uses 1.5v signals with a 1.5v connector, it handles voltage req and power regulation much better, it incorporates fast writes and usually comes in AGP4x form. It will fall back to AGP1x and AGP2x but only in UNIVERAL form will fall back to AGP1.0 operation.
AGP3.0 uses 0.8v signals but still uses a 1.5v connector, enhances a few other things and comes in AGP8x form which will fall back to AGP2.0 and AGP4x but no lower, although IIRC there is a UNIVERSAL AGP3.0 slot planned which will allow AGP2.0 operation and fall back to AGP1x if necessary.

;) The older cards like the Voodoo Banshee are AGP1.0. Most even remotely modern cards are AGP2.0 this includes GF2MX all the way up to GF4TI4600. There are very few 8xAGP cards and the perf boost over 4xAGP is VERY minimal, the cards are Rad9700, SiS Xabre and GF4-8X cards. I believe the lower spec Radeon AGP cards are about the gentlest AGP2.0 cards if you do have an AGP1.0 slot, but a mobo upgrade or PCI card may be better options. Gfx cards will fall back as much as possible but what you really need to watch out for are the old AGP1.0 AGP slots which are not wise to use with remotely modern AGP cards, there is a decent chance that the mobo and gfx card will be damaged even if it is not immediately evident. If you want an AGP slot to be most compatible with as many gfx cards as possible look out for a UNIVERSAL AGP slot.
 

Peter

Elite Member
Oct 15, 1999
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AnAndAustin, you're my hero. Many thanks for mixing things up AGAIN :(

AGP 1.0 defined 1x and 2x modes, at 3.3V.

AGP 2.0 _added_ 4x at 1.5V, but still has 1x and 2x the way they were. Additionally, the power budget for the card was raised substantially.

AGP 3.0 again added 8x, at 0.8V, again with everything else preserved.


Essentially you can have an AGP 3.0 compliant mainboard that supports 1x only. AGP 1.0 mainboards never support 4x or 8x modes. The vast majority of 4x/8x cards can fall back to 2x or even 1x though, auto-adjusting to the correct signalling voltage. The only thing to keep an eye on is power consumption ... AnAndAustin's 16-MByte rule is not adequate though. RAM adds little to the power consumption of a card, it's the graphics core itself. NVidia's and the Radeon 9700 are huge power mongers, while ATi's midrange cards as well as SiS's are well within AGP 1.0's power budget - even with 128 MBytes of RAM on.

btw, Voodoo cards aren't AGP at all. They're pure PCI devices that happen to be on the AGP bus.

regards, Peter
 

AnAndAustin

Platinum Member
Apr 15, 2002
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:eek: I've heard a few people swear they have AGP4x but are only AGP1.0 compliant (maybe a hybrid or else some wierd cheapo manu perhaps) and this is why I said, "AGP1.0 ... They were mostly AGP2x and fall back to AGP1x."

;) Other than that you seem to simply echo what I said. However you say, "AGP 3.0 again added 8x, at 0.8V, again with everything else preserved." Would this not imply that AGP3.0 slots can fall back to AGP2.0 and AGP1.0 modes with 3.3v and 1.5v signaling as that certainly isn't correct for most of the mobo AGP3.0/8x slots, you'd need a UNIVERSAL AGP3.0/8x slot to have that kind of ability.

:) AGP2.0 not only "handles voltage req and power regulation much better" but it also added support for memory sizes above 16MB, I did stress that 16MB was a 'be all and end all' thing but just a good guide. Quote, "AGP1.0 ... Anything relatively modern is likely to be problematic in these slots esp if it has more than 16MB RAM."

:eek: As for the Voodoo cards all actaully being PCI cards but with an AGP connection AFAIK this was only true for the Voodoo Banshee cards, the Voodoo5 certainly was a true AGP card surely!

:D It think we (you included Peter) need to be clear whether we are talking AGP mobo slots or AGP gfx cards!
 

Peter

Elite Member
Oct 15, 1999
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Originally posted by: AnAndAustin
:eek: I've heard a few people swear they have AGP4x but are only AGP1.0 compliant (maybe a hybrid or else some wierd cheapo manu perhaps) and this is why I said, "AGP1.0 ... They were mostly AGP2x and fall back to AGP1x."
Nope, that doesn't exist. 4x mode was introduced in AGP 2.0, no inbetweens, no "early adopters" that jumped the gun.

;) Other than that you seem to simply echo what I said. However you say, "AGP 3.0 again added 8x, at 0.8V, again with everything else preserved." Would this not imply that AGP3.0 slots can fall back to AGP2.0 and AGP1.0 modes with 3.3v and 1.5v signaling as that certainly isn't correct for most of the mobo AGP3.0/8x slots, you'd need a UNIVERSAL AGP3.0/8x slot to have that kind of ability.
See, that's what I mean. There is no such thing as an "AGP 2.0 mode". An AGP 3.0 mainboard that runs in 1x mode because the graphics card can't do any better still does that by AGP specification 3.0.
You keep linking specification revisions to mode support. This is the bit where you err. Any actual implementation that follows a certain AGP specification does NOT necessarily support everything this specification allows. E.g. AGP 2.0 compliant boards and chipsets are free to support any mode set out of 1x, 2x, 4x. Board design must then incorporate the right kind of slot hardware, with the appropriate key, so that only cards that are compatible with this particular implementation can be inserted.

:) AGP2.0 not only "handles voltage req and power regulation much better" but it also added support for memory sizes above 16MB, I did stress that 16MB was a 'be all and end all' thing but just a good guide. Quote, "AGP1.0 ... Anything relatively modern is likely to be problematic in these slots esp if it has more than 16MB RAM."
Again, no. No AGP specification has any mention of local memory size restrictions. In fact, since graphics card local memory isn't even connected to the AGP bus, this is rather obviously a completely unrelated topic. It's entirely up to the graphics chip's capabilities how much local RAM it can drive.

:eek: As for the Voodoo cards all actaully being PCI cards but with an AGP connection AFAIK this was only true for the Voodoo Banshee cards, the Voodoo5 certainly was a true AGP card surely!
No. None of the Voodoo card series are capable of anything AGP. This is a well known fact, and was even declared a policy at 3dfx.

:D It think we (you included Peter) need to be clear whether we are talking AGP mobo slots or AGP gfx cards!
 

AnAndAustin

Platinum Member
Apr 15, 2002
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:eek: I didn't mean to seem argumentative Peter, we both give our opinions and advice and that's fine.

QUOTE: "An AGP 3.0 mainboard that runs in 1x mode because the graphics card can't do any better still does that by AGP specification 3.0." AGP3.0 mobo slots only do 8x or 4x but only the UNIVERSAL AGP3.0 slots will fall back to 1x, IIRC AGP3.0 slots are keyed so you won't be able to put in an 1x or 2x AGP card.

QUOTE: "E.g. AGP 2.0 compliant boards and chipsets are free to support any mode set out of 1x, 2x, 4x." Again only UNIVERSAL AGP2.0 slots will allow the use of the older AGP1.0 type cards running at 3.3v and 1x/2x, the mobo should fall back to 1x and 2x but NOT AGP1.0/3.3v unless it is UNIVERSAL AGP2.0. AGP2.0 (non universal) are keyed in order to prevent the older gfx cards from being inserted.

QUOTE: "Again, no. No AGP specification has any mention of local memory size restrictions." It is something bore out in practice not written down on a spec sheet, and I haven't said it is 100% difinitive but simply a shortfall/oversight of the AGP1.0 spec and a good rough guide to what will work in the older AGP1.0 slots.

QUOTE: "No. None of the Voodoo card series are capable of anything AGP." Well even the Voodoo Banshee (Voodoo2 all-in-one AGP connector card) used the dedicated 66mhz AGP bus which in itself gave some benefits over PCI technology, it certainly lacked system RAM access for texture overspill but surely the later Voodoo cards supported higher 2x 4x operation and access to the system RAM. I know the Banshee was a little fudged interim solution by 3dfx as it was little more than a Voodoo2 with 2D ability and an AGP connector, and I realise the later Voodoo cards could have kept this clodged solution but surely they didn't?

;) I think you have to agree that the AGP specs are under-played/stated and overly complex, esp when it comes to precise compatability with the older stuff. So without getting in to needless and useless 'this is this' and 'that is that' we might as well give our advice on the original question. So back to the original question, my advice would be not to put a modern gfx card in an old AGP1.0 AGP slot (and if the mobo only supports 2xAGP mode then it seems it is AGP1.0), if you do a Radeon would be about the best to expect and a 64MB PCI Rad7500, Rad9000 or GF4MX would be a better idea anyway ... or simply upgrade the mobo as an even better idea. Plugging a modern gfx card in to an old AGP slot has been known to cause wierd problems and to damage the gfx card and/or mobo certainly in the long term, it makes more sense to go PCI or upgrade.
 

hans007

Lifer
Feb 1, 2000
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;) I think you have to agree that the AGP specs are under-played/stated and overly complex, esp when it comes to precise compatability with the older stuff. So without getting in to needless and useless 'this is this' and 'that is that' we might as well give our advice on the original question. So back to the original question, my advice would be not to put a modern gfx card in an old AGP1.0 AGP slot (and if the mobo only supports 2xAGP mode then it seems it is AGP1.0), if you do a Radeon would be about the best to expect and a 64MB PCI Rad7500, Rad9000 or GF4MX would be a better idea anyway ... or simply upgrade the mobo as an even better idea. Plugging a modern gfx card in to an old AGP slot has been known to cause wierd problems and to damage the gfx card and/or mobo certainly in the long term, it makes more sense to go PCI or upgrade.



i dunno if its a quality board, i wouldnt worry. i.e. an ASUS or something. i'm on my 2nd box,right now and the ti4600 is purring along nicely withthis celeron 533 on EX chipset asus board.
 

Peter

Elite Member
Oct 15, 1999
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*sigh* AnAndAustin, you just don't WANT to get it, do you? Now quit connecting AGP standards and transfer speed modes. This is plain incorrect.

AGP specifications 1.0, 2.0, 3.0 _include_ the slot keying rules. So a fictional AGP 3.0 compliant mainboard that only supports 1x mode is just as AGP 3.0 compliant as one that supports all of them, or only 4x/8x. Choosing the correct physical slot shape to match that capability is part of this specification. This is what prevents people from plugging incompatible stuff together. No need to

Voodoo chips, all of them, are 66 MHz capable PCI chips, no more, no less. They don't use AGP transfers at all, hence also don't use any of 1x, 2x, 4x transfer modes either.

Regarding your imagined memory size restriction on AGP 1.0 ... this is getting ridiculous. First you make that up, then get proved wrong, then claim it's an oversight in the specification. LOL. Who do you think you are?

Physical damage to the board or graphics card? Yeah right. The one and ONLY thing that matters is the card's power consumption. Everything else is managed by the slot and card keying that physically prevents plugging stuff together that doesn't belong together. Everything else is mythology.

All that said, it's pretty easy to choose a current card that fits an AGP 1.0 mainboard. Skip Radeon 9700 and any non-MX GeForce, watch for the card being keyed "universal" (two notches) and you're set.
 

AnAndAustin

Platinum Member
Apr 15, 2002
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:eek: Both AGP specs and AGP transfer rates are valid points here Peter ... look at the thread topic AND the original question (something you seem to have forgotten in your attempts to condemn me).

;) AGP2.0 UNIVERSAL doesn't use slot keying and allows and fully supports all the older cards as well as the newest cards too. AGP1.0 also doesn't use slot keying to prevent the newer cards being plugged in. AGP2.0 (non-UNIVERSAL) does use keying to prevent the older AGP1.0/3.3v cards from being plugged in. AGP3.0 only allows 8x and 4x operation using 1.5v, I'm not certain of what keying it uses or what cards are prevented but I'd be pretty sure it prevents older AGP1.0/3.3v cards while AGP2.0/1.5v cards will run in 4x mode. So you can plug a new AGP2.0/1.5v gfx card in to an AGP1.0 mobo slot but expect problems, even though the card should fall back to AGP2x and 3.3v mode there are other restricttions and problems LIKELY to rear their heads.

:D So all types of Voodoo gfx cards don't even use AGP1x ... I doubt that for technical reasons as AGP1x is little more than a dedicated 66mhz bus for the gfx card, the only function the Banshee didn't use was system memeory access for extra texture storage.

:eek: Regarding the 16MB restriction in AGP1.0, you really don't read what I said Peter despite me quoting it word for word. Lets try again, all I wrote was, "AGP1.0 ... Anything relatively modern is likely to be problematic in these slots esp if it has more than 16MB RAM." It is a ROUGH GUIDE as to what will work in these old AGP1.0 AGP slots hence the word ESP as in ESPECIALLY rather than DEFINITELY, I NEVER said it was a definitive guide.

;) Who do I think I am? Simply someone giving my experience and advice rather than you Peter who seem to like argueing and nit-picking rather than helping people.

:) I'd like to hear from more people who have used relatively modern gfx cards in older AGP1.0 AGP slots as easily found on S.Skt7 mobos, I know 100% that many people (not ALL) had the gfx card, mobo or both rendered useless even though it mostly worked in the short term. I wouldn't chance my money on buying a new gfx card for an AGP1.0 slot and I wouldn't suggest anybody do the same if I wasn't prepared to do it myself. You say YES Peter, I say NO, but we have the right to disagree on things you know.

;) I won't bother reading this thread now Peter, you simply fool yourself in to believing you're always right and anybody who doesn't agree 100% is wrong, it helps nobody and my time is better spent elsewhere ... go ahead rant away, it simply shows how sad and desperate you really are.
 

Peter

Elite Member
Oct 15, 1999
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Ah, the usual AnAndAustin approach ... claim, be proven wrong, argue, weasel around, and when running out of facts, deny what you originally said, insult, and leave.

Thanks.

Now that he's gone, back to providing information.

AGP 1.0 slots are keyed. The designers of the AGP specification anticipated that electrically incompatible changes would come. Just like PCI slots have been keyed right from the start.

AGP is all about the system RAM borrowing mechanism, no more no less. Chips that don't use it aren't AGP chips. Voodoo chips don't do that.

The only relevant thing to keep an eye on is card power consumption. That's what potentially grills boards. If you want to play safe, put something fanless in. E.g. Radeon 9000 w/ 128 MBytes of RAM is still within the power limits of the original AGP 1.0 specification.

regards, Peter
 

Peter

Elite Member
Oct 15, 1999
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Ah, the usual AnAndAustin approach ... claim, be proven wrong, argue, weasel around, and when running out of facts, deny what you originally said, insult, and leave.

Thanks.

Now that he's gone, back to providing information.

AGP 1.0 slots are keyed. The designers of the AGP specification anticipated that electrically incompatible changes would come. Just like PCI slots have been keyed right from the start.

AGP is all about the system RAM borrowing mechanism, no more no less. Chips that don't use it aren't AGP chips. Voodoo chips don't do that.

The only relevant thing to keep an eye on is card power consumption. That's what potentially grills boards. If you want to play safe, put something fanless in. E.g. Radeon 9000 w/ 128 MBytes of RAM is still within the power limits of the original AGP 1.0 specification.

regards, Peter
 

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