AGP x2/x4/x8 compatability

[shrimps]

Ive said Id sort out an old machine for a family member and I was thinking about finding an old graphics card to put in it. Please dont anyone advise me to buy a new motherboard, go quadcore, or insist I need SLI. All I want is to get a bit more life out of a tired machine.

Its an HP and I had a quick look at the serial number on their website for the specifications. It says that it has an AGPx4 slot if I remember correctly, I did check quite a while ago. As AGPx4 cards seem to be incredibly hard to find, does that mean that I can put a x8 card in and just get half the bandwidth out of it or something along those lines, or are they incompatible technologies? Cheers for any help.

[digit]

That should work in theory. In reality some AGP 8x cards won't work in a 4x slot due to using the extra voltage that the AGP 8x specification provides. For example a 6800LE works fine in my computer and yet won't work at all in my brothers computer or my mums computer which both have agp 4x. I'd have a look around for a cheap geforce 4 or a radeon 8500 to 9000 series card to be on the safe side

[shrimps]

Yeah I just found this playtool.com/pages/agpcompat/agp.html#agp33vmotherboard (grr cant use url tags), the PC was definately due for a new standard... Im just a little concerned by the section about some motherboards, which only support x4, allowing you to use x8 cards at the wrong voltage and destroying them. Ill cancel that order for a 7800GS 512MB DDR3 AGP then

Just one thought, do cards which are listed as x4/x8 mean that they are fully backwards compatible to x4?

[digit]

Well it could well work, but I doubt it would. It doesnt list the 7800GS as working. However there is an agp 4x version of the 7800 vanilla lucking about, as a google indicated, but hell knows where you would get it. To be honest though unless the processor is up to much such a card would go to waste due to not having enough processor juice thrown at it as it were I hope someone else posts in case I have got it completly wrong

[SHare]

I was running a 6600 in an old 4x AGP board and it was fine, even handled most games reasonably so it might be worth looking out for one of those.

[Agent]

Yeah I just found this playtool.com/pages/agpcompat/agp.html#agp33vmotherboard (grr cant use url tags), the PC was definately due for a new standard... Im just a little concerned by the section about some motherboards, which only support x4, allowing you to use x8 cards at the wrong voltage and destroying them. Ill cancel that order for a 7800GS 512MB DDR3 AGP then

Just one thought, do cards which are listed as x4/x8 mean that they are fully backwards compatible to x4?

The voltage thing was rare when it was top end technology. Very few cards / boards were effected by it. Some of the ones that were had BIOS level voltage selection IIRC.
Dont get me wrong, the card could be fried if used in a board that didn't support the correct one, but its a problem that is commonly over exaggerated

Your best bet is to take a look at the slot on the board and try and match it with one of the ones here and read this

More to the point, this bit -

There are three versions of the AGP physical interface, for 3.3 V and 1.5 V cards respectively. The 1.5 V version has a key further away from the external connector, while the 3.3 V version is the opposite. But some poorly designed older 3.3 V cards incorrectly have the 1.5 V key, which may result in burnt mainboard if installed in a AGP 4X/8X slot. The third physical interface is universal, allowing installation in both 1.5 V and 3.3 V motherboards

Well it could well work, but I doubt it would. It doesnt list the 7800GS as working. However there is an agp 4x version of the 7800 vanilla lucking about, as a google indicated, but hell knows where you would get it. To be honest though unless the processor is up to much such a card would go to waste due to not having enough processor juice thrown at it as it were I hope someone else posts in case I have got it completly wrong

There is no 4x only AGP card of the 7800 series. Infact, the last series to have a 4x AGP port only was the 4x00 range off the top of my head. They were phased to 4x/8x, with the 5xxx (FX) range having 4x/8x AGP only.

Provided the voltage wasn't an issue like said above - it would work fine. AGP is backwards compatible (although not forwards )

You are totally right on the CPU front though. This card would be a total waste in a system that old, unless its a higher spec than normal (being a HP though, thats probably not true sadly )

What do you currently have in it? You would be very surprised how powerful the 6xxx range were - they can be had on Ebay for cheap and would be much better suited to a machine of that age

[shrimps]

Dont worry I wasnt being serious about sticking an expensive graphics card in this machine. There are an awful lot of 6000 series GeForces knocking about on ebay, by the sounds of it they should be alright. Just to ask again (apologies, I know its already been touched on), would a card which is listed as being x4/x8 mean its without a doubt compatible with both? Have a look at the following for example scan.co.uk/Products/ProductInfo.asp?WebProductID=283839 (2 posts to go before i can use url tags)

Im sleeping easy about frying components now too...

Thanks for the quick replies, really appreciate it.

[digit]

Agent: http://www.barefeats.com/mutant3b.html Hmm, I was only going purely by that link, perhaps they mean a 4x/8x card which would make sense I guess!

Shrimps: I would assume so, should work fine. Perhaps the voltage issue isnt a problem them going by what agent has been saying perhaps its just me having some older mobo's lying around at home that suffers from the voltage issue, could have a look to see about the voltages in bios actually so my brother can scrap his frankly rather awful geforce fx 5600

[Agent]

Dont worry I wasnt being serious about sticking an expensive graphics card in this machine. There are an awful lot of 6000 series GeForces knocking about on ebay, by the sounds of it they should be alright. Just to ask again (apologies, I know its already been touched on), would a card which is listed as being x4/x8 mean its without a doubt compatible with both? Have a look at the following for example scan.co.uk/Products/ProductInfo.asp?WebProductID=283839 (2 posts to go before i can use url tags)

Im sleeping easy about frying components now too...

Thanks for the quick replies, really appreciate it.

Yes, The AGP standard specifically requires that backwards compatibility is part of a cards feature
The only issue that ever happened was the voltage thing, covered above. While this was rare, it was always worth checking

Agent: http://www.barefeats.com/mutant3b.html Hmm, I was only going purely by that link, perhaps they mean a 4x/8x card which would make sense I guess!

Which bit are you reading exactly?
For a start, that's going on about mac's, which are not directly comparable to PC's. Although its not too bad these days, Apple have a habit of locking hardware down to what they want to allow you to use.

[Mithrandir]

You should have a look at ebay. Something like Geforce 3 Ti series, possibly along the lines of 4200 as well.

My mobo can only support up to AGP 4x only (not in my sig but my older system with Gigabyte 71XE and Athloon 900mhz )