An 8x AGP card in a 4x slot?

Question

I have an AK32 mainboard with a 4x AGP Graphics card slot. Will a AGP 8x graphics card work ok in this slot? What is the difference between an 8x and a 4x?

Answer 1

Hi there!
I have looked on the shuttle.com website, found your motherboard,
downloaded the manual, read the listed specifications, and can't
really give you a definitve answer.
Thank you so much for providing the model number of your unit !
The problem with saying " YES " you can put in ANY 8x AGP card is that your manual does not clearly state the specification to the keys and voltages that are used on its version of the 4X AGP, and you
did not provide the information on EXACTLY which 8X AGP you are going to install.

There is a simple explanation of the " standard" AGP slots, voltages, keys, and compatabilities here:

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website link http://www.interfacebus.com/Design_Connector_AGP.html

AGP Bus Description
AGP [Accelerated Graphics Port] is a Point-to-Point [Chip-to-Chip] bus using 1.5 Volt or 3.3V signaling. The main use of the AGP bus is as a Local Video bus in IBM compatible Personal Computers [PCs]. The AGP interface bus is based on the PCI [Peripheral Component Interface] spec, using the PCI specification as an operational baseline. The AGP specification adds 20 additional signals not included in the PCI bus. The AGP specification defines the Protocol, Electrical and Mechanical aspects of the bus. Refer to this page for a comparison of Video bus through-put for different expansion buses.

The Mechanical definitions include a connector and AGP Board [Add-in card]. The Card sizes and 1.5v and 3.3v connectors are also defined within the spec. There are five connectors defined: AGP 3.3v, AGP 1.5v, AGP Universal, AGP Pro Universal, AGP Pro 3.3v, and AGP Pro 1.5v. PCI and AGP boards are not mechanically interchangeable.
The AGP 1.0 specification defined 1x and 2x speeds with the 3.3v keyed connector.
The AGP 2.0 specification defined 1x, 2x and 4x speeds with the 3.3v, or 1.5v keyed connector or a 'Universal' connector which supported both card types.
The AGP Pro specification defined 1x, 2x and 4x speeds with the 3.3v, or 1.5v keyed connector or a 'Universal' connector which supported both card types.
The AGP 3.0 specification defined 1x, 2x, 4x and 8x speeds with the 1.5v keyed connector or a 1.5v AGP Universal / Pro connector.
Each up-grade is a supper-set of the 1x mode, so 4x will also support the 1x speed. The base clock rate is 66MHz, but to achieve to 2x, 4x, and 8x speeds the clock is doubled each time. AGP uses both edges of the clock to transfer data.

AGP (1x): 66MHz clock, 8 bytes/clock, Bandwidth: 266MB/s [3.3V or 1.5V signal swing]
AGP 2x: 133MHz clock, 8 bytes/clock, Bandwidth: 533MB/s [3.3V or 1.5V signal swing]
AGP 4x: 266MHz clock, 16 bytes/clock, Bandwidth: 1066MB/s [1.5V signal swing]
AGP 8x: 533MHz clock, 32 bytes/clock, Bandwidth: 2.1GB/s [0.8V signal swing], still uses 1.5 volt motherboard power

The AGP data bus may be 8, 16, 24, 32, or 64 bits. Due to timing requirements the maximum bus length is 9". The trace impedance is specified as 65 ohms +/- 15 ohms (no termination resistor is specified). For the 8x speed the bus requires a parallel termination or 50 ohms. Some lines may require a Pull-Up Resistor to insure the lines come out of reset in the proper state. The AGP Interface is optimized for FR4 PCB designs. Both 4 layer and 6 layer PCBs have been studied.

AGP 2.0 pin out, 2 rows of 66 finger [pins]. The Pin Outs for AGP 3.0 specification differ from the AGP 2.0 Standard.
Not all AGP cards will work in all AGP slots. Use the table below, to determine if an AGP board will function in a particular motherboard. The AGP pinout list is provided lower down the page.


AGP Card / Motherboard Functionality
AGP 2.0 Cards AGP 3.0 Cards
MotherBoard 3.3 Connector 1.5 Conn. Universal Conn. Univ. AGP3.0 Conn AGP3.3 Conn
AGP 3.3 Works Keyed Wrong Works Keyed Wrong Keyed Wrong
AGP 1.5 Keyed Wrong Works Works Works No Function
AGP Universal Works Works Works Works No Function
Univ. AGP 3.0 Keyed Wrong Works Works Works Works
AGP3.0 Keyed Wrong No Function No Function Works Works

AGP 3.0 boards only work off of a 1.5 volt connectors / Mother Boards
There are three different key configurations for AGP cards: 3.3v keyed [1x, 2x], 1.5v keyed [4x, 8x], 1.5v universal keyed [1x, 2x, 4x].

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You will have to copy and paste the text to try to read the table above, since the encoding on their website, and ANSWERS does
not match and the TABS and spaces are wrong..

BUT, as you can see from the text descriptions, " ANY " 8x AGP card will not fit in " ANY " 4 X slot since there are at least 3 different keying arrangements, and your motherboard manufacturer does not list the keys - if you carefully look at the keys and cross reference, the pin numbers you could tell.

To make things worse, there are a dozen non- standard so-called " AGP " cards and motherboard combos shipped from Taiwan etc. that dont match anything, except each other.

The bottom line is that you really must do your homework and be aware that whatever you buy to put in MAY NOT be guaranteed to work.

The 8X " standard" is supposed to work backwards, and if all the motherboard manufacturers and AGP card manufacturers actually followed the specifications to the letter, they would.

THEN... there is the issue of purchasing an expensive new 8X card that will only give you 10% improvement at best, on a motherboard that lists the highest CPU speed in the manual at
1.3 GIG Hz. You may want to consider the options of getting more ram, getting a faster harddrive, removing background programs in Windows that are wasting your CPU speed ( typically Start/ Run / msconfig ). This way, the new harddrive at a higher rpm and more cache could be used on your next machine. It is unlikely that the ram would be useable on a new platform, so look on ebay for cheap ram - everyone is dumping it at very good proces ( ecxept in the retail outlets ).

A recent ANSWER had a good response to this question which I will repeat here:

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WellTraveledprog

You wouldn't see a 2X performance increase for the 8X over the 4X for any game, movie,etc. That's because the only thing that's twice as fast is the data transfer rate from main memory to the graphics card, not the whole system. And even if the data can *get* to the graphics card twice as fast, there's no guarantee the graphics card can use it twice as fast :)

In general, for graphics-heavy applications like a 3D game at high res, I'd expect maybe a 10% speed increase for an 8X over 4X AGP card. Some particular things would run much faster than 10% faster, and you might be able to run at a higher resolution while keeping an acceptable framerate...but the difference really won't be that big. You'd see a much better speed increase going to a PCI-Express slot than you would between 4x and 8x AGP.
Hope that helps :)
Source(s):

former CTO of a video game company, 20 years developing video game hardware/software

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Hope that this helps ! I know it looks confusing - because it is - anyone who just sayes
" NO " you cant, probably had an 8X that was keyed differently with the wrong voltage keys, and anyone who sayes " YES " probably had a UNIVERSAL 8X AGP card put in a UNIVERSAL keyed AGP 4X slot, and had no problems...
If only life were that simple...
If anyone worked in a shop where they assemble 25 computers a day, and upgrade another 15 a day, they would KNOW that there are exceptions to every rule !

Shop around and do your homework !
Consider the options, consider the prices... you are on the web, and it is a powerful tool to get information from many sources.

Good luck

robin

Answer 2

I love it when people answer and have no idea what they are talking about, yes it will work but it will be slower. The rule on AGP is that they are always backwards compatible one step, meaning an 8 will go in a 4 and a 4 will go in a 2, etc.

Answer 3

relies upon on your BIOS. often particular. Occaisionally AGP slots would be proprietary, yet maximum mboards will step down the AGP card to the applications of the on-board BIOS. pay interest to voltage required via your card and make certain your mboard can assist you in direction of the mandatory slot.

Answer 4

It should fit and work at 4x speeds. The difference is the information bandwidth.

Answer 5

yes it will work but only at 4x .... the diference is the "speed" at which it runs like on a cd rom 4x is slower than 8x ....... hope that helps

Answer 6

my friend, it will not work. The slots are different. The difference between the two is mainly the speed.

Answer 7

it will work but only at the slowest speed (4X)