HOW TO SMOKE YOUR AGP CARD

[Roy]

As nearly as I can tell, my Viper 330AGP died because I overclocked a mobo that did not provide a selection for AGP speed.

Further investigation suggests that most boards do not offer this protection. Abit lets you set the AGP:FSB ratio to 2:3 or 1:1.

So what is this all about? When AGP came on the scene with "2x" support, we were led to believe this meant two times the PCI/IDE speed of 33MHz. In a way this is correct, because on the 66MHz FSB boards, the AGP speed is 66. BUT ~ it is NOT accomplished by doubling the PCI/IDE speed, which would have been the best method. Instead, the FSB clock is used directly. Abit's 2:3 recognized this and allowed correct AGP speed with 100MHz FSB and protected the card when FSB was raised.

The first generation AGP cards were tolerant of 100, even though 66 was the design point. That's why mine died when I ran it at something higher. The new generation of cards offers "4x" support by way of a jumper. 4x33=133MHz, with tolerance above 150.

So keep all this in mind when you put your hotrod together. If you really want to play it safe, use a PCI graphics card. The PCI/IDE speeds are better managed on most boards. Or go for a card that supports 4x.

[This message has been edited by Roy (edited 10-02-99).]

[Mntsnow]

Roy,

I do feel for you as I too lost my AGP card last night! I am now in the process of trying to decide if I want another AGP card (to get the benifts of AGP archatecture) or to go with a PCI card for the safer O/C. What do you recommend for a good PCI card (I run a 17" monitor at 1024x768 and 24bit or higher color) I lost a Diamond speedstar A70 8meg AGP. /forum/frown.gif

Mntsnow

[Roy]

I'm more into overclocking than gaming, but I do value high quality graphics. Right now I'm using a $25 Trident AGP card. It's just fine at 1024x768 32bit (non moving graphics). Keep in mind this is on a slightly overclocked Abit BX6 set for 2:3.

If you can afford it, the AGP with 4x support is the best choice. You'll have to do some research to decide which controller chip you prefer.

[AuraEdge]

Roy,

When i run sandra, it reports that my AGP is running 67(66.6) x 2 = 134Mhz. You can check this out under mainboard properties

The AGPx2 is the FSBx(AGP multiplier)x2 and when AGPx4 is out it will be 266mhz for the AGP bus at default rates.

For instance on a normal katmai P3, it would be 100 x 2/3 x 2 = 133AGP bus.

this is as far as I understand it.

[Mntsnow]

well I think I am going to get another AGP card. I'm thinking about the Vodoo3 3000 as it is good step up from my Diamond speedstar and has been getting some good reveiws. I dont think I will be pushing my O/C quite so much anymore (C333 rock solid at 516 2.4v) (I lost the card trying to hit 560 /forum/smile.gif )

Mntsnow

[pickel]

Just making an observation.....
Thirty something years ago, We all had some kind of hot rod. Swapped carbs, rear ends, cams with same results. Once a while things came apart and we'd go back and try some thing different. I got my little AMD300 to 350 thanks to guys like you. It's good to see that old American spirit, just now with a different toy. When I got this computer., I has no idea folks were hoppin'em up. It feels good to be in the kind of company I grew up
with. Over Clockers KEEP ON TRUCKIN'!!!!!!!!

The Pickel

[chad174]

hey mntsnow, weve got the same chip, and i damaged my v550 trying for 560, did you get there stable??mine freezes like 2 seconds after i set it to 560 in softfsb, got my peltier and stuff..

[CMonster]

I always wondered about this: if the PCI bus can implement 64bit and the AGP is only 32 bit wouldn't it be possible for a PCI card to keep up with an AGP card if the implementation and PCI card was 64bit, even though the PCI bus is so much slower?

Anyway, I have a couple of machines with Nvidia 128 based 8MB PCI cards, and one with an ATI expert PCI 8MB, and I am still quite impressed with the performance from these three. Of course it's not as good as my 16MB TNT /AGP.

On the brighter note: Fry's has got the Athlon and mother boards - and a build it yourself bare bones is about $600 with the 550mhz /forum/smile.gif I think a nice TNT2 will go just fine with that! /forum/biggrin.gif ..soon ...soon

[Mntsnow]

Chad,

No my slot 1 333celery chip just wont do 560 with whatever I tried (pelts, extra fans h*ll I even bought dry Ice to ice down the chip and still no go. So I'm just going to call it quits at 516 and live with it /forum/biggrin.gif (until I can convince the wife that I need a PIII /forum/smile.gif ) That way I wont burn up my NEW VOODOO3 3000! This card is AWEWSOME! I'm not a big gamer but I got it on sale and since I needed a card badly, I bought it and am glad I did!

Mntsnow

[ufo]

I dont know what the hell you guys are talking about. If you remember TNT2's are suposed to do agp 4x but yet lots of them have problems at 89 bus. Your on crack if you think that the tnt 2 can do 133 bus. I really dont think that tnt 2 can support agp 4x yet. I bet there will be some patch or something to fix it but I knwo for a fact that if some cards cant even handle 89 how is it going to do at 133??!

[Joel Kleppinger]

The confusion is stemming from an understanding of AGP 1x, 2x, and 4x. NONE of these actually denotes actual AGP bus speeds, but rather memory transfer rates.

1x = 256MB/s
2x = 512MB/s
4x = ~1 GB/s

1x AGP runs at 66MHz FSB, as does 2x and 4x. It's just that the protocols are "tweaked" to push data along at double the rate.

[Bleeding Edge]

As Roy stated, the base (or core) of the AGP Data Clock is 66MHz. But it can also can be 133MHz, according to the AGP Standards.

The Data Transmit Clock (sideband speed) which AuraEdge stated is correct. At 2x the clock is 133MHz. At 4x it is 266MHz.

The specification for this architecture calls for the voltage controlled oscillator (VCO. This part is getting over my head...) to be doubled if need be, 266MHz for 2X or 532MHz for 4X.

The data transfer rates Joel refers to are correct also.

More info at: http://www.intel.com/technology/agp/

http://www.agpforum.org/

[Roy]

My reason for starting this thread was to elicit knowledgeable answers about the nature of AGP. I'm learning quite a lot. Thanks.

Keep 'em coming. /forum/smile.gif