AGP Drive Strength

[rylan]

I'm looking for your opinion/experience as to what is a good setting for AGP Drive Strength for a G400MAX. It sefaults to "auto" but I'd rather not have it set to that, since I've heard the bios doesn't compensate correctly sometimes (especially when overclcoking the fsb).

[paulcs]

I can give you suggested settings for the GeForce series for the VIA Apollo Pro 133A chipset and the Radeon for Abit's KA7-100. The reason I know these are because of problems both boards have had with some VIA-based systems. I've never heard of a G400 having issues with the AGP driving values of VIA boards, although there were driver issues in the past. Are you having a problem?

In order to get the GeForce line to run properly with AGP 4X enabled, many users have had success with an AGP Driving Value of DA or EA. Of course, you'd have to Change the AGP Driving Control to Manual if you intend to deviate from the default setting.

Radeon users with Abit KA7 and KA7-100 motherboards have had good luck with an AGP Driving Value of 68 when they had problems booting into Windows or to achieve stability with AGP 2X enabled.

Given the GeForce and the G400 share many quirks (I wonder why. ), I'd experiment with the GeForce values. The Radeon issues are probably different. The symptoms are certainly more severe.

If I you aren't having a problem, I'd leave it where it is. If it ain't broke, don't fix it.

Paul
paulcs@flashcom.net

[This message has been edited by paulcs (edited 29 November 2000).]

[rylan]

I'm not really having problems at the moment. I just wanted a couple suggests and stuff to try since I'm going to be pushing my system. I have a KT133 based board (Athlon 800@1GHz).
What you said is pretty much what I wanted to know. Thanks

[kjliew]

The G400 chip itself has its own AGP compensation, while the G200 doesn't. Earlier AGP chipsets don't provide drive strength compensation at all, such as VIA MVP3. (Or maybe, those registers are not published in the specs.)

Not sure about NVidia/ATI graphics chips, I can never get hold of any of their chip specs.

[CannyOne]

Uh Oh! I sure wish I had seen this thread a little sooner. rylan you need to be very cautious when altering your AGP's drive strength. It can render your AGP slot unuseable!! I can verify that the DA and EA values won't mess things up with the G400MAX but I wouldn't recommend them, or any value other than "Auto". The issues with drive strength on KX/KT133 boards relates to AGP 4X. Unless the part # of your MAX ends with a "4A". The Matrox card won't be capable of 4X AGP. Besides this fact, AGP 4X simply chews up memory bandwidth and can lead to instability on KX/KT133 boards.

You don't mention which KT133 chipset board you have? But from experience I'd say that your attempts to push the FSB speed too far out of specification will not meet with success. Simply put, the EV6 bus doesn't take kindly to it. The result is that I would say "don't listen" to all issues that Nvidia and ATI owners are having. Initially you should use the "auto" setting and see if any issues arise.

BTW I'm running an 800 TB@1 GHz on a A7V with an Asus V7700 at the moment. So I am familiar with some of the issues. I will also be building another rig (Duron powered) that I intend to use my G400MAX in very soon. If you are having any real issues I'd be happy to collaborate with you on these settings. Drop me an email!

[This message has been edited by CannyOne (edited 02 December 2000).]

[rylan]

My motherboard is an Epox 8KTA2 (fairly new), and uses the 686B southbridge for ATA/100.

I've had pretty decent results with overclocking the fsb on this board. 110 is stable, and I can do 112+ if I keep the chipset cool, so I'm getting a blue orb as a chipset cooler and some tiny heatsinks for the clock generator and voltage regulators.
Seems like 116 is around the limit of what people have gotten with the EV6 bus (232 MHz effectively), but from what I've seen the A7V doesn't like to go much over 110 w/o extra cooling.

If you're into some serious overclcoking, head over to the forums at www.amdzone.com