VOGONS


First post, by astigmatism

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I recently took out a Tyan Trinity S1598S motherboard with the VIA Apollo MVP3 chipset for some playing around. As is sometimes the case (I'm sure with some of you too), I began reading period reviews of the board and found this statement by Anandtech on the board's release in 1999 concerning the choice of the installed Northbridge:

We're going to give Tyan the benefit of the doubt and assume that the 598AT was just a honest mistake, and that the 598MVP chipset was supposed to be present on the S1598 but to be on the safe side, you should definitely check with your vendor to make sure you're getting the most up to date board. There is absolutely no reason you should have to settle for a chipset that has since been re-released after a few bugs were discovered. Shame on Tyan
https://www.anandtech.com/show/361/3

Despite that statement, Tyan did seem to install the VT82C598AT version of the Northbridge, my board has it. However, my research has not been able to uncover any official statements/press releases/recalls from VIA regarding this version having issues. I can of course verify that a replacement or alternative Northbridge was offered called the VT82C598MVP (which I have installed on an Epox board I own). I also found some great VOGONs threads about AGP voltage regulation issues on some MVP3 boards. Is it possible Anandtech assumed this was a chipset issue?

Does anyone have any details on the "AT" version of the MVP3 Northbridge? Was it actually a recalled part? What bugs are present if any?

Reply 1 of 3, by Anonymous Coward

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Knowing VIA, I doubt anything was recalled. More than likely they just started quietly shipping their bug "fixed" versions.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 2 of 3, by astigmatism

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I wanted to sum up my findings in the event anyone else discovers this thread in the future. I certainly welcome necro-posting 😀 In summary, I'm still not completely certain why VIA rebadged the Northbridge "AT" suffix as "MVP"

In pouring over the VT82C598MVP datasheet, I found a revision history that denotes when the name change occurred on the datasheet itself (July 26, 1998 or 3198) but no mention is made as to the purpose.Other revisions made to the datasheet at that time might suggest chipset changes but they could also be simply corrections to errors on the datasheet itself. For instance, I believe the chipset always supported AGP spec 2.0. I'll post the revisions made for July 1998 here regardless:

Removed 598 pinouts and renamed 598AT as 598MVP
Removed DDR SDRAM-II, ESDRAM, & Virtual Chan from feature bullets
Updated feature bullets and pin descriptions to correspond to production parts
Updated AGP spec support from 1.0 to 2.0 (1x and 2x transfer modes)
Fixed register definition errors: Device 0 Rx70[4], Rx73[0,4,7]
Updated AC Elec Specs - HA & TA setup times for 100MHz CPU interface
Removed DDR SDRAM timing
Moved functional timing diagrams to separate document
Fixed other miscellaneous typographical and formatting errors

I also found this statement from an enthusiast website without any official references:

VT82C598MVP revision 'CD' (made as late as 9821) seems to have some compatibility problems with certain AGP video cards (like Intel i740). Revision 'CE' (made as early as 9825) seem to fix this, and FIC also produced a BIOS update that claimed to fix it.

I guess the best thing to do here is try out an Intel i740 on the Tyan board I referenced in the opener. If the chipset was revised and rebadged simply to denote VIA had addressed compatibility issues but at the same time a BIOS revision could also do the same, it does seem like we're still missing something...

Reply 3 of 3, by Horun

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🤣 probably an issue with AGP Aperture between the i740 and VIA chipset, for a very short time it worked well in Intel based boards but nVidia within 6 months crushed the i740 and did not have the issues in many other boards (neither did ATI shortly after).
Good comparison from Phils: https://www.youtube.com/watch?v=EDibgeNzZ7c

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun