Motherboard Head to Head: Epox MVP3G2 vs Tyan S1598

Here's where the problem is, although Tyan takes advantage of the integrated hardware monitoring features of the 686A, they do not take advantage of the AMR support or offer any integrated Audio/Telephony options meaning that the only advantage Tyan gains from using the 686A is integrated hardware monitoring which is already present on the Epox board in the form of the Winbond 83781D controller.  This would be fine if there was no difference in price, however the 686A is naturally a more expensive solution and thus drives the manufacturing price, and thus the retail price of the S1598 up above that of the Epox G2.  Keep in mind that Tyan states the on-board Audio is a manufacturing option, meaning that it could make it into some motherboards, in which case the added cost could be justified however it is unlikely that you'll see too many boards with that option.

Now for an explanation of the mysterious discrepancies in North Bridge model numbers.  If you recall back to the introduction of the MVP3 chipset at the end of 1997 (it didn't ship until 1998), there were quite a few problems related to the chipset itself and many AGP adapters including the, at the time, recently released Intel 740 graphics chipset.  In order to correct this problem, VIA released an updated revision of the chipset (Revision CE for short) and all was good.  VIA's documentation reflected this change made in July of 1998 by removing all references to the first 598AT North Bridge and replacing them with references to the new name, the 598MVP.  From that point on, the 598AT and all revision CD boards were associated with the "older" MVP3 chipset and the newer 598MVP Revision CE boards were associated with the "new" and "bug free" MVP3 chipsets.  There was no questioning this until Tyan's latest board arrived in our lab featuring the 598AT North Bridge, a supposedly discontinued part.

The Two North Bridges

A quick email off to VIA asking to shed more light on the issue resulted in a confirmation that there are in fact two different North Bridge chips but nothing more than that, a tad disappointing, so we had to turn to other sources to look for an explanation...and we got exactly what we were looking for.  It turns out that the current MVP3 chipset features a single North Bridge the VT82C598 and is manufactured under two different names depending on its final destination, with the 598AT being the OEM marking and the 598MVP being the marking used for retail distributors.  Both markings are just that, markings, and aren't in any way related to the original MVP3 release.  For whatever reason, VIA refused to explain this very simple situation to us, however now that it has been cleared up, the points against Tyan have been washed away.   

The advantage is once again tossed to Epox due to their lower cost.