Introduction
Maybe you can still remember the article Motherboard Comparison Epox EP-7KXA vs. Asus K7V, in which I pointed out the problems that Windows2000 has with the CPU-to-AGP bridge of the VIA Apollo KX133. Since this time we’ve done a whole lot of testing with Athlon-motherboards that are based on this VIA chipset, as found in our recent KX133 Motherboard Roundup and we’ve found out a lot more about this annoying issue.
What We Know So Far
Operating systems like e.g. Windows98 or Windows2000 recognize the different components on the motherboard of a system via the device numbers that are reported by the motherboard BIOS, something that I already pointed out in the above mentioned article. This is not necessarily too much of an issue, because many of those motherboard components work just fine, regardless if the operating system recognizes them or not. In case of VIA’s CPU-to-AGP-bridge in combination with Windows2000 the story is a bit different. There simply won’t be any AGP-support, if the CPU-to-AGP-bridge doesn’t get recognized by Windows 2000. This situation is obviously unacceptable, since e.g. frame rates of no more than 70fps in Quake 3 Arena are the result, regardless which CPU is being used.
As you remember, VIA’s KX133 reference board as well as Asus’ K7V motherboard both report ‘8598‘ as the device number of their CPU-to-AGP bridge, while Epox’ 7KXA is reporting ‘8391‘. Unfortunately Windows 2000 doesn’t care much for ‘8371’, so that you won’t have AGP-support under Win2k with the 7KXA, unless you change the file’machine.inf’ as described in the above mentioned article. This situation led me to the conclusion that Epox was doing something wrong. Our KX133 board test showed however, that the situation is very different. Epox is not at fault.
Little Tricks vs. Insufficient Support
Believe it or not, ‘8391‘ is the actual correct device number of the CPU-to-AGP-bridge of VIA’s Apollo KX133. ‘8598’ is the number of the CPU-to-AGP-bridge of VIA’s good old MVP3 Socket7-chipset! VIA as well as Asus were/are using a trick, which takes advantage of the fact that it doesn’t matter which of VIA’s CPU-to-AGP-bridges is actually being used by a system, since VIA’s AGP-driver is the very same for either of them. As a matter of fact, the Apollo KX133 was NOT implemented into the Windows2000 driver support, despite VIA’s claims on their own website. Instead you have got to make Windows2000 believe that the system is equipped with a MVP3 CPU-to-AGP-bridge, so that it installs and initializes VIA’s AGP-driver ‘viaagp.sys’.
We found in our KX133-motherboard roundup that only Asus was shrewd enough to use the little ‘dirty’ MVP3-8598-trick to make sure that AGP gets enabled in their K7V under Windows2000. All the other motherboard makers are reporting ‘8391’, with the results that a normal Windows 2000 installation will leave the AGP disabled unless you are using the ‘machine.inf’-trick, making Windows2000 believe that ‘8391’ is also MVP3’s CPU-to-AGP-bridge.
A New VIAAGP.SYS
Frank Voelkel, our new motherboard specialist, who made himself a big name as one of the best motherboard reviewers already when he was still working for the German PC Professionell Magazine, was close to losing his believe in technology when he started to test the KX133-motherboards under Windows 2000. The majority of those new Athlon motherboards would fail to start or run Windows 2000 sooner or later, or the systems showed mediocre performance. One of the main reasons for this issue is the ‘viaagp.sys’ AGP-driver that comes with Windows2000, which is not exactly very stable or reliable.
After a lot of moaning and groaning we finally received some help in form of a new ‘viaagp.sys‘ file, which came from Asus of course – talking about good customer support. One would have expected it from VIA instead really. You install it by starting Windows 2000 in safe mode (press F8 at the first screen of Win2k’s bootup process). Boot into safe mode, locate the old ‘viaagp.sys’ in the directory ‘winntsystem32drivers’, rename it to e.g. ‘viaagp.sys.old’ and copy the new ‘viaagp.sys’ in this directory. This new AGP-driver remedied a lot of our problems. Systems that didn’t want to start Windows2000 once NVIDIA’s latest 5.xx drivers were installed were suddenly able to reach the desktop and systems that crashed continuously became a lot more stable.
… VIA Is Working On It …
I am sure you will agree that the situation for owners of Athlon-platforms with VIA’s Apollo KX133 chipset that want to run Windows2000 is still very far from ideal. What we all should expect is a flawless and painless installation under Windows2000 that doesn’t require any tricks to enable the AGP. In plain English this means that VIA has got to supply a Win2k AGP driver installation software for KX133 instead of falsely claiming that KX133-support is already built into Windows2000. Throwing in a STABLE AGP-driver as well would give this procedure an even nicer touch …
