Documentation, Downloads, Drivers
Hardware and BIOS aside (for the moment) - the first big positive aspect when you chose a mainboard of a still existing manufacturer for your retro build, is, that you'll most likely won't have too much trouble finding documentation and BIOS files.
The Support Site for the A7V266-E can be found easily when you go to your search engine of choice and type "a7v266-e support".
Asus still offers the manual, the latest BIOS versions and even drivers for download.
Unfortunately, Asus does not bundle a BIOS flash tool with the BIOS downloads, and the utility is also not available for download in the BIOS & Firmware download section of the support page. The required "Aflash" Utility can be found under Driver & Tools - there you have to select "Others" at the "Select OS" drop-down list:
There is a CPU Support list directly on the support page, but Asus also offers a global CPU Support search, where you're not only able to search for a specific mainboard model but also the other way round: If you have an old CPU laying around, you can use the search form to find compatible mainboard models and maybe to get inspiration for your next retro build.
You can find it here: https://www.asus.com/support/cpu_support
System Setup and Usage
The first thing I do when I setup a retro system, is to plan how to distribute the expansion cards across the PCI slots. This is crucial for Windows 98SE based systems, because the one thing you don't want are ressource conflicts.
So after the parts are chosen and collected, I grab the manual and hope that there is useful information, which PCI Slots share ressources with each other, the AGP port and onboard devices.
Fortunately, Asus has always been known for good documentation in that regard and the manual of the A7V266-E(X) is no exception. There is a table that shows, which PCI slots sits on which INT line and also which onboard devices and PCI slots share the same ressources. This is close to perfect.. if this little mistake wasn't there:
According to the table, the AGP Port shares ressources with two PCI slots, which are on different INT lines. Since a videocard only uses one IRQ (at least if it is not a card with a TV Tuner like a Radeon All-in-Wonder for example), it will only allocate an IRQ on the primary INT line, which is INT-A. I tested it for myself - the AGP ports indeed shares ressources with PCI slot 2 and (presumely) the usesless ACR slot. PCI slot #3 and the onboard audio controller sits on INT-B.
From a technical point of view, the INT routing is a little unfortunate. Most motherboards have the first PCI slot sharing the interrupt with the AGP port, which is the better option in my opinion. Normally you want to keep that slot free anyway, so that the graphics card has a little room to breathe. So with this solution..
- ..you cannot use PCI Slot #2 for anything else than a Voodoo 2 card (which does not allocate an IRQ)
- ..you'll want to keep PCI #1 free, to prevent your graphic card from melting
- ..and since Asus decided, that 5 PCI slots and no ISA Slot are sufficient, you have a total of 3 PCI slots at your disposal, which qualify for different usecases.
Let's have a look at some combinations, that should work the best from a theoretical point of view.
Example 1: AGP card, 2x Voodoo 2, Storage Controller, Soundcard, NIC
This is almost impossible, and you will end up putting extreme stress (in terms of temperature) on your components. It would look like this:
- PCI1: Voodoo2
- PCI2: Voodoo2
- PCI3: Soundcard (onboard sound disabled)
- PCI4: Storage Controller
- PCI5: NIC
Because they do not allocate IRQs, the two Voodoo2 cards (which generate a lot of heat by themselves) would be installed directly beneath the AGP card. This is the only valid location for the cards (given we want to install them with the default internal SLI cable), because the second PCI Slot shares the IRQ with the AGP card and PCI #1 shares ressources with PCI #5, USB and onboard IDE. So these two PCI slots should ideally not be populated with cards that need an IRQ.
Since Voodoo2 cards are quite large, the cooling of the AGP card would be massively affected and the Voodoo2 card in PCI #1 would also get very hot, quite possibly too hot. Soundcard and storage controller positions can be interchanged, but have to be in PCI #3 and #4. The LAN card can in theory change places with the Voodoo2 card in PCI Slot #1, BUT you would have to craft a very long internal SLI cable by yourself. A positive sideeffect would be, that a NIC normally is quite small and wouldn't affect the cooling of the AGP card too much.
If an additional storage controller is not part of the system, there are some more options.
Example 2: AGP card, 2x Voodoo 2, Soundcard, NIC
- PCI1: FREE
- PCI2: Voodoo2
- PCI3: Voodoo2
- PCI4: Soundcard (onboard sound disabled)
- PCI5: NIC
The first PCI Slot is free then, the pair of Voodoo 2s and the soundcard move one slot down. Another option is, again, to craft a longer SLI cable and let the second Voodoo 2 card change places with the soundcard.
In reality, however things turned out to be a little different. I did the first testing without the Voodoo2 cards and installed the soundcard into PCI #4, the NIC went into PCI #5.
The first issue I encountered (even before the the Voodoo2 cards went into the system), was, that the onboard audio seemingly did not deactivate properly when I deactivated it. I went into the BIOS to Onboard Peripheral Control and set “Onboard AC97 Audio Controller” to “Disabled”, but the “Unknown Multimedia Device” still showed up in the Windows device manager, and PCIList.exe also found the C-Media audio chip, which also still allocated an IRQ.
After looking around in the BIOS, I found another option in the Advanced Chipset Features sub-menu. Usually, you would expect to only find performance-relevant settings there, but at the bottom of this menu, there is also the possibility to set “Onboard PCI Audio Controller" to "Disabled". This did the trick - the onboard audio was finally “gone”. By the way - on the same page, there are also options to deactivate the onboard IDE channels individually and also the “Onboard ACR LAN Controller”. All these settings actually don't belong there in my opinion, and should be found in the “Onboard Peripherals” section. This is a pretty bad BIOS design.
After this was sorted out, I did all the testing apart from 3dfx benchmarks, and did not come across any issues. The system ran fine, even with all memory and chipset settings configured to the fastest values.
Then, I installed the Voodoo2 cards. The installation went fine and after the reboot, both cards were present and functional - according to the device manager. However, when I tried to open the display settings to check the SLI status in the Voodoo 2 tab, the system froze. I removed the NIC and the Soundblaster Live!, but the issue persisted. The only solution was to install the two 3dfx cards into PCI #4 and #5, the SB Live! into PCI #3 and the NIC into PCI #2, now sharing its IRQ with the AGP card.
After this, everything ran fine again, and I was able to complete all benchmarks with the pair of Voodoo2 cards. The IRQ sharing between the NIC and the AGP Port caused no problems during the testing, but of course I didn't use much networking during the time the AGP card was heavily used. This constellation may or may not cause issues, this depends on the networking card's chipset (I definitely had problems with realtek-based NICs sharing their IRQ with the AGP card) and maybe also on the VGA chipset, BIOS-, and driver versions and so on. The best thing you can do, is to avoid IRQ sharing of high bandwidth and/or -priority devices like graphics-, audio- and storage cards.
Apart from the installation of the PCI cards, the setup of the A7V266-E is quite simple. The only important thing to know, is how to activate the "Jumperfree Mode" with the “JEN” jumper. In "Jumperfree Mode", the board always boots with the FSB set to 100 MHz, whenever a CPU is installed. If you enter the BIOS afterwards, the board takes you to to the advanced settings page, where you can set the FSB to 133 MHz (when using a FSB133 CPU of course). Everything else is autodetected.
There is also a “THERMTRIP” jumper in the top right corner, which switches the method of temperature measurement for different CPU models. When set to “Athlon XP”, the internal temperature diode of the CPU is used for measuring the CPU temperature. The Athlon 1200C used during the review worked with both settings and reported identlical temperatures, so I recommend to leave it in the “Athlon XP” position.
A thing to mention is probably, that the “Jumperfree Mode" is not really “jumper-free". Especially in terms of overclocking, there are still settings that can't be configured from within the BIOS. The first thing is the board's overvoltage mode. There are two jumpers ("Over1" and "Over2") that have to be adjusted. With these jumpers both set to 1-2, an +0,300V offset is applied to the configured VCore.
Since the lowest configurable VCore (Thunderbird) is 1,750V, the “overvoltage mode" starts with 2,05V (the VCore setting in the BIOS still reports 1,750V, the offset is not visible). This is generally a nice option to have, but I don't recommend using these high voltages, except for short testing sessions. Otherwise, this mode will slowly degrade and kill the installed CPU, even if the cooling is sufficient.
The other thing, that is not configurable via BIOS, is the I/O voltage. There are four settings ranging from 2,50V up to 2,80V, which let you select the supplied voltage for chipset and memory. According to the manual, AGP and PCI voltage is also modified by this setting. So keep that in mind, if you use a rare and/or expensive videocard in this mainboard. This kind of voltage control is nice to have for some overclocking, but it would be even nicer, if these settings were available in the BIOS. Since the jumpers are located left from the AGP port, adjusting these settings is not the most convenient thing to do.
Asus A7V266-E (VIA KT266A)
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Layout
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Features
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Overclocking Options
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Compatibility
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Documentation & Support
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Performance: GeForce 4 Ti 4200
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Performance: Voodoo 5 5500
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Performance: Voodoo 2 SLI
OVERALL
| Pros | Cons |
| + Great performance | – Inconvenient OC / voltage settings |
| + Great CPU support | – Layout issues |
| + Good PCI and IDE performance | – Bad BIOS design |
Hi,
villeneuve@Voodooalert here,
I got my A7V266-E Rev. 2.00 out of a Targa Tower PC which was purchased brand new back then by the father of one of my best friends.
Once I got it I also stumbled across the mess with the model numbers. My conclusion always was and still is that Asus shortly before they got the VT8233A from Via made an OEM-version for Targa with the other changes that were already in stock for the -EX-model. The BIOS downloads from Asus and Targa for the E-model are bit-identical so the hardware must be identical apart from those visual differences. Greets!
Hi, thanks for the comment!
Seems to be a very reasonable explanation, thank you for the info 🙂