Recently picked up an inexpensive mATX motherboard for testing AGP graphics cards – the AOpen MX46-533V. The specs are pretty good for its intended purpose – socket 478 for cheap Pentium 4 cpu’s, up to 533MHz FSB support, DDR333 memory support, Universal AGP, and drivers ranging from Windows 98 SE and NT4 to Windows XP. There’s even an integrated graphics unit  in case I want to test something other than graphics cards.

The board supports hyperthreading, confirmed by testing my P4 3.06GHz HT processor in Windows XP. Initially, the board came with some mystery bios R1.02TR, and the latest official bios claimed to have fixed a few bugs related to hyperthreading. So I tried to install a newer bios, only to run into an unpleasant surprise – the official bios updater claims my board is some mystery AOpen MX46-U2CN, and refuses to work. Searching the web, seems like the mystery MX46-U2CN board never existed, and yet it says “AOpen MX46-533V” right on it. So, instead of relying on the official bios updater, I downloaded Award Winflash, and forced it to flash all the bios blocks using the latest bios image from AOpen. To my relief, the update went smoothly, and the board now identifies itself correctly.

Now for some facts and details:

• The integrated SIS 315 gpu does not support hardware T&L. I saw mentions on the Web that the discrete SIS315 graphics card supports hardware T&L. Well, the IGP version certainly does not. Not that I was planning on gaming with it.
• The IGP causes a decrease in memory performance. Inserting an AGP graphics card disables the integrated graphics, and brings memory performance in line with expected results. Using a PCI graphics card only slightly improves memory performance compared to using the IGP, but not to the same level as an AGP card.
• Under Windows 98 and its default DirectX 6 runtime, the integrated gpu will not support hardware 3D acceleration. Installing DirectX 7 or later fixes the problem, and 3D acceleration works.
• The board plays ok with bridged late AGP cards. At least my Visiontek Radeon HD3850 AGP worked without problems under Windows XP.
• It also plays ok with flaky old AGP 2x cards like the Trident 9850. On Via 133 boards, this card would usually always lock up in full screen 3D applications. But here, it just works. To be fair, the newer Via KT333 has no problems with it either, but I wouldn’t put my Asus A7V333 board in the “cheap beater” category.
• Even more impressively, the board plays well with my 3dfx Voodoo (the original). On old Via 133 or Intel 815 boards, even a 600MHz Pentium 3 would cause problems, such as old DOS Glide games being unable to detect the card, or texture corruption in other games, simply because the processor is too fast. On a faster AMD Athlon system, it’s usually instant hard lockup with a checkerboard screen. And yet, with this board I can run a 3GHz Pentium 4 with DDR memory, and the Voodoo has no problems running Tomb Raider or GLQuake.
• All the USB ports are USB 2.0. Except if you’re using Windows 98. Then these ports work at USB 1.0 speeds only.
• The bios has settings for base clock, memory speed and timings, and IRQ assignments. No voltage adjustments. No cache disabling.
• Hyperthreading can be disabled in the bios. This is useful if you want to run Windows 98, or some applications like 3DMark2000, which don’t play nice with HT.
• There are no SATA ports. You’re stuck using IDE drives only. For a beater testing board, I suppose that’s not a big deal.
• If experiencing hard lockups in 3D games, move USB from EDB Bus to PCI Bus in the bios. If using integrated audio, move it to PCI Bus too. This was necessary to stop my Matrox G200 from lockups in 3D games. On the other hand, keeping these components on EDB Bus is what allows a 3dfx Voodoo to work flawlessly in this system.
• The integrated sound chip supports Sensaura 3D audio. That was a nice surprise the first time I plugged in speakers and fired up Unreal.

Overall, the board has lived up to my expectations, and even threw in a few pleasant surprises. No major annoying issues or quirks or compatibility problems. There is passive cooling for the north bridge and south bridge, which I like. Even the VRM MOSFETs have a heatsink for extra cool points if nothing else. Currently I have it set up dual booting Windows XP and Windows 98 SE off a single 120GB hard drive, 512MB RAM, and a 2.53GHz Pentium 4. Why not use the 3.06GHz P4 HT? Well, the 2.53 is my beater cpu, and fast enough. I have other plans for the 3.06, plus that way I don’t have to enable or disable HT, depending on what OS I’m booting. Because having a 3.06GHz P4 HT and not using HT at all seems like a waste. On the other hand, this board is so well behaved, I might have just unexpectedly built myself the perfect Windows 98 retro gaming PC without even realizing it. If this keeps up, I might just have to rethink the logic of keeping my 440BX Pentium II systems as my retro PC.