Last week, I saw a system that interested me. Usually I see stock Dell or HP machines from the mid-2000s, but this system was inside an AT-style enclosure. My interest was naturally peaked. The system did not have a cover and I could see a socket 7 motherboard. There was no heatsink on the CPU, which identified itself as an AMD K6-2 350MHz. I did not need any more advertising, I had to have this machine. Three discrete trips to the bin later, I had the CPU, the motherboard on a removable tray, the CPU heatsink and all the header connectors I saw. I did not take any disk drives, I do not need floppy or CD-ROM drives and there is an unwritten rule about taking hard drives (to protect residents against identity theft.) I left the case, drives and power supply for the recyclers.
|The unknown motherboard|
- Socket 7 or Super Socket 7 CPU
- 3 x DIMM SDRAM
- 2 x IDE, 1 x Floppy
- 1 x VGA (header)
- 1 x Parallel, 1 x Serial (header)
- 1 x PCI Audio, Game/MIDI & Modem (header x 2)
- 1 x LAN (header)
- 1 x AT Keyboard connector
- 1 x PCI, 1 x ISA (not shared)
- AT and ATX Power Connectors
- 1 x CPU Fan Header & 1 x Case Fan Header
- 512KB of External L2 Cache (this board supposedly has 2MB : http://www.ebay.com/itm/PC100-VIAGRA-SUPER-SOCKET-7-SOCKET7-MOTHERBOARD-WITH-HEATSINK-MODEM-SOUND-VGA-/221616294322)
- 2 x USB 1.1 ports (via header)
As this is a late AT class motherboard, there are headers and ribbon cables for just about everything.
Identifying the Motherboard :
|Not to busy looking from this angle|
Obviously, the VT82C691 is not the chip and the VT82C501 looks better than the VT82C598 because the VT82C501 advertises integrated graphics, which fits with my board. Therefore, the Northbridge is a VT82C501. The MVP4 is otherwise identical to the MVP3.
There is no official name of the motherboard or who manufactured it on the board itself, but judging by this thread it is highly likely a PCChips product. http://www.vogons.org/viewtopic.php?f=46&t=46530&start=0
The heatsink on PC Chips' boards is very distinctive. Other manufacturers like ASUS and Gigabyte proudly identify themselves, but PC Chips left their identity to their golden heatsink. It uses a VIAGRA PC100 chipset. No chipset was ever more unfortunately named and a Google search does not really work well.
Therefore, my motherboard is a PC Chips M585LMR. Its PDF manual can be downloaded from here :
There is a thread about the motherboard here : http://www.vogons.org/viewtopic.php?t=44260&p=435581, but without pictures it would be difficult to associate this board with the thread.
Integrated Functionality :
This chip incorporates the Trident Blade 3D AGP 3D Accelerator. http://www.anandtech.com/show/248
The LAN is provided by the Davicom 9102F chip. It is a 10/100Mbit PCI-based LAN card, and Windows 9x has drivers for it. It cannot be disabled, but there is no reason you have to use it except that wasting a PCI slot on a LAN card is silly.
The audio and modem is provided by the SoundPro HT8738AM chip, which has dual functionality. The audio portion is provided by a core functionally identical to the C-Media CMI8738. The modem capability is provided by a core fundamentally identical to the PCtel HSP56 MicroModem. This is a Winmodem, so do not expect good performance.
The only jumpers on this board are JBAT1, JP2, JP4 and JP5. JBAT1 clears the CMOS memory, JP2 enables and disables the onboard audio and modem functionality and JP4 enables and disables the onboard LAN. JP5 selects the SPDIF voltage output for the SPDF I/O connector, allowing for 5 volt or .5 volt. 5 volt is suitable to power an optical or TTL output, while 0.5 volts is appropriate for a coaxial peak-to-peak output. There is also an audio and modem disable in the BIOS, but hardware disable seems better than software disable for completely eliminating the device from Windows.
There is information silkscreened for JP6 (CPU multiplier selection) and JP9 (front side bus speed selection), but no pins or dipswitches on the board to access these selections. These settings are entirely controlled by the BIOS.
|Then you look on the other side of the board|
COM1 : Serial Port, standard 10-pin header (pin 9 is key)
PRINT1 : Parallel Port, standard 26-pin header (pin 26 is key)
VGA : Monitor Display port, standard 16-pin header. Uncommon but not unknown, pin 16 has no connection)
LAN1 : RJ-45 port module, non-standard.
DAA1 : Winmodem 2 x RJ-11 module, non-standard. This does not have a ribbon cable, it attaches directly to the motherboard and its header is positioned so the module aligns with a case slot. This can be found by searching for PCTel Fax/Modem DAA module
SOUND1 : Game/midi port and line in/out/mic, 26-pin non-standard header. The first 16 pins of this header are for a gameport, and that is standard (pin 16 not connected). The subsequent 10 pins are used for the audio jacks, but do not follow the standard for front panel audio designs. Instead, 4 pins are used for the stereo line in, 4 pins for the stereo line out and 2 pins for the microphone input. This header adapter appears to be identical : http://www.ebay.com/itm/new-PC-Audio-cable-with-Line-in-Mic-Line-out-for-Asus-Intel-MotherBoard-MORE-/121321453854?_trksid=p2141725.m3641.l6368
ATX FORM : PS/2 mouse, Infrared Port, and 2 x USB ports, 18-pin non-standard, pin 14 is the key. I do not have this particular connector, but it appears identical to the one sold here : http://www.cablesonline.com/usbatxforcar.html
USB1 : USB1.1 x 2 ports, 8-pin semi-standard. The standard ribbon cable has 10 pins, but pins 9 & 10 are no connected. A typical adapter should work. This board supports 4 USB ports between this header and the ATX FORM header.
CD-ROM : Although not labeled as such, there are what appears to be two CD-ROM headers. One of them has a white snap-in box around the pins. The white box should have the pins in GLGR format, while the no-box header should have the pins in the LGGR format.
SPDF I/O : 8-pin header, pin 3 is key. Provides coaxial spdif input and output and stereo line input with an adapter which I cannot find.
J7 : 2-pin header for CD-ROM SPDIF input. This cannot be used if the external SPDIF bracket is being used.
J4 : 8-pin header, pin 8 is key. Not documented in the manual
There is a header, J11, for the switches, LED and speaker. This header is a little odd. The 4-pin header for the speaker and the 3-pin header for the Power LED are connected horizontally, but the other LEDs and the Power/Suspend switch are connected vertically. They all use 2-pins, so this will work. The silkscreening on the motherboard does not make this crystal clear.
Special Features :
The motherboard theoretically supports up to 768MB of RAM in its three DIMM slots. However, not all of this RAM is cacheable. 2MB cache systems can cache up to 508MB, 1MB cache systems up to 254MB and 512KB boards only 127MB. If for some reason you need more RAM than this, the performance of the extra RAM will suffer. My system reports itself as having 512KB of RAM, so a single 128MB stick of PC-100 SDRAM will suffice. PC-66 SDRAM is also supported.
Front side bus speeds supported are 60, 66, 75, 83, 90, 95 and 100MHz. If the silkscreening is to be believed, this board supports multipliers from 1.5x to 5.5x. This pretty much encompasses the world of the Socket 7 and Super Socket 7 CPUs, from a Pentium 90 (1.5 x 60) to a K6-2+ at 550MHz. These CPUs do not have locked multipliers, so for example, my K6-2 350 can be unclocked to 90MHz. The system can run CPUs with 3.3v to 2.0v core voltages.
The Southbridge chip supports UDMA/66 IDE. This limits you to 28-bit LBA, so hard disk drives should be no more than 120GB. Windows 9x also has similar limits.
The Trident Blade 3D integrated graphics cannot be disabled. The integrated graphics will use 4MB or 8MB of system RAM for a frame buffer. Discrete graphics cards using this chipset may use SGRAM instead of SDRAM. There is Direct 3D support for 3D accelerated graphics as well as an OpenGL ICD for Quake-engine game support. There is also hardware support for DVD decoding. This graphics controller is AGP based, but does not take full advantage of the AGP specification. When it came to 3D accelerated graphics, an nVIDIA TNT card smoked the Trident, as shown in the Anandtech article linked above.
The Trident adapter supports 640x480x32bit @ 160Hz, 800x600x32bit @ 160Hz, 1024x768x32bit @ 120Hz, 1280x1024x16bit @ 100Hz and 1600x1200x16bit.@ 85Hz. DOS VGA and SVGA compatibility appears to be solid.
The CMI8738 chip appears to be a quite decent all-rounder. It supports DirectSound/DirectSound 3D, EAX 1.0 and A3D 1.0 with updated drivers. It provides Head-Related Transfer Functions for 2-speaker 3D positional audio. It can record and output 24-bit SPDIF and will output 5.1 AC3 from DVDs. The SOUND1 bracket supports using four speakers by repurposing the line-in connector.
The CMI8738 will emulate a Sound Blaster 16. It possesses an excellent FM synthesis core. I do not know if it was licensed from Yamaha, but it sounds very close to a Yamaha YMF-724 FM recording. If you want to use an ISA card for DOS games and keep the PCI audio, you can move the I/O ports of the Sound Blaster, MPU-401 and/or FM Synthesis to ports that will not be used. Interestingly, the VIA Southbridge also supports Sound Blaster Pro emulation, but this may be disabled on the motherboard or the chip itself to allow the CMI8738-based chip to be the only on-board audio system.
|Meet your expansion options|
This board is on the edge of the AT to ATX transition. Most Socket 7 and even Super Socket 7 boards used the AT form factor, while virtually all Pentium II boards used ATX. The AT keyboard connector has purple plastic, which is a PC97 requirement. With the ATX FORM bracket and an ATX power supply, this system becomes a fully ATX compliant computer with its various suspend and sleep functions. Use of AT power supplies makes fewer of these energy saving options available. I personally find sleep, suspend and ACPI functions a nuisance. I prefer to turn a system on and turn a system off rather than worry about whether it will wake itself from sleep.
The board is very small for the period, not much larger than a mini-ITX board. Even so, very little that an average user may need is left out. A parallel port and one serial port is provided. The one serial port is intended for a mouse, and instead of a second serial port you get a built-in (if crappy) modem. Use the ATX FORM bracket and a PS/2 mouse and you can rescue the serial port for something else. By adding basic 3D accelerated video and audio and a LAN, there is not a heck of a lot of need for expansion for most people.
The ISA slot is in line with the switch and panel headers, so using long cards with this system may be tricky. The PCI slot is in line with the secondary IDE port, so caution is advised with using a long PCI card.
If you want to use this board for 3D gaming, you may want to add a 3D accelerator. A Voodoo, Voodoo 2 and PowerVR PCX1 or PCX2 are add-on boards without 2D capabilities. They should be able to co-exist without difficulty with the on-board video. Because Voodoo 2 SLI requires 2 PCI slots, the only way you will be able to use Voodoo 2 in SLI is by obtaining a Quantum3D Obsidian 2 X-16 or X-24, which combines two 8MB or 12MB Voodoo 2 boards onto one board.
Building the System :
|The 486 motherboard had to get the boot|
There is no way this board will fit inside an modern ATX case. The mounting holes for the motherboard are in different places in an ATX case and there are not enough common holes to give this AT board sufficient support. Even if you remove the ATX I/O panel to allow you access to the AT keyboard connector, the expansion slot holes in an ATX case do not correspond to the expansion slots on the board.
|I'll win no prizes for my cable routing|
|Lots of ribbon cables|
The ATX connector still did not work. The silkscreening for the switch/LED block was a little confusing. I did not realize until I found and read the manual that the 2-pin connectors were to be inserted vertically, not horizontally. I figured they were inserted vertically just as the other connectors, which is how they are inserted in my ASUS P3B-F. Once I inserted the power switch connector vertically in the last pair of pins, the board fired right up.
|So much for that AWE32 I wanted to put into the ISA slot|
The system did not come with any RAM, so I grabbed a 64MB and later a 128MB stick of PC-100 SDRAM I had lying around, the system did not have any trouble with the RAM.
Installing the OS and Drivers :
I was only prepared to use a 540MB hard drive for experimentation. I decided to use Windows 95 for a change, since it is smaller and faster with lower end hardware than Windows 98. I have a Windows 95 OSR2.1 CD, which I found out was not bootable. A truly fresh install will require a boot disk with a DOS CD driver and MSCDEX. Installing the operating system was fast and easy. Getting the drivers to work, well that was not easy.
|A streamlined boot screen|
|Only 512KB of External Cache, I want my money back!|
|The OS installed in the exposed system|
You have to install the card using the setup program, not the Add/Remove Hardware, in order to obtain full 3D capabilities. I had a non-working Diamond Monster 3D in the system, and it seems that it was blocking the Trident setup program from working. Unfortunately, the pickiness of the drivers means that they really cannot be upgraded.
|Windows 95 stripped of all its nonsense|