OPTi Inc.

OPTi were a chipset manufacturer for PCs. Founded in 1989, they competed against SiS, ALI, Intel and UMC for the desktop 386, 486 and Pentium motherboard chipset industry.

By 1996, OPTi were really struggling against Intel who held a large percentage of the chipset market. Redhill has this to say about OPTi: "So long as the 486 reigned OPTi was the world number one chipset maker. OPTi 386 products were excellent and their "495" and "895" i486 chipsets were generally regarded as the best ones on the market. As a chipset maker, Intel went from nowhere to world number one in just a couple of years. Before long Intel had more than 50% of the chipset market with the next biggest player having just 14%. Like all the independent chipset makers, OPTi found the going difficult after this. OPTi did not manage to produce a PCI 486 chipset (at least not one that we ever saw). Nor did they transition to the Pentium promptly. So when the long promised OPTi Viper chipset finally arrived, remembering their excellent 386 and 486 chipsets, we expected that it would be a humdinger. (After all, how hard could it be to improve on the unlovely FX and VX chipsets anyway?) We were to be sorely disappointed. It seems that the Viper had only one thing going for it, a low price.".

They also manufactured audio chipsets. This side of the business was sold in 1997 to Creative Labs.

The "OPTi Bus"

Around the time VESA Local Bus was being developed for faster 486 motherboards, many motherboard and chipset manufacturers came up with their own proprietary buses. OPTi's was called OPTi Local Bus and arrived around 1991. The slots themselves are typically brown and look similar to the old EISA bus slot but are the same length as an ISA 16-bit slot. Unlike VLB, the OPTi bus doesn't have an "ISA" part to the slot. The motherboard did not necessarily have an OPTi chipset to support the OPTi local bus.

Motherboards that used the OPTi Local Bus were:

  • Chaintech 433SCL
  • Leading Edge 486 boards
  • Orchid Superboard series

 

Motherboard Chipsets

 

SCNB (Single chip notebook) 82C463 or 82c263

Click here for a brochure from 1992.

82C281

No information on this.

82C283

No information on this.

82C291, 82C206


A 386 chipset. BIOS can sometimes report this combo as the "OPTi 349 chipset".

82C295

No information on this.

82C381

This was a 386 chipset consisting of two chips.
Motherboards known to have used this chipset were:

82C391/82C392B

The 82C392B was used on 80286 motherboards.

 

 

 

HiB (82C481, 82C482)

The "HiB" chipset was a 486 chipset with write-through cache. Dated around 1994.

82C491, 82C493

A 486 chipset with write-back cache.

82C495 / 82C495XLC

A 286, 386 and 486 motherboard chipset, which supports 80286, 386DX, 486DX, 486SX, 486DX/2 and Pentium OverDrive (P24T) processors. On a 386 motherboard, this also supported the interesting Cyrix Cx486DLC (and TI or IBM branded variants) drop-in 386 upgrade CPU. It had write-back cache. Here's a brochure for the chipset from 1992.

Some known motherboard BIOS strings that use this chipset are:
40-081L-001343-00101111-080893-OP495XLC-F - Board Image POST Image
40-0100-001123-00101111-060692-OPWBSK-F
40-040A-001107-00101111-111192-OP495SLC-8

82C495SLC

Award BIOS Chipset code: 214UE

82C496

No information on this.

82C498

No information on this.

82C499

No information on this.

Python (82C546, 82C547)

The "Python" chipset released in 1994 consisted of the 82C546 AT Bus controller and 82C547 System controller. They also work alongside the 82C206 Integrated Peripheral Controller (IPC). They were designed for the first Pentium motherboards. The datasheet can be downloaded here.

Award BIOS Chipset code: 215UM

Viper n+ (82C557M, 82C558E)

The "Viper N+" chipset was designed for notebooks. Released in 1995, it consisted of the 82C557M System controller and 82C558E Peripheral Controller, plus supporting chips. It supports ISA, VLB and PCI buses, and 64-bit CPUs like the Pentium 75/90/100/120 on 66 MHz bus frequency. It also supports the Cyrix 6x86 CPU. A brochure can be found here.

VIPER NK/N+

A mobile (laptop) motherboard chipset from 1996 that consisted of the following:

82C557M
82C558E

Viper DP

A dual processor chipset from 1994 made up of:

82C556
82C557
82C558

Viper Max (82C566, 82C567, 82C568)

Introduced in 1997, the Viper Max chipset consisted of the following:

82C566
82C567
82C568

82C571, 82C572

A 486 and Pentium motherboard chipset with support for VESA Local Bus and write-back cache. Click here for a brochure.

Known for its poor performance. Used in Compaq PCs.

Superceded by the "Viper M". It had no level 2 cache onboard but typical motherboards (Compaq included) got a COAST slot so you could install a 256 KB level 2 cache module.

PTMAWB (82C596, 82C597)

A motherboard chipset for the Pentium CPU family.
The 82C596 uses a VLB-to-PCI bridge chip, the 82C822 to implement PCI functionality. Click here for a brochure from 1992.
Motherboards that use this chipset are: TMC PCI54PV

82C682

A 386 and 486 motherboard chipset with support for the EISA bus. 486 supports write-back cache.

82C683

A 386 and 486 motherboard chipset with support for the EISA bus. 486 supports write-back cache.

82C691, 82C696

A motherboard chipset with support for the EISA bus.

EISA pentium (82C693, 82C697)

Here's a brochure on the EISA Pentium chipset, dated 1993.

VENDETTA (82C750)

No information.

scwb2 (82C801)

A 486 motherboard chipset with support for VESA Local Bus and write-back cache. Click here for a brochure from 1992.

82C802 / GREEN (82C802G) / 822

Here's a brochure for this 486 chipset, dated 1993. Supports level 1 write-back cache.

Award BIOS Chipset code: 2A4UK

Motherboards that use this chipset are:
Soyo SY-030E2

TRUE GREEN (82C895)

OPTi's final 486-generation motherboard chipset. It supports 486SLe, 486SX, 486DX, DX/2, DX/4 CPUs and write-back CPUs like the OverDrive (P24T). Motherboards with this chipset had ISA and VESA Local Bus expansion slots. Here's a brochure from 1994.

Supports level 1 write-back cache.

Some motherboards that use the 82C895 chipset are:-

419R1 Socket 3, Atrend OPTI895 Green, Dataexpert EXP4044VL

 

Graphics Card Chipsets

OPTi 92C178 (1998) - Drivers: Windows 95, NT 4.0

OPTi 82C264 (1998) - Drivers: Windows 95, NT 4.0

 

Sound Card Chipsets

Any sound card with the 82C929A chip on it is really meant for use in pure DOS or alongside another sound card in Windows. I've had greater success just running the DOS drivers (ONLY the DOS drivers) for my 82C929A-based OPTi card before completely screwing up the audio amp while trying to reverse the Stereo sound from the YMF262(the left and right audio channels are backwards on a lot of OPTi cards with discrete OPL3).

Now, as for the distorted FM, it could be one of two things:

1) If the card uses an 82C929A or 82C930 chipset along with a real YMF262 and the op-amp right after the YAC512 is an LF347, the distortion is caused by the op-amp
2) If the card uses an 82C931 chipset, it replaced true OPL3 by what's known as OPTiFM, OPTi's piece of crap OPL3 clone

The former can be fixed by replacing the LF347 by a TL074, but the latter can't be fixed as the OPTiFM is integrated within the 82C931.

If your 82C929A has an LF347 op-amp, the sound will come out distorted unless you use the DOS drivers and don't set the mixer settings too high. The YMF262 will not distort at all if your card has a TL074 op-amp.

OPTi's earlier chips are a lot better than their later ones, mainly when it comes to OPL3. Earlier OPTi chips can have either authentic OPL3 or discrete YMF262 clones which are almost exact copies of the YMF262. Later chips like the 82C931 and the later PCI-based 82C935 (more commonly known as the MachOne EV1935) use OPTiFM, OPTi's OPL3 clone, and sound like crap as a result, though not as bad as any Analog Devices SoundPort sound card(those have the worst hardware clone of the YMF262 I've ever come across). They seem less compatible, too.

OPTi Technologies sold its audio chipset business in 1997. Please keep in mind that even prior to 1997, OPTi Technologies never made sound cards. They previously sold chips for these cards to other companies, who are responsible for providing and updating drivers. OPTi Technologies does not offer any audio drivers. If you need technical support or drivers, you will need to contact the company that made your sound card.

82C924

FM synthesizer: Embedded Yamaha OPL3.

The 82C924 audio chipset provides compatibility for Ad Lib, Sound Blaster, Sound Blaster Pro, Windows Sound System and MPU-401.

MANUALS

Datasheet

 

Drivers

It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
DOS, Windows 3.1 (1.0 MB)
Windows 95 version 4.00.10 (1.1 MB)
Windows 95 (75 KB, with DirectX support)

82C925

FM synthesizer: Embedded Yamaha OPL3.

The 82C925 audio chipset provides compatibility for Ad Lib, Sound Blaster, Sound Blaster Pro, Windows Sound System and MPU-401.

MANUALS

Datasheet

 

Drivers

It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
DOS, Windows 3.1 (903 KB)
Windows 95 (76 KB, with DirectX support)

MAD16

FM synthesizer: LS-212 (OPL3 clone/copy).
Chipset: OPTi 82C928 or 82C930A.
IDE, Sony, Panasonic and Mitsumi CD-ROM headers.
Sound Blaster Pro-compatible.

MAD16 is related to the OAK OTI-601 / OTI-605 'Mozart'. The Mozart chip was developed by OAK and Media Chip, the latter now owned by OPTi.

Problems reported with Windows drivers on cards with this chipset. Click here for the OPTi chipset brochure from 1993.

This chipset was used on the following sound cards:

Drivers

It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
DOS, Windows 3.1 (569 KB)
OS/2 (311 KB)
Windows NT 3.51 (89 KB)

 

MAD16 Pro

FM synthesizer:
Chipset: OPTi 82C929A.
IDE, Sony, Panasonic and Mitsumi CD-ROM headers.

Any sound card with the 82C929A chip on it is really meant for use in pure DOS or alongside another sound card in Windows.

The MAD16 Pro is compatible with Sound Blaster Pro, WSS, has MPU-401 compatible game port (UART mode) and supports M-CD.

Click here for the OPTi chipset brochure from 1994.

Drivers

It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
DOS, Windows 3.1 (641 KB)
Windows 95 (630 KB)

 

82C930

Not PnP.
IDE CD-ROM interface.

The 82C933 is compatible with Sound Blaster Pro, WSS, has MPU-401 compatible game port (UART mode).

Drivers

It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
DOS, Windows 3.1 (806 KB)
Windows 95 (628 KB)

 

?

OPTi 82C931 chipset.

Plug & Play.
IDE CD-ROM interface.
Integrated OPL3 clone.

The 82C933 is compatible with Sound Blaster Pro, WSS, has MPU-401 compatible game port (UART mode) and supports M-CD.

?

OPTi 82C933 chipset.

Plug & Play.
IDE CD-ROM interface.
Integrated OPL3 clone.
3D sound.

The 82C933 is compatible with Sound Blaster Pro, WSS, has MPU-401 compatible game port (UART mode) and supports M-CD.

MAD32

FM synthesizer:
Chipset: OPTi 82C950.
IDE, Sony, Panasonic and Mitsumi CD-ROM headers.

Click here for the OPTi chipset brochure from 1994.