DOS Days

Cirrus Logic

Cirrus Logic was a graphics chipset manufacturer for the IBM PC and its compatibles. Founded in 1984 in Silicon Valley, their chipsets became very popular due to their low cost and high degree of compatibility.

The 1987 they entered into a contract with VideoSeven to design and manufacture a VGA chipset to VideoSeven's specifications. This was released as the CL-GD410/420.

During the early 90s, when compared to other Windows graphics accelerator cards from Trident, Oak, and Paradise (Western Digital), the Cirrus Logic usually outperformed them all.

In 1991 the company acquired Crystal Semiconductor, an audio mixer/DSP chip company. In 1992 they bought AcuMOS, a video chipset company who designed and manufactured chipsets called "AVGA1" and "AVGA2". These were rebranded in late 1992 to the CL-GD naming format.

Here are their cards in chronological order:

ISA Cards VLB, PCI and AGP Cards
ISA Graphics Cards
CL-GD510/520 (1988)
CL-GD610/620 (1989)
CL-GD5320 (1990)
CL-GD5410 (1991)
CL-GD5401 (1992)
CL-GD5420 and CL-GD5421 (1992)
CL-GD5422 (1992)
CL-GD5402 (1993)
CL-GD5426 (1993)
CL-GD5428 (1993)
VGA 1024i and VGA 1024i Plus (1989)
VRAM II (1992)
Win.VGA / Win VGA (1992)
Win.Pro / Win Pro (1993)
VLB and PCI Graphics Cards
CL-GD5424 (1992)
CL-GD5425 (1993)
CL-GD5426 (1993)
CL-GD5428 (1993)
CL-GD5429 and CL-GD5430 (1994)
CL-GD5434 and CL-GD5436 (1994)
CL-GD5440 (1995)
CL-GD5446 (1996)

AGP Graphics Cards
CL-GD5464 (1995)
CL-GD5480 (199?)



Launched: 1991
Bus: 16-bit ISA

The CL-GD5410 was an ISA Super VGA chipset. It was installed on low-to-mid range DRAM-based cards (accelerated), and some laptops. It is known for being among the first to integrate the graphics card components into a single chip (built-in RAMDAC and clock generators).

CL-GD5434 / 5436

Launched: 1994
Bus: ISA, VLB and PCI
Memory: Up to 4 MB
Memory Clock: 60 MHz (5434) or 80 MHz (5436)
Memory Sockets: Typically 40-pin SOJ
Core Clock: 135 MHz
RAMDAC: 15/16/24-bit

The CL-GD5434 was part of the "Alpine" family of chips, now with a 64-bit internal memory interface. Only supports 64-bit mode if equipped with 2 MB memory. Commonly equipped with 1 MB. 32bpp True Color support, it also had a 64-bit BitBLT engine. Only the CL-GD5434 was also available on the ISA bus.

The CL-GD5436 was simply an optimized version of the 5434, adding support for EDO DRAMs thus supporting a faster memory clock. Packed-24 acceleration.

Found on:

  • Diamond SpeedStar 64
  • Diamond SpeedStar Pro SE
  • Orchid Kelvin 64
  • MVGA Alpine PCI
  • Fastware VC922C (CL-GD5434)
  • Intel Corp - FCC ID: EJMPCICL543X
  • Powertech Electronic Co Ltd VCC34 (FCC ID: KEGPTPCIVGA3A)
  • American DataCom Inc - FCC ID: IFTGD543XPCI
  • Gainward Co Ltd (Taiwan) - FCC ID: ICUVGA-GW203
  • Cirrus Logic - FCC ID: J6NGD543XPCI



Launched: 1995
Bus: VLB or PCI
Memory: 512 KB, 1 MB or 2 MB FPM
Memory Clock: 60 MHz
Core Clock: 86 MHz
RAMDAC: 24-bit

The CL-GD5440 was essentially a CL-GD5430 with an integrated CL-PX2070/'85 motion-video acceleration chip (CL-GD54M40 has integrated filters). The core clock runs at 86 MHz, the memory at 60 MHz.

Found on:

  • Joytech Computer Co Ltd (Taiwan) - FCC ID: FQI54X62L



Launched: 1996
Bus: PCI
Memory: 1 MB or 2 MB EDO

The CL-GD5446 was a 64-bit Alpine VisualMedia accelerator. 2D-only. It added motion-video acceleration to the CL-GD5436.

Found on:

  • STB Nitro 64V
  • Joytech Computer Co Ltd - FCC ID: FQI54X62L
  • SR-V641-E
  • Palit Microsystems Inc Daytona 64E (FCC ID: KC8GUIVGAS1)
  • Hightech Information System Ltd (HK) - FCC ID: KBIGD544XP


Launched: 1995
Bus: AGP
Memory: ?

The Laguna VisualMedia family of 2D, 3D, and video accelerators. the CL-GD5464 and CL-GD5465 included 3D acceleration (PCI or AGP). These chips use a single channel of RDRAM memory, providing up to 600 MB/s bandwidth. The '62 lacks 3D acceleration. All include a BitBLT engine, video windows, and 64×64 hardware cursor.

"Cirrus Logic claims it has the graphics accelerator equivalent of the Jaguar XJ220 on its hands. Its new VisualMedia accelerator, "catchily" named the CL-GD5462, can shift a whopping 500Mb of data around every second.

The device is crammed with technology which enables it to handle video and 3D work at jaw-dropping speeds. It numerous features include line and polygon drawing acceleration, hardware zooming, a 64-bit graphics engine and direct conversion from the different colour palettes found in film sequences to those used on PCs."
     PC Review, Iss.47, September 1995


Found in MSI motherboard add-in, MS4415 and ExpertColor Laguna 5000.


Launched: ?
Bus: ?
Memory: ?

The CL-GD5480 was a 64-bit Alpine accelerator with 100 MHz SGRAM.