GCT MediaGX Boards


GCT makes many different Cyrix MediaGX integrated motherboards. Their product offerings tend to lag behind Cyrix's current product by roughly six to eight months. Their low power consumption and compact integration of just about every PC component make them extremely handy boards for single-board computer projects. The 266 MHz version of this board is also available in the Micro-ATX form factor -- this practically eliminates the ribbon cable clutter characteristic of baby-AT systems.

Integrated Hardware

Cyrix MediaGX systems are great for all-in-one-piece projects. The CPU is always sold with the motherboard because it must be matched with the appropriate companion chip which is a permanently mounted BGA package. The CPU and companion supply the system with PCI video and ISA audio along with the EIDE and other peripherals. Cyrix is reportedly planning to integrate the system even further to a one-chip solution. Currently, GCT tends to supplant the built-in MGX audio with C-Media sound chipsets which makes them a better value than the other MGX boards on the market since the MediaGX sound is very long in the tooth. The 233 MHz version uses the Cx5520 companion which gives regular EIDE, no USB, and no TV-OUT. Newer boards use the Cx5530 companion which gives you PCI audio and busmastering UDMA/33, USB, and TV-OUT.


I have so far dealt with the GCT 7520 (ST-MGXm) board which is a 233 MHz MMX system with the Cx5520 companion and a CM8330A sound chipset. It has a blank space where an EISA card slot would go and has other spaces for missing components. The newer boards with the Cx5530 companion have much better features.

Comments and Experiences

This board has a single ISA slot and two PCI slots. You can add two PCI cards fairly simply but there just isn't much room for expansion if you have to add an ISA card with another PCI card. The fact that the CM8330A forces you to have both a SB16 and a Windows Sound System device severely limits your IRQ selections since those IRQ's cannot be shared. This is similar to the CM8330 on the TXPRO II but without the 3D Audio and Wavetable features. See my description of the PCChips TXPRO II system elsewhere on this site for more details on this family of integrated audio chipsets.

This board is now being sold for about $90 with the CPU. It's a good simple system -- especially as a Unix server or a place to park all your old storage peripherals. The 266 MHz and upcoming 300 MHz boards with the Cx5530 and higher companion chips will make this system even better. Ensure your dealer sells the CPU and the motherboard as one unit.

Be sure to install the video and sound drivers on this board! Like many other video cards, the video subsystem absolutely requires the special MediaGX accelerated drivers. The "standard VGA" emulation is unworkable. If you plan to use this system with operating systems other than Windows make sure you can find accelerated drivers for MediaGX or you will be sorely disappointed in its default video performance. The same could be said of the audio system.


Wikipedia articles (includes my contributions):
Wikipedia: MediaGX
Wikipedia: Geode (Processor)
Wikipedia: Cyrix
GCT Tech:

Computer Parts Only:


This information is constantly being updated. Please check back often or contribute your own comments at the contact link at the bottom of this page.