• Please review our updated Terms and Rules here

Cyrix MediaGX build

jasa1063

Experienced Member
Joined
Jan 5, 2015
Messages
386
Location
Minnesota, USA
I was looking into building a Cyrix 5x86 system, but then decided on a Cyrix MediaGX system since this has a Cyrix 5x86 core. I thought this would be a much more interesting build. The biggest obstacle is finding a motherboard. I saw a video on this topic on the CPU Galaxy YouTube channel and he had a link to a seller on eBay. I ordered a motherboard, CPU and accessories. Here are the system specs:

ECS P5GX-M motherboard
Geode GXm-266P CPU @2.9v overclocked to 300MHz (Same as a MediaGX just sold by National Semiconductor after buying Cyrix)
256MB (2x128MB) PC100 SDRAM
3Com Etherlink III network card
TopView ET6000 4MB video card
8GB CompactFlash with a CF to IDE adapter
1.44MB 3.5" floppy drive
16x DVD
Windows 98 SE with Unofficial Service Pack 3

I opted not to use the onboard video as this made overclocking easier and tighter memory timings. I did end up using the onboard SB16 audio. The next issue to resolve was finding a way to tweak the MediaGX register settings. Thanks to this post on vogons.org, I was able figure out how to use CTCHIP34 to tweak the MediaGX CPU including enabling Branch Prediciton. I already posted some results in that thread.

https://www.vogons.org/viewtopic.php?f=46&t=45756&p=469004&hilit=mediagx register#p469004

I have CTCHIP34 in my AUTOEXEC.BAT with the following parameters:

CTCHIP34 cx586 /20:=7
CTCHIP34 cx586 /0e8:=0f8

I have no stability issues, Here the results of some DOS benchmarks.

No tweaks applied:

SSTIMG01.jpg

Speedsys v4.78 visual results

3DBench 1.0c - 156.6 FPS
Chris's 3D Benchmark - 320x200 - 124.3 FPS
Chris's 3D Benchmark - 640x480 - 35.7 FPS
PC Player - 320x200 - 48.7 FPS
PC Player - 640x480 - 19.1 FPS
Doom - Max Details - 86.54 FPS
Quake - 320x200 - 35.2 FPS
Quake - 640x480 - 13.7 FPS
Norton SI 8.0 = 793.9
Topbench 40a - 686
SpeedSys 4.78 CPU Performance Index - 151.09

Tweaks applied:

SSTIMG02.jpg

Speedsys v4.78 visual results

3DBench 1.0c - 162.3 FPS
Chris's 3D Benchmark - 320x200 - 128.9 FPS
Chris's 3D Benchmark - 640x480 - 35.7 FPS
PC Player - 320x200 - 50.2 FPS
PC Player - 640x480 - 19.7 FPS
Doom - Max Details - 89.02 FPS
Quake - 320x200 - 39.8 FPS
Quake - 640x480 - 15.6 FPS
Norton SI 8.0 - 1020.6
Topbench 40a - 690
SpeedSys 4.78 CPU Peformance Index - 179.82

Overall this has been a fun build. It's basically like having a 486 system on steroids:)

IMG_0108.JPG

Computer front view

IMG_0110.JPG
Windows 98 SE with Cpu-Z info
 
Nice build.

I have one of those AMD 50x15 PICs that has a 400 MHz Geode GX in it and it's basically still a 486 on steroids. I never did try the utility to enable disabled features on it though. As it comes from the factory, it's locked down to Windows CE, you have to use an exploit to get a command prompt and flash a custom unlocked BIOS to it so it can boot other operating systems. Not at all expandable though, the only things you can change are the hard drive and DDR SODIMM memory module.
 
Back
Top