Cyrix Media GXm-300GP 2.9V. Real or fake?

[Marcin]

After your tests results and additional fact about that I found exactly same piece from chinese seller then I change my opinion. It is well made fake chip. About your questions about price there is no big interest for around 30 dollars so I think it is max price for fake one.

[feipoa]

Where do you see another GXm-300 for sale? Could you provide the photos?

I am neither convinced it is fake, nor that it is real. There are some caveats with using the GX1-300 at 300 MHz, like it needs less RAM for stability compared to 266 MHz operation. This implies to me that the system as a whole has reached its design limit with 300 MHz. So there may be some aspect with the GXm compared to the GX1 that doesn't work well at 300 MHz on this particular motherboard. The results demonstrated thus fare are not conclusive.

The GXm at 300 MHz at least boots to DOS at 300 MHz and will run simple benchmarks. If I recall right, the 266 MHz GXm chips won't even boot at 300 MHz.

EDIT: I should point out the the motherboard documentation states support up to 266 MHz, not 300 MHz.

If you think back to some slot 1 PIII systems, or slot A athlon systems, I have a slot 1 system which runs great at 850 MHz, but is not entirely stable at 1 GHz. Same rings true for 1 GHz slot A systems.

[cvandijk]

The seller where you bought yours has another one.

However, the font on the back looks different:

[feipoa]

Interesting. He's letting them out one at a time to maintain purchase value. I've seen different general formats on the back of Cyrix chips, so not sure what we can draw from that.

Anyone else have a GXm board who can run the GXm-300?

I'll see if I have a 32 MB SDRAM DIMM to test the GXm at 300 MHz. For DIMMs less than 64 MB, I think I only have an EDO DIMM.

[feipoa]

Looks like someone just bought the chip. Someone from here? Hopefully whoever bought it can test it and compare notes.

It took me about 2 hours to get the pins on mine straight enough to enter the ZIF without force.

[feipoa]

Brief update to this thread: I sourced another GX1-300P chip with white lettering (attached). To give an idea for how tight the timing must be on the GXm and motherboard at 300 MHz, the white lettered chip would not run Windows 98SE with 192 MB installed, while the purple lettered chip would. The white lettered chip could only handle 300 MHz if up to 64 MB was installed. I suspect a similar scenario plays out with the GXm-300 chip. Perhaps I should have bought the other GXm-300 chip for testing. Did someone here buy it and has a MediaGX motherboard?

Does anyone know the datecodes on the back of my purple and white GX1 chips? I'm wondering which is newer.

[CPUShack]

V3SKA013AB
2000 Week 13

[feipoa]

OK, so the one with purple lettering from page 2 of this thread, V85KA127AG, is 2001 week 27? That's quite a bit newer.

[CPUShack]