You have a Cx486 Fascache? It's not a 486S, but one with a mathco? It must be pretty uncommon.

*edit* I just found this snippet on google groups:

"The Cx486S has a 2k internal cache. When stacked on top of (literally) a
487S FPU, they call it a Cx486D which of course also has a 2k cache."

That's very interesting. I guess it's like how a 486DRu chip is a regular DLC on a clock doubler module.

I have one of these on the way with the Cx487s PGA adapter, https://en.wikipedia.org/wiki/Cyrix_Cx486#/me … yrix_Cx486S.jpg

I haven't seen a Cx486D. Got pics? I'm always amazed at all the oddball Cyrix configurations.

feipoa wrote:

I have one of these on the way with the Cx487s PGA adapter, https://en.wikipedia.org/wiki/Cyrix_Cx486#/me … yrix_Cx486S.jpg

I haven't seen a Cx486D. Got pics? I'm always amazed at all the oddball Cyrix configurations.

See above. The 486D is not a stand alone product. It's a comination of the 486S and the 487S module. So what you bought IS a 486D.

Ahh, except that the pieces I bought did not come together, that is, they were separate. Sounds like I will be "assembling" a Cx486D.

I'm really curious about the FPU results with this combo. I would think the performance should be similar to a 387, but at least according to the newgroups posts I saw, it's said the FPU performance is actually quite good.

So am I. I'd certainly like to compare the Cx486 FasCache + Cx487S with the Cx486DX-40. I'm hoping that the PGA interposer board will also work with PGA168 version of the TI486SXL2 and the UMC U5S. For those reading this who may be confused with what I'm talking about, here's a photo of the unit, taken from http://www.cpu-world.com/forum/viewtopic.php?t=29597

@feipoa: No, not saying that the FasCache uses write-through. Just that Cyrix's implementation of L1 seems a bit odd, that while the cache itself is not particularly fast, the off-cache accesses are definitely a little faster than usual. Perhaps they had cheap laptop computers without L2 cache in mind when making their post-386 socket 486s?

It is amazing how much of this thread I have forgotten in less than a year. I know I've tested the Cx486S by now and I think I benchmarked it. I suspect the discussion is continued here, TI 486SXL and 486SXL2 PGA168 on socket 3 motherboards

Finding a board which works with the Cx486S FasCache was non-trivial.