I now have 4 Cyrix builds:

486DLC/40+Cyrix Fasmath
Cx486DX2/80
MediaGX 266@300MHz
MII PR300

I never paid much attention to Cyrix back in 1990s except for their math coprocessors. All these years later it has been a very interesting journey getting each one these systems together and finding out just how important of a role Cyrix played back then. Their CPUs offered a great balance of price and performance. I only wished they could have hung in there longer before merging with National Semiconductor and then being bought out by VIA. The biggest surprise for me was the MediaGX. I never thought it would perform as well as it does. It is probably my favorite Cyrix build. I just want to give a big thumbs up to Cyrix and what fun it's been making these systems I now have a part of my retro collection:)

Has anyone ever come across any of the fabled mIII socket 7 cpus that were apparently never released? But were actually made in small quantity.

On the topic of the ill-fated Cyrix III "Joshua" core, I found the databook for it from chipsdb.org!

http://datasheets.chipdb.org/VIA/Joshua/cyrix3db.pdf

I think they were actually for Socket370. I've only ever seen pictures of them.
There was supposed to be a socket7 version, but I'm pretty sure that one didn't make it past engineering samples, if it even got that far.

mwdmeyer wrote on 2021-03-28, 07:30:

I was impressed with the 6x86MX/MII chips. The 6x86 (PR200L) not so much

That was pretty much my feeling as well.

Anonymous Coward wrote on 2021-12-12, 03:53:

I think they were actually for Socket370. I've only ever seen pictures of them.
There was supposed to be a socket7 version, but I'm pretty sure that one didn't make it past engineering samples, if it even got that far.

I’m really wondering if it’s possible to track down someone who might know for sure, maybe one of the engineers is floating around the internet somewhere.

feipoa wrote on 2021-12-12, 04:51:

mwdmeyer wrote on 2021-03-28, 07:30:

I was impressed with the 6x86MX/MII chips. The 6x86 (PR200L) not so much

That was pretty much my feeling as well.

If you were using it for office tasks 6x86 was also mighty impressive.

Just.. dont run Quake.

The MX/MII had an improved FPU so it wasn't even all that bad on Quake.

The Joshua thing, I never understood that, samples seemed to be saying it was a bit hot but was performing in the ballpark of celerons, saw reviews where it wasn't that bad... then they went with the winchip design that had the IPC of.... a winchip, and not even the 2B... it was cooler, frequency scaled... but seriously that part HAD to run at 900 before it was performing like the 500Mhz Joshua. Ppl talk up the 1.2Ghz Ezras, but to me, it's like it's a netburst on socket 370, all empty cycles, no actual grunt.

https://web.archive.org/web/20010419022037/ht … 0424/index.html I found some old benchmarks of the Joshua core VIA Cyrix III! This came before their sudden switch from the Joshua core to the Samuel core. Either way, it was still kinda blown out of the water by a Celeron.

themajortechie wrote on 2021-12-15, 05:16:

https://web.archive.org/web/20010419022037/ht … 0424/index.html I found some old benchmarks of the Joshua core VIA Cyrix III! This came before their sudden switch from the Joshua core to the Samuel core. Either way, it was still kinda blown out of the water by a Celeron.

Wonder how it did mhz to mhz

The pr number was kinda unrealistic

For me, no definition of "blown out of the water" includes situations where the comparison at only the PR rating beat something on three tests, and personally, given the error margins in benchmarking, I'd call it a dead heat in three more of them. Comparison at equal clocks would completely flip the results there, with celeron only edging a win in 3 tests. Then all the quakes may as well have been written by intel's marketing department, they're so relentlessly intel optimised, there's tens of thousands of games that aren't quake. You'd probably get equal quake performance per dollar anyway, as Cyrix would normally price around 2 or 3 speed steps lower than PR equivalent Intel, so you'd be looking at a PR500 or a celly 366. So yah, I'd say Joshua was decently competitive with celeron.

I have a TI(Cyrix) 486DLC-40 on an MX 305 board, and a Cyrix 5x86-100. The 5x86-100's certainly a large step up from a Cyrix 486DX4-100, I'll say that much.
The 5x86 ALU benchmarks on my Shuttle HOT-433 to within a stone's throw of a Pentium 90 on an ancient Socket 5 board made by Asus with an SiS 503 chipset. PCI/I-P54SP4 I believe it is.

As the two systems were so similar in ALU performance (and indeed, they felt practically identical in experience), I decided to convert the 5x86 build into something a little different... a UMC U5SX-40 build! I like having well-defined and tangible 'steps' in performance between generations, and the 5x86 and P-90 builds would have been pretty redundant with each other IMO.

Not sure what I have in store for the 5x86-100 CPU... for now it sleeps.

Arise from your slumbers ye adepts of the lone star CPU. Thine fabless glory of Richardson gloweth still in the firmament ....

Cyrix/ST/IBM Aiming for the stars!

So yeah, there's a new Cyrix overclocking and benching thread in case you missed it.

BitWrangler wrote on 2022-03-11, 22:47:

Arise from your slumbers ye adepts of the lone star CPU. Thine fabless glory of Richardson gloweth still in the firmament ....

Cyrix/ST/IBM Aiming for the stars!

So yeah, there's a new Cyrix overclocking and benching thread in case you missed it.

Woohoo!! So far I am wining I think? (Prob not for long I suspect 🤣)

https://www.ebay.com/itm/393986256415

Some 2.2v cpus. (Seem to be same core as 433gp)

Brickpad wrote on 2016-07-08, 05:35:

Bought an ECS UC-4913 v1.1 socket 3 board with a Cyrix Cx486S-40 FasCache CPU. It's rather peculiar as the Cyrix is attached to what appears to be a socket 3 voltage adapter. You can't see it from the seller's photo unfortunately. Both board and CPU should be running at 5V, so I don't know what the adapter is for?

Image is from the seller's listing.

Just bought a UC4913 with a Cyrix Cx486S-40, also with a peculiar interposer. Thought it might've been your exact motherboard until I saw mine was V1.0.
Could this interposer be a Cx487S FPU attachment?
(From seller's listing)

NScaleTransitModels wrote on 2022-07-08, 08:00:

Just bought a UC4913 with a Cyrix Cx486S-40, also with a peculiar interposer. Thought it might've been your exact motherboard un […]
Show full quote

Brickpad wrote on 2016-07-08, 05:35:

Bought an ECS UC-4913 v1.1 socket 3 board with a Cyrix Cx486S-40 FasCache CPU. It's rather peculiar as the Cyrix is attached to what appears to be a socket 3 voltage adapter. You can't see it from the seller's photo unfortunately. Both board and CPU should be running at 5V, so I don't know what the adapter is for?

Image is from the seller's listing.

Just bought a UC4913 with a Cyrix Cx486S-40, also with a peculiar interposer. Thought it might've been your exact motherboard until I saw mine was V1.0.
Could this interposer be a Cx487S FPU attachment?
(From seller's listing)
(uc4913) s-l1600.jpg

Yeah, there's a Cyrix CX487S QFP underneath.

NScaleTransitModels wrote on 2022-07-08, 08:00:

Just bought a UC4913 with a Cyrix Cx486S-40, also with a peculiar interposer. Thought it might've been your exact motherboard un […]
Show full quote

Brickpad wrote on 2016-07-08, 05:35:

Bought an ECS UC-4913 v1.1 socket 3 board with a Cyrix Cx486S-40 FasCache CPU. It's rather peculiar as the Cyrix is attached to what appears to be a socket 3 voltage adapter. You can't see it from the seller's photo unfortunately. Both board and CPU should be running at 5V, so I don't know what the adapter is for?

Image is from the seller's listing.

Just bought a UC4913 with a Cyrix Cx486S-40, also with a peculiar interposer. Thought it might've been your exact motherboard until I saw mine was V1.0.
Could this interposer be a Cx487S FPU attachment?
(From seller's listing)
(uc4913) s-l1600.jpg

Yes. I struggled finding a socket 3 which worked properly with one of these units.

Anyone have any contacts that they can talk to to see about talking to a old cyrix engineer to see what happened with the jedi core cpus? Did any make it to prototype? Did they snag any?

I had made a brief thread on this but thought I might post here as well.

Basic Specs of my MII build:
PC Chips M571 motherboard
All fastest ram/cache options in BIOS
Cyrix MII 266GP 2.0v 75x4@300MHZ
1x128MB Cl2 SDRAM PC100
ATI Rage XL 8MB PCI video
ESS AudioDrive 1868 ISA sound card
VIA USB 2.0 PCI (USB 2.o disabled, no performance penalty)
WD 20GB HDD UDMA2
Basic 32x CD-ROM (not sure of the brand)
No-name baby-AT case. Black in color, to be different like the rest of the build
Windows 98SE, DX7.0 No unofficial patches other than NUSB

Phil's DOSbench:
3dBench (slow PC) 223.4
3dbench (fast PC) 50.0
Chris 3dBench (slow PC) 128.8
Chris 3dbench (fast PC) 27.0
PC Player Benchmark 320x200: 69.2
PC Player 640x480: 14.3
Doom Minimum: 2134 in 255
Doom Max: 2134 in 1354
Quake Low: 44fps
Quake High: 9.3
Sysinfo: 139.9
Topbench: 407
Speedsys: CPU score of: 199.99 from Windows 98 command prompt. Hangs at read MSRs when ran from DOS
Landmark: 3585 CPU/3957 FPU

A few Windows Benchmarks:

3dmark 99 Default benchmark (Rage XL):
817 3dmarks, 1341 CPU 3dmarks
3dmark 99 Default benchmark (Voodoo 3):
972 3dmarks, 1319 CPU 3dmarks

3dmark 2000 Rage XL: 128
Final Reality: 1.82

If anyone would like me to run anything else, please let me know.

EDIT: Forgot to add Quake2 640x480 demo.dm2 14.8fps