Hello! I'm working on an article about AMD Hammer series and the amount on info keeps growing crazy.
Among other things I tried to sort early ES CPUs and found about yours.
If it's not a big problem, could you share a copy of BIOS from your SOLO 5 board and a CPU-Z txt report?
Would be nice to know what makes the system identify CPUs as Athlon HX.
And maybe you have some other interesting info regarding AMD reference boards and ES CPUs.
Thank you in advance!
Looking forward to your AMD Hammer article!
I have booted up the motherboard and downloaded a fresh copy of CPU-Z. You can download the exported report and BIOS (both .TXT files) here: BIOS276.ZIP. I tried a couple of programs running on Windows to export the BIOS as a binary but didn't succeed. Will try DOS based utilities later when I have a bootable diskette and drive sorted 
.
The Athlon HX name is displayed in CPU-Z so that's the name I've always used in my collection for this specific CPU. You can find references online to Athlon HX, for example on this github for cpuinfo.py.
Do you have a copy of the HammerOverview.pdf file (AMD Developer Symposium 2002)? It mentions the AMD Stretto which is the dual socket 754 motherboard. Apparently AMD had ideas for 1 and 2-way S754 systems and 4-way S940 systems. Later all 2-way systems became S940.
Thank you for such a quick answer!
I assume you've tried Winflash from Windows to save your BIOS? IIRC, it doesn't work on all systems so might work for you.
Athlons (Athlon 64s in our case) don't have a name of their own. So CPU-Z shows the name that is programmed by the BIOS. And it's up to the BIOS to properly identify and label the CPU during booting. That's why I wanted to take a look in it. You can program any name of your own and CPU-Z will show it.
I'll check if I have this presentation but yes, I've heard and found a photo of Stretto, Melody and several other boards. Looking for photos of Solo besides 2 and 5.
So using my trusty Am386DX I created a bootable diskette and transferred AWDFLASH and the .BIN file to my FTP-server. I have a proper .BIN file ready now. I've added it to the BIOS276.ZIP file so if you re-download it you'll get the BIOS-file (if you still get the old file, please clear your cache or use a Private/Incognito tab).
Using Modbin you can see there is a hidden debug-menu with all kinds of fancy Hammer/HyperTransport related settings .
As mentioned on the page thandor.net - Athlon HX 1400 I've tried running regular Athlon64 in the AMD Solo5 motherboard and tried running the engineering sample CPU in a regular S754 board. It did not work (and didn't fry/break anything either, I remember reading someone saying it would damage the hardware but it doesn't, at least not in my case). In the meantime I obtained a pre-release model of an Athlon64 2800+ (CPU-World - ADAAA2800ACN5) dated 51th week of 2002 but it doesn't work in the AMD Solo5 either. Apparently AMD changed something in these CPU's during the development.
That is some excellent stuff you've told! I'll have an in-depth look into the BIOS, many thanks.
It's also very nice to know that CN5 doesn't work either, it's the best chance we had. It's B0 stepping. Mine is 0248.
Have you checked what DDR speeds does your HX 1400 work with? I suppose DDR266/333? During Computex 2002 vendors showed there 754 boards having support of DDR266/333. During these days B0 wasn't available yet so I suppose A0/A1 were DDR333 at top (probably DDR200/266 for A0 due to 800MHz frequency and dividers).
P.S. checked the BIOS - yes, lots if things there, DDR333 maximum. And a bunch of settings we see only on DFI Lanparty series of boards.
According to CPU-Z it runs at CPU/9 == 155MHz. According to the system information in the BIOS it runs at 166MHz CL2.5. I have two Hynix 166MHz (DDR333, PC2700) modules installed.
You mentioned other photo's besides Solo 2 and Solo 5. There is a Solo 6 photo on HWUpgade.it. You can see the PCB# 1000126-006 on the motherboard. My motherboard has -005 and the AMD Solo 2 motherboard shown by AnandTech (which the Intel-melody in musical notes) has -002.
Thank you! I've found info (in Opteron datasheet) that DDR400 support appeared only from C0 stepping so our CN5 are DDR333 too. And yes, 155MHz seems to be the true value.
Interesting thing is that the article on HWUpgrage.it shows photos of Solo 6 but the preview seems to show Solo 5 (the only green Solo as I've learned so far). And I couldn't find any other source about that presentation (that took part during SMAU 2002 in Milan).
Since I had the motherboard at hand I’ve made new photo’s. You can find them on thandor.net - Athlon HX 1400.
On CPU-World someone has a Solo 7 and Solo 9 motherboard for trade. I’ve asked him for pictures. See this link.