I understand the potential performance penalty!
Mind you, I would actually like to try running a *nix on this board. It'll need memory.
Would be interesting to know how the first 64MB of cached RAM is used in a 256MB configuration under Windows
nickles rust wrote on 2025-04-04, 22:41:I suppose "best" is a matter of opinion. I think the AMD K6-3+ is the best Socket 7 CPU. There is a lot of good info about the […]
I suppose "best" is a matter of opinion. I think the AMD K6-3+ is the best Socket 7 CPU. There is a lot of good info about them here on the forum.
It is the fastest, it is not very expensive, it is not chipzilla, it is speed/power adaptable in software, it is low power, it is a pretty color and smells nice, etc. The K6-2+ is nearly the same thing, and with some effort it can often be converted to a 3+. In older motherboards these low-voltage mobile CPUs can require BIOS updates or power supply updates to provide a lower (or even separate) core voltage. There are/were a variety of ways to accomplish this with different degrees of DIY or aftermarket support. There is a lot of good info about that here too. But maybe expedient is “best” and whatever you already have working is it.
I got one of these working in an old motherboard and I'm very pleased with it:
What does that interposer do? What are those two black rectangles for?
Plan your life wisely, you'll be dead before you know it.
luRaichu wrote on 2025-04-14, 18:16:Mind you, I would actually like to try running a *nix on this board. It'll need memory.
If so, you might want to buy a Cyrix MII.
It's Family 6 (i686, with CMOV), so you might be able to run modern Linuxes like Debian Bookworm or openSUSE Tumbleweed (but you might not be able to boot it with 256MB, as recent initramfs are very large).
古いマシンで新しいOS(Linux/NetBSD)を動かすのが好き。
Timezone : UTC+9
luRaichu wrote on 2025-04-14, 18:16:I understand the potential performance penalty!
Mind you, I would actually like to try running a *nix on this board. It'll need memory.
Would be interesting to know how the first 64MB of cached RAM is used in a 256MB configuration under Windows
I've been trying to find sources but pulling up blanks. What I recall is that DOS/Win9x tend to end up working in the uncached area where NT-based Windows - and Linux (and assumedly other*nixen) use all of it so at least benefit from the cache fhere present - but I may recall incorrectly.
One thing is clear: with NT and *nix you can - and probably will - use as much RAM as you can get, so given uncached RAM is still vastly faster than thrashing to HDD I'd agree you want to max RAM in this case.
feipoa wrote on 2025-04-24, 06:31:nickles rust wrote on 2025-04-04, 22:41:I suppose "best" is a matter of opinion. I think the AMD K6-3+ is the best Socket 7 CPU. There is a lot of good info about the […]
I suppose "best" is a matter of opinion. I think the AMD K6-3+ is the best Socket 7 CPU. There is a lot of good info about them here on the forum.
It is the fastest, it is not very expensive, it is not chipzilla, it is speed/power adaptable in software, it is low power, it is a pretty color and smells nice, etc. The K6-2+ is nearly the same thing, and with some effort it can often be converted to a 3+. In older motherboards these low-voltage mobile CPUs can require BIOS updates or power supply updates to provide a lower (or even separate) core voltage. There are/were a variety of ways to accomplish this with different degrees of DIY or aftermarket support. There is a lot of good info about that here too. But maybe expedient is “best” and whatever you already have working is it.
I got one of these working in an old motherboard and I'm very pleased with it:
What does that interposer do? What are those two black rectangles for?
I saw the original writeup for these on the 68kMLA trading post. They're newly made voltage converters that allow the AMD K6-2+ to work in a 3.3v only Socket 7/5. They're $100 each
kagura1050 wrote on 2025-04-24, 07:09:luRaichu wrote on 2025-04-14, 18:16:Mind you, I would actually like to try running a *nix on this board. It'll need memory.
If so, you might want to buy a Cyrix MII.
It's Family 6 (i686, with CMOV), so you might be able to run modern Linuxes like Debian Bookworm or openSUSE Tumbleweed (but you might not be able to boot it with 256MB, as recent initramfs are very large).
No. K6-2 is faster. NetBSD can use it fine & they have a lot of drivers for old PCI and ISA cards.
I installed T2 linux on a K6-3+ machine. I'm not very linux savvy but everything seems to work as expected. I think T2 may be one of the only current versions that doesn't need 10 cores, 3GHz and 8GB to compile and run "Hello world."
Tiny Core Linux and Gentoo Linux should work as well.
My 256MB stick of PC100 finally arrived today, from a US Armed Forces Pacific address. It came covered in some fine grey dust or powder which wasn't pictured on the listing. I cleaned the contacts with isopropyl alcohol and a cotton swab.
Turn on, boot up, jack in... That's not what happened. Power light lit, fans spin up, FSB set to 50MHz, but no beeps from PC speaker. Nothing. I even tried a known-good ISA video card, no output.
My power supply is good. 2.02 volts going to the K6-2 which I bought from MemoryMasters. All my jumpers are set right. Looks like I have a non-functioning motherboard on my hands!!
Maybe my ROM-BIOS is bad. Maybe it needs a recap. (there's one or two caps that're visibly starting to bulge but just barely so I thought it was okay?)
I once had this circa 2009 microATX PC which wouldn't turn on. It would spin up the fans, HDD and then they'd shut off after a second. I look at the board and almost all caps are visibly bursting. Worked fine after recap. Like I said maybe that's what's happening here. AT PSUs can't turn themselves off like ATX PSUs.
Also, on the MB-8500TTD, is the PC speaker meant to beep to indicate memory error, no memory, etc?
Does it do anything different with no RAM? I guess this is where one of those post cards might show something. Also, I had a board once that would appear completely dead without a good battery installed.
No yeah same behavior when I tested without RAM earlier. I did put in a battery.
I think the Award BIOS is meant to beep the PC speaker if RAM is not installed. I should've gotten a beep that time.
What POST diagnostic card should I buy?
Unless you have another system to verify that that DIMM works correctly I'd not immediately assume that it's your motherboard that's at fault here. Yes, it should generally beep with memory errors, but while there's only one way for something to work correctly, there's infinite ways of not working, including ones without beeps.
Looking back at your pic, I see the tag RAM socket (the PDIP-28 between the DIMM slots and the PLB cache chips) isn't populated. Is that still the case or did you just remove it for cleaning? If there's no SRAM chip in there that might also be part of the problem.
The TAG RAM is too slow for a K6-2 so that's why I removed it. But I did reinstall it yesterday with no effect.
dionb wrote on 2025-04-24, 08:40:luRaichu wrote on 2025-04-14, 18:16:I understand the potential performance penalty!
Mind you, I would actually like to try running a *nix on this board. It'll need memory.
Would be interesting to know how the first 64MB of cached RAM is used in a 256MB configuration under WindowsI've been trying to find sources but pulling up blanks. What I recall is that DOS/Win9x tend to end up working in the uncached area where NT-based Windows - and Linux (and assumedly other*nixen) use all of it so at least benefit from the cache fhere present - but I may recall incorrectly.
One thing is clear: with NT and *nix you can - and probably will - use as much RAM as you can get, so given uncached RAM is still vastly faster than thrashing to HDD I'd agree you want to max RAM in this case.
This is the kind of stuff OS2Museum or Old New Thing often covers, and it would be a great article, if you're out there...
Assuming Win95 allocates physical memory from the highest addresses downward (which, like you, I feel like I read but can't find a source today), that would cause the uncached memory to be used first.
There are reasons they might have wanted to do that. For example, reads or writes to the floppy controller need to use buffers below 16MB for ISA DMA. And because Win95 processes still need certain per-process DOS data structures allocated (see the book Unauthorized Windows 95), maybe it made sense to conserve memory below 1MB as well. A simple way to conserve such special "memory below some boundary" would be to give Windows processes memory from the top down.
By the way: from reading the XMS spec once, I read that before HIMEM.SYS existed, some drivers/TSRs that wanted to use extended memory would do so by hooking the interrupt to determine the amount of extended memory in the system and subtracting their allocation from whatever the previous handler returned. Yuck! But this may have caused a legacy of allocating extended memory from the top down.
Got this board to POST with two 128MB sticks of IBM branded PC133. Still no PC speaker sounds, and I know the speaker is good.
And then I bought a desktop case for this build.
Even the “for parts” ATI Rage II card is working as well.
In the BIOS configuration, I see many options to tweak DRAM operation. How should I make my memory run as fast as it can? Also would be nice to mod BIOS to disable memory check on startup. Can confirm feipoa’s recommendation to remove TAG RAM chip AND still have “external cache” enabled in BIOS config (will not boot with option disabled, bad programming).
Normally the numbers in the BIOS concerning memory which are smaller tend to yield faster memory throughput. I'm pretty sure at 500 MHz w/K6-3+ at 83 MHz FSB, I had to resort to EDO 72-pin SIMMs to get the system the fastest possible, yet still fully stable.
Plan your life wisely, you'll be dead before you know it.
