I'm dealing with this on a PC Chips M520 and an Intel Advanced / EV motherboard. Both don't like my ASUS 512kB COASt module.

Same here on my ECS P5VX-A. I have 2x 256KB modules. Machine boots, but neither cache module is recognized.

creid2 wrote on 2022-01-23, 00:01:

Hi - I'm hoping someone has some good advice about COASt module compatibility on an old Shuttle HOT-553 socket 7 build. Motherbo […]
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Hi - I'm hoping someone has some good advice about COASt module compatibility on an old Shuttle HOT-553 socket 7 build.
Motherboard comes with 256k L2 cache on board, and has a "CLEP" socket (manual calls it this) for a 256k upgrade. Went to ebay to find one of these COASt modules, score, change appropriate jumpers, and the system hangs on boot. Absolutely nothing but black screen. This is the Samsung (SEC) one in the photo.
OK- I am totally aware of the risks one takes buying old stuff from ebay. Purchase a second, pop it in, and it POSTS! Things are looking good- but on the POST screen, it indicates only 256k of L2 cache! This is the ISSI one in the photo.
Being a dummy, I go for a third. This one I find actually says "FOR 430FX/HX" (the shuttle hot-553 is i430HX) AND it has jumpers on it, which I imagine change timing or something like that to make it compatible under variable circumstances. Pop it in, it POSTS! But the POST screen indicates "None" under Cache Memory. This is the Galvantech one in the photo.
Now, I've tried messing with the jumpers on the COASt module. I get all different kinds of weirdness under different jumper settings, from hanging on POST, to getting 256k back on POST, to black screens. I cannot find any manual for the jumper settings on the module.

I upgraded the BIOS to the latest version (that I can find anyway, 12/1997). I tried 256MB EDO ram and 64MB FPM ram. I've even tried not changing the jumpers on the motherboard (for the Cache addition). Nothing seems to work.

OK peeps, what are your thoughts? Am I so unlucky to have scored three bum COASTs? Are there VERY SENSITIVE compatibilities that I am missing? To note, the soldered cache chips are tmTech variety, and none of the COASt modules have chips of this brand.

A number of the Shuttle boards, including the HOT-553, take a specific type of COASt module which has no TAG chip - you can see more info in this thread... Shuttle HOT-557 Pipeline Burst Cache type?

Coast compatibility is a huge nightmare there are even horror stories of some modules actually frying mobos because of non standard pinouts that some mobos used.

Best to try and find someone with a working config and buy exactly what they have or at least find a google pic.

PC Hoarder Patrol wrote on 2022-01-23, 00:31:

creid2 wrote on 2022-01-23, 00:01:

Hi - I'm hoping someone has some good advice about COASt module compatibility on an old Shuttle HOT-553 socket 7 build. Motherbo […]
Show full quote

Hi - I'm hoping someone has some good advice about COASt module compatibility on an old Shuttle HOT-553 socket 7 build.
Motherboard comes with 256k L2 cache on board, and has a "CLEP" socket (manual calls it this) for a 256k upgrade. Went to ebay to find one of these COASt modules, score, change appropriate jumpers, and the system hangs on boot. Absolutely nothing but black screen. This is the Samsung (SEC) one in the photo.
OK- I am totally aware of the risks one takes buying old stuff from ebay. Purchase a second, pop it in, and it POSTS! Things are looking good- but on the POST screen, it indicates only 256k of L2 cache! This is the ISSI one in the photo.
Being a dummy, I go for a third. This one I find actually says "FOR 430FX/HX" (the shuttle hot-553 is i430HX) AND it has jumpers on it, which I imagine change timing or something like that to make it compatible under variable circumstances. Pop it in, it POSTS! But the POST screen indicates "None" under Cache Memory. This is the Galvantech one in the photo.
Now, I've tried messing with the jumpers on the COASt module. I get all different kinds of weirdness under different jumper settings, from hanging on POST, to getting 256k back on POST, to black screens. I cannot find any manual for the jumper settings on the module.

I upgraded the BIOS to the latest version (that I can find anyway, 12/1997). I tried 256MB EDO ram and 64MB FPM ram. I've even tried not changing the jumpers on the motherboard (for the Cache addition). Nothing seems to work.

OK peeps, what are your thoughts? Am I so unlucky to have scored three bum COASTs? Are there VERY SENSITIVE compatibilities that I am missing? To note, the soldered cache chips are tmTech variety, and none of the COASt modules have chips of this brand.

A number of the Shuttle boards, including the HOT-553, take a specific type of COASt module which has no TAG chip - you can see more info in this thread... Shuttle HOT-557 Pipeline Burst Cache type?

Thanks Hoarder! I will be on look out for one of those.
I wonder if you could just de-solder the TAG ram? Prob not...

As a quick check, of course, removing the TAG ram DIP from the motherboard did not help.

It's one of those things where everyone seemed to think that the standard was so important that they ought to have their own version of it.

Personally, I think COAST ought to stand for Cache Only Apocryphal on the Stupid Things... you can see it, but getting it working on a given board is a crap shoot.

BitWrangler wrote on 2022-01-23, 01:47:

It's one of those things where everyone seemed to think that the standard was so important that they ought to have their own version of it.

Personally, I think COAST ought to stand for Cache Only Apocryphal on the Stupid Things... you can see it, but getting it working on a given board is a crap shoot.

I hear ya, Bitwrangler, I think I've wasted more money over the years trying to upgrade cache on computers than on anything else. (note: "wasted" is not the same as "spent")

If you have a mainboard that already has 256K L2 cache and a TAG-RAM onboard, the additional COAST module needs to have

1. additional 256K L2 cache
2. an additional TAG-RAM (to enlarge the cacheable area to the full 512MB of RAM)
3. pin 6 counted from the right (plus 2 more pins) must be conneted to the TAG-chip.
4. The pinout and design opf the COAST socket and the cache-module must match
5. (additional requirements of the COAST versions (that provide backward compatibility) must be met.

From the 3 modules in the picture only the Samsung stick has pin 6 connected.

The point is the onboard TAG-RAM and the one on the COAST module need to interact here. Thats only possible if the module is designed for that. Many modules were made for operating as a standalone.

I tried to elaborate some of the details here:
The legendary HX chipset

I was under the impression that most boards with COAST slots would use either the onboard chips OR the COAST module; not add both of them together.

Another (previous) take on the topic - https://www.vcfed.org/forum/forum/genres/pent … 0197#post520197

cyclone3d wrote on 2022-01-23, 06:46:

I was under the impression that most boards with COAST slots would use either the onboard chips OR the COAST module; not add both of them together.

That´s true for FX (or similar) mainbords with onboard DIL sockets. Many / most HX boards could be upgraded from 256K to 512K with a 256K stick, but you needed the right module and the jumpering had to be correct.
The legendary ASUS P55T2P4 accepts nearly every COAST stick, it´s amazing. But some boards are picky, some even need a proprietary stick.

If the HOT-557 really demands a stick with NO TAG-RAM, you might as well forget about upgrading L2 cache because due to the HX chipset properties you would be limited to 64 MB cacheable area. This is really a design flaw on Shuttle´s side.

majestyk wrote on 2022-01-23, 07:09:

That´s true for FX (or similar) mainbords with onboard DIL sockets. Many / most HX boards could be upgraded from 256K to 512K wi […]
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cyclone3d wrote on 2022-01-23, 06:46:

I was under the impression that most boards with COAST slots would use either the onboard chips OR the COAST module; not add both of them together.

That´s true for FX (or similar) mainbords with onboard DIL sockets. Many / most HX boards could be upgraded from 256K to 512K with a 256K stick, but you needed the right module and the jumpering had to be correct.
The legendary ASUS P55T2P4 accepts nearly every COAST stick, it´s amazing. But some boards are picky, some even need a proprietary stick.

If the HOT-557 really demands a stick with NO TAG-RAM, you might as well forget about upgrading L2 cache because due to the HX chipset properties you would be limited to 64 MB cacheable area. This is really a design flaw on Shuttle´s side.

Further information:
-Hx supports up to 512mb cached ram
-Tx supports up to 64 mb cached ram
-Max ram on hx is 512mb
-Max ram on tx is 256mb
-I believe many hx boards that support 512 mb cached had two tag chips to accomplish this but it’s really only a specific amount of tag bits to do this that are required so if you have that many bits with one chip then, there you are. I think you also needed the max l2 cache supported by the chipset to also be installed which was 512k for hx and tx.
-Catchable area is no longer a concern if you use a k6+ cpu
-Using more ram than what is cached is possible but not more than what the chipset supports.

At OP: can we get high res pics of your board?

Exactly, there´s no way for a HX board to have a cacheable area of 512 MB with just one TAG-chip.
Some (few) boards have 512K onboard L2 cache and just one TAG chip - this is of course a rip-off.
All 28-pin TAG chips at that time had only 8-bit TAG-BUS width, for a cacheable area of more than 64MB you need a 10-bit bus-width = 2 chips.
Later in the super socket 7 era there were designs with enlarged 32-pin TAG chips so one TAG chip would provide the bus-width for 2MB L2 cache and more.

Intel´s 430FX is limited to 128MB RAM and a cacheable area of 64MB (just like TX) so it´s no problem when COAST and DIL cache can´t be used at the same time..
But since COAST cache can be run in (faster) pipeline-burst mode it makes sense to remove the DIL chips and insert a 256K COASt stick instead.

majestyk wrote on 2022-01-23, 07:48:

Exactly, there´s no way for a HX board to have a cacheable area of 512 MB with just one TAG-chip.

Ah, but there is a way…

Sphere478 wrote on 2022-01-23, 08:06:

majestyk wrote on 2022-01-23, 07:48:

Exactly, there´s no way for a HX board to have a cacheable area of 512 MB with just one TAG-chip.

Ah, but there is a way…886735CA-D688-4F65-9470-402BFC928213.jpeg

Technically there isn't. The motherboard will still only cache 64MB but since its cache has been demoted to L3 and the CPU's internal L2 can cache 4GB (afaik) the performance hit will be much less.