Well, if your willing to settle for 12ns...

https://www.mouser.com/ProductDetail/ID ... fqkw%3d%3d

for the record, 12ns is rated for 83.3mhz, plenty fast for a 486.

That'll do, thanks

Interesting to see these on Mouser. If anyone has ordered these, could you provide a photo (top and bottom)?

feipoa wrote:

Interesting to see these on Mouser. If anyone has ordered these, could you provide a photo (top and bottom)?

I'll have to dig around, I've bought some of these before off mouse in the last 5 or so years.
what do you want photos for, they are just your basic 300mil/7.62mm skinny 28pin dip.

I want to see if they have the stereotypical Chinese counterfeit look to the text - faded brown, no markings on the bottom, perhaps a somewhat glossy look to the bottom (not always the case). Sometimes the font on the Chinese rebranded pieces looks off.

I've been looking for genuine looking 10 and 12 ns SRAM for some time.

debs3759 wrote:

I'm upgrading both of my Asus PVI-486SP3 motherboards to max out the cache and RAM. I have sources for 64MB FPM RAM and 128Kx8 10ns cache chips, but can't find 10ns 28-pin 32Kx8 chips for the tag. Can anyone point me in the right direction? Any supplier that doesn't charge an arm and a leg to ship to the UK will be good.

I also have EEPROMs to upgrade the BIOS on the older (v 1.22) board. Will be hot flashing in the v1.8 board.

TIA

Do you run that board at 40 MHz FSB?
Do you get a stable 2-1-1-1 timing?
My board runs this timing stable at 40 MHz with 256 KB in 2 banks, 512 KB in 1 bank is only stable up to 33 MHz 🙁
(Tag RAM is always the same 15 ns module)

Useless information: This board supports a maximum of 192 MB RAM. However, not all is cacheable.

Disruptor wrote:

My board runs this timing stable at 40 MHz with 256 KB in 2 banks, 512 KB in 1 bank is only stable up to 33 MHz 🙁

That is very common and is why I recommend only using double-banked cache when the FSB is 40 MHz or higher. In fact, I don't think I've come across any PCI socket 3 boards which run 512K (single bank) stable when the FSB = 40 MHz and the timings are fully optimal. I'd far rather run 256K double-banked with tight timings than 512K single-banked with slower timings. 256K will cache 64 MB of RAM in write-through mode. Most people consider 32 or 64 MB an acceptable upper limit for RAM on socket 3 boards.

feipoa wrote:

I want to see if they have the stereotypical Chinese counterfeit look to the text - faded brown, no markings on the bottom, perhaps a somewhat glossy look to the bottom (not always the case). Sometimes the font on the Chinese rebranded pieces looks off.

I've been looking for genuine looking 10 and 12 ns SRAM for some time.

ugh, do you understand mouser is one of the biggest electronic suppliers in the business who deals directly with the companies involved, they are not ebay you know.

BloodyCactus wrote:

ugh, do you understand mouser is one of the biggest electronic suppliers in the business who deals directly with the companies involved, they are not ebay you know.

I'm like 95% sure feipoa wants to compare legit parts from ouser to possible fakes. Also, just because it came from Mouser or Digikey, is not a 100% guarantee against fakes. Its EXTREMELY unlikely, but still possible. The sheer volume these companies process in a DAY would make our heads spin. It is inevitable some fakes make it through. And if it does happen, in my opinion, it will be some of these less common parts, such as these srams.

BloodyCactus, if you are unwilling to provide the photo, you don't have to. I didn't think my request required such pre-aproval or justification.

I am well aware that Mouser, Newark, and Digikey are some of the largest IC suppliers. I order from them frequently, including futureelectronics (often cheaper, but with less selection).

There was a report on the news 2 years ago which identified 10% of our pharmaceuticals bought at legitimate pharmacies are counterfeit. Same for many other products sold in stores. I can imagine that up to some percent may make it into the IC business as well.

We also do not know 100% that the SRAM sourced from aliexpress, ebay, and from other small vendors are fake, though I suspect they are rebrands from some discount IC manufacturer. If Mouser is also selling the same IC's then this may provide some reassurance or it may just look like Mouser got the fake stuff. However, if the SRAM looks genunie, then I might buy some. Recently, a fellow forum member bought what was photographed to be authentic 12 ns SRAM. Then they arrived, the actual product differed from the photo - the actual product contained the same stereotypical look of the alleged counterfeit product.

When I got in contact with a few IC manufacturers about their 10 and 12 ns SRAM in DIP, they informed me that they are not produced anymore.

feipoa wrote:

BloodyCactus, if you are unwilling to provide the photo, you don't have to. I didn't think my request required such pre-aproval or justification.

I'm still digging around, I have.. quite the un-ordered collection of thousands of parts here, ordered by project rather than just by IC... 😀 stocktake never completes 🤣!

feipoa wrote:

When I got in contact with a few IC manufacturers about their 10 and 12 ns SRAM in DIP, they informed me that they are not produced anymore.

https://www.idt.com/products/memory-logic/sra … nous-static-ram

well, IDT list it as active, and their buy page take you to mouser. SOJ + TSOP no longer made in 12ns but dip is still active.

on the subject of fake SRAM; do they test out properly when installed in the motherboard? would fake SRAM be able to report to the motherboard as being what you expect it to be? or is it a case where, if they are fake/counterfeit, you would know straight away once you try to get your board to pick them up?

Well, I recently bought 10x 128kx8 chips for my 486. they claimed 10ns (similar to this listing: https://www.ebay.com/itm/10pcs-IS61C1024-10N- … =item3d686829d9 )

They LOOKED okay. But I have yet to test them. The board I bought them for will only take 256k chips. 😜

I fully expect mine to be some other chip brand, maybe 15ns marked as 10 if it even started life as an ISSI.

I think I had contacted Winbond and ISSI, but not IDT. I was trying to determine if they ever produced, or were still producing, 10 ns 32kx8 and 128kx8 in the DIP package.

pico1180, counterfeit SRAM has worked perfectly fine for me, however I usually get 1 in 10 that are bad from the onset.

The IDT parts look promising - would be cool if they save the day as all other vendors' DIP packaged products are, no surprise, out of stock and the "goods" traded on various sites counterfeit. I only have 5 genuine 12ns UMC srams and each piece cost a "lot".
I do highly doubt that an authentic 10ns DIP IC can be bought anywhere at least if you're a JoeBlow 20-100 piece buyer. As far as I remember few manufacturers had less than 12ns ICs in DIP format.
I'll definitely buy a few pieces from mouser... would be too good to be true though.

@Debs: you could get by with high quality 15ns parts if you're lucky. I have one board(LA486E Rev.c2) running at 50mhz(2-1-2) with a single bank/tag filled with 15ns UM61M256K-15/9534S chips. BUT you have to select and be patient.

UMC/Winbond chips are good for overclock, that's for sure.

luckybob wrote:

Well, I recently bought 10x 128kx8 chips for my 486. they claimed 10ns (similar to this listing: https://www.ebay.com/itm/10pcs-IS61C1024-10N- … =item3d686829d9 )

They LOOKED okay. But I have yet to test them. The board I bought them for will only take 256k chips. 😜

I fully expect mine to be some other chip brand, maybe 15ns marked as 10 if it even started life as an ISSI.

I have just made an offer on a couple of lots from that seller. Will team them up with 12 ns tag from Mouser. The 10 ns 1024K are a great price, even if my offer is not accepted. Not too bothered if the tag restricts me to 12 ns, as no 486 runs the bus that fast, so overclocking should be easy 😀

Interesting to see the 2015 date code on the SRAM chips in the above eBay link. My 128kx8 have 2004 datecodes. Super Fast 486 Cache - 10 ns Looks like some discount IC manufacturer discovered that there is still market for these chips.

Edit: $10 for 10 pieces with free shipping is the best value I've seen thus far.

BloodyCactus wrote:

I'm still digging around, I have.. quite the un-ordered collection of thousands of parts here, ordered by project rather than ju […]
Show full quote

feipoa wrote:

BloodyCactus, if you are unwilling to provide the photo, you don't have to. I didn't think my request required such pre-aproval or justification.

I'm still digging around, I have.. quite the un-ordered collection of thousands of parts here, ordered by project rather than just by IC... 😀 stocktake never completes 🤣!

feipoa wrote:

When I got in contact with a few IC manufacturers about their 10 and 12 ns SRAM in DIP, they informed me that they are not produced anymore.

https://www.idt.com/products/memory-logic/sra … nous-static-ram

well, IDT list it as active, and their buy page take you to mouser. SOJ + TSOP no longer made in 12ns but dip is still active.

The IDT parts are fakes too - maybe a long time ago there were authentic ones to buy.
Anybody who can buy authentic 12ns srams in SDIP format in 2018... raise your hand. Even some of the ones in SOJ format are chinese fakes.