feipoa wrote:

The cache in the second eBay link looks similar to mine. Mine work with an 83 MHz FSB. Hi me passes. Memtest passes. CTCM shows all 64 mb is cacheable. But there is no guarantee you’re works - test it.

I'm confused, if it shows 64 mb or the tag ram isn't working or ctcm doesn't detect the tag ram correctly. I tested the chip with the tl866 II plus, it fails every test: data bus, address bus and unit.

My cache looks like this: Super Fast 486 Cache - 10 ns

I just tested it in the TL866 II plus and it passes. Assuming you have your chip inserted in the proper position on the TL866, my guess is that you may have some dead SRAM chips.

This is my chip:
https://imgur.com/a/t7mUyEb

I tried once again to test it on TL866, in both ways just to be sure, same result as before.

I suppose you are right, I got a dead sram chip or just a piece of plastic.

When are the new chips arriving?

Might want to seek a refund on the bogus SRAM.

Nemo1985 wrote:

[...]
You are right, but if they are cheap chinese clones maybe they can't handle the 83mhz bus.. Can I use CACHECHK with more than 64mb to see if it works properly?

Nobody actually makes ancient DIP SRAMs like this anymore, clone or otherwise. What usually happens is that the inscription on existing chips is sanded off and a new one made. Sometimes it is to change the mfg date, sometimes to change the brand, sometimes to label a slow part as something faster and sometimes... no idea, just to stick a different label on it.

Best way to test is just to try it - clock at 50MHz FSB and populate with >64MB RAM. If that fails the chip is just bad. If it works at 50MHz, crank up the FSB step by step and see how far it will go. If it reaches the same speeds as with no TAG (with same CPU and RAM), you're lucky. If not, not.

Note that most Chinese sellers are more than happy to offer a solution in that case, so certainly let them know.

feipoa wrote:

When are the new chips arriving?

Might want to seek a refund on the bogus SRAM.

In a month or so, I just ordered the 10ns and the seller shipped it today. I just ordered 1 piece, should I have ordered more just to be sure?

dionb wrote:

Nobody actually makes ancient DIP SRAMs like this anymore, clone or otherwise. What usually happens is that the inscription on existing chips is sanded off and a new one made. Sometimes it is to change the mfg date, sometimes to change the brand, sometimes to label a slow part as something faster and sometimes... no idea, just to stick a different label on it.

Best way to test is just to try it - clock at 50MHz FSB and populate with >64MB RAM. If that fails the chip is just bad. If it works at 50MHz, crank up the FSB step by step and see how far it will go. If it reaches the same speeds as with no TAG (with same CPU and RAM), you're lucky. If not, not.

Note that most Chinese sellers are more than happy to offer a solution in that case, so certainly let them know.

Thank you for the tip, actually it seems the chip just doesn't work, I mean if it fails the test with xgecu... Unlucky I bought it almost 1 year ago and never bothered to check if it was actually working or not, so no refund, but I will check the newer one as soon it will be here.
I also tried to find such dip28 chips from other sources but as you said they are impossible to find.

If the new orders has similar markings to the SRAM ship I showed in the other thread, I'd have just ordered 11. I had a 10% failure rate. With bad luck, two are dead, and that would leave you 9, which is enough tor 256K + TAG on a system. If you just order 1 piece for testing, you don't know if it was part of the 10%. Minimum, I'd have ordered 3 for testing. And that would let you know if you should have ordered more, or quit.

I still didn't receive the parcel from China, the last day is 4 december, for that time if I still didn't receive it I will order from Aliexpress a stock of 10 sram as you suggested.

In the meanwhile I'm still looking for the 50ns memory, unlucky the only seller is from US and he has crazy shipping price for abroad, is there any US user in there, please?

My longest wait time for a China shipment was almost 3 months. But I think the eBay dispute period is only 60 days. I've found that if 60 days has passed, sellers know it and just don't reply to me. So if it is 59 days and not received, I open a dispute, then refund the money back if it comes within the next 4 weeks. If it passes 3 months, I but the item elsewhere.

Bump thanks to feipoa I have been able to get the 50ns ram (128x2), now I'm undecided about what other components to use, sound card, video card and cpu, any suggestion will be greatly appreciated.
The usage will be mixed, dos and windows 98.
Cpu: K6-2 450 (hopefully 83x5,5) or K6-2 500 (83x6) or pentium mmx 233 (3x83).
Video card: S3 Virge DX 4mb, Matrox Mystique, Trident 3d Imàge 9750.
Sound card: Sound Yamaha YMF719E-S (ISA), CT 4830 Sound Blaster Live! (PCI).

Except for cpu that those 3 are my only choice, the sound and video card I wrote down the first things came to my hand while looking the boxes with old components.

I don't know much about that yamaha model but being ISA should be trickier to run in DOS. Same for video card, I feel s3 will be slower than matrox but it has more dos compatibility.

In the end I've decided for Amd K6 500 (6*83), with a voodoo 3 2000 pci and ESS 1 ESS1969F.

Actually something weird happens, when I use the 128x2 50ns memory the other 32x2mb won't get detected and pc goes nuts, while if I pair the 256 with another 32x2 they get correctly detected, I suspect the 32x2 memory modules don't work fine.

Initially I thought those were the fastest stable settings:
https://imgur.com/a/R3odoNE

Benchmarks:
Speedsys: https://imgur.com/a/F7OCNGB
Doom: 2134 gametics in 680 realtics
Quake 320x200: 70,9
Quake 640x480: 19,7

I was disappointed with the results of memory bandwith and transfer rate, it's clear enough that memory is what make the system crippled despite using 50ns and 83 mhz as bus frequency, I was considering to upgrade the cpu to k6-2+ but it's clearly not worth it.

Then I found that DRAM Turbo Read Leadoff and DRAM Speculative Leadoff when disabled let me use faster timings:
https://imgur.com/a/cxG1AJi

Benchmarks:
Speedsys: https://imgur.com/a/5N932K8
Doom: 2134 gametics in 677 realtics
Quake 320x200: 74,4
Quake 640x480: 20,4

As always any suggestion will be greatly appreciated.

I'm not surprised you have issues when mixing the 128 MB sticks with the 32 MB sticks. Do you only have these issues when the FSB is at 83 MHz? What about 66 MHz? Things get tricky when you push freq. and size limits.

Didn't know about the DRAM Turbo and Speculation leadoff needing to be disabled for faster memory timings. I'll have to look into this on a few of my systems

Well the 32mb 50ns are "high" density, they have just 4 chips, 2 per side, while when I tried the 60ns they have far more, like 8 chips per side.
I tried lower fsb but nothing changes.
Please check if those options let you have tight timings when disabled, I had around 10mb\s difference on memory bandwith, but overall as you can see lower read and write timings give better performance.