I always fill all 9 sockets with 32K chips for 256KB Cache. The ones I have are 15ns and can be purchased new from Element14:

http://au.element14.com/jsp/search/productdet … i-55c5-00001621

You will need 9 of them. I use these chips in all my motherboards 😀

Most motherboards have 1 Tag chip + one or two banks of 4 chips each. Some motherboards (my Forex chipset 486) needs 2 Tag chips for 256KB.

I have read that filling all sockets is sometimes faster if the board supports interleaving, but look I don't think it makes a difference.

The MAIN thing is having ANY cache 😀

Some boards that 512KB but then you need different chips. Main benefit: Larger cacheable size.

And checking the cachable size. But on a 486 there is only so much RAM one needs unless you are another one who wants to build the "Ultimate 486" 😁

Mau1wurf1977 wrote:

I always fill all 9 sockets with 32K chips for 256KB Cache. The ones I have are 15ns and can be purchased new from Element14:

http://au.element14.com/jsp/search/productdet … i-55c5-00001621

Thanks. Ordered (from their U.S. store)!

256K vs. 128K would probably be felt. Nice. I wonder how much cache I had on the same board I ordered new, from ASUS, back in the '90s? Did they come std with 128K?

bp

blakespot wrote:

256K vs. 128K would probably be felt. Nice. I wonder how much cache I had on the same board I ordered new, from ASUS, back in the '90s? Did they come std with 128K?

I think 256K was already standard for quite some time by the time the PVI-486SP3 came out. I suspect the later revisions of these boards were sold off as a cheap alternative to Pentium systems, so they included only half the cache to keep the price down.

Performance-wise, 128K vs 256K probably does not make much of a difference, but it affects the size of cacheable RAM.

So, I will have 256K L2 cache in this board when the chips arrive. All 15ns. 9 chips. I hope that is fine - tag not faster than rest...

That means 32MB cached in WB mode. The board has two SIMM slots, and it has a single 64MB stick in it. I want 32MB max, for cached. Should I find two 16MB or is one 32MB ok - pairs better? What is the type, speed of RAM I want for this board?

Thanks.

bp

RAM have ratings like 80, 70 or 60ns. It's not hard to find 60ns 72 pin SIMM memory. 30 pin though, much harder.

There is also EDO memory, but the motherboard must support it.

Some motherboards support memory interleaving, which is better performance if all the slots are filled. I simply like to fit all the slots and have 4 x 4MB EDO 60ns in my 486.

blakespot wrote:

That means 32MB cached in WB mode. The board has two SIMM slots, and it has a single 64MB stick in it. I want 32MB max, for cached.

Under DOS, the cacheable area is a non-issue, since memory fills from "bottom up", and hardly any DOS program uses more than 32 MB.
Performance is the same with one or two modules, the board does not support EDO memory. 60ns should be sufficient for fastest RAM settings.

I've got 2x 32MB in my PVI-486SP3, simply because I like to use half of it as RAM disk.

Let's not confuse DRAM interleaving and cache interleaving.

Every 486 motherboard I have ever seen supported cache bank interleave. (Though I'm sure there are a few that don't)

DRAM interleave seems pretty uncommon. Not too many of the mainstream 486 chipsets support it, particularly the PCI generation. PCI boards seem to get pretty decent memory scores without it though. I know that the SiS 411/406 and Symphony 461 chipsets can do it. Probably a C&T or VLSI can do it. I think the Intel Saturn chipset could do it, but don't quote me on that one. I've never been able to find a proper list.

Mau1wurf1977 wrote:

I always fill all 9 sockets with 32K chips for 256KB Cache. The ones I have are 15ns and can be purchased new from Element14: […]
Show full quote

I always fill all 9 sockets with 32K chips for 256KB Cache. The ones I have are 15ns and can be purchased new from Element14:

http://au.element14.com/jsp/search/productdet … i-55c5-00001621

You will need 9 of them. I use these chips in all my motherboards 😀

Most motherboards have 1 Tag chip + one or two banks of 4 chips each. Some motherboards (my Forex chipset 486) needs 2 Tag chips for 256KB.

I have read that filling all sockets is sometimes faster if the board supports interleaving, but look I don't think it makes a difference.

The MAIN thing is having ANY cache 😀

Some boards that 512KB but then you need different chips. Main benefit: Larger cacheable size.

And checking the cachable size. But on a 486 there is only so much RAM one needs unless you are another one who wants to build the "Ultimate 486" 😁

So more cache is always better? Or is it just how much ram you are using on the motherboard?

Robin4 wrote:

So more cache is always better? Or is it just how much ram you are using on the motherboard?

I haven't done any investigations into 128 vs 256 vs 512KB Cache so I can't answer this question. Personally I always go with 9 chips and 256KB Cache. I haven't had any issues and you get away with buying the same 9 chips rather than having a different TAG and things like that.

Here's my thread about upgrading my PVI-486SP3 to 512kb cache:

Re: Asus PVI-486SP3 with 512kb cache

Didn't really 'feel' much faster, but 512kb certainly works.

http://www.bytecellar.com/2013/12/28/dos-box-build-update-1/

Blog Post: DOS Box Build: Update #1

Wow that Cache arrived fast!

Why are some of the sockets longer?

hwh wrote:

Why are some of the sockets longer?

They are for 512k and 1024k cache chips, which have 4 more pins. You can either use 4 512k or 8 256k chips for 256Kb cache. Perhaps even 512Kb cache with 4 1024k modules, in case the board supports it.

Mau1wurf1977 wrote:

I always fill all 9 sockets with 32K chips for 256KB Cache. The ones I have are 15ns and can be purchased new from Element14: […]
Show full quote

I always fill all 9 sockets with 32K chips for 256KB Cache. The ones I have are 15ns and can be purchased new from Element14:

http://au.element14.com/jsp/search/productdet … i-55c5-00001621

You will need 9 of them. I use these chips in all my motherboards 😀

Most motherboards have 1 Tag chip + one or two banks of 4 chips each. Some motherboards (my Forex chipset 486) needs 2 Tag chips for 256KB. ...

So,

I just removed the 128K cache and installed the 9 cache chips you recommended, that I ordered. Set jumpers accordingly, powered up. I get no POST and one 4 beeps from speaker in this pattern:

BEEEEEEEEP -- BEEP -- BEEP -- -- BEEP

The 128K cache that was in the board consisted of 4 like chips and a 5th TAG chip that was different spec than the others. I followed what you suggested and used the same chip type for all 9 sockets - TAG is same as cache RAM.

Is that my problem? Does that only work on some boards? Thanks.

bp

EDIT: They look fine.

Here is someone elses board: http://img853.imageshack.us/img853/5590/a5z.jpg

For 128KB Cache, the TAG is different. Same goes for 256KB Cache with 5 chips. But for 9 chips the TAG is the same as the others.

Double check that no leg is bent or not inserted. Can easily happen. Double check all the jumpers. Not much else you can do...

Bah.

I was reseating the cache when I noticed the ISA end of the VLB video card was out of the socket... All fine now. 256K L2. 😀

https://twitter.com/blakespot/status/42244048 … 2645504/photo/1

Thanks!

bp

Hehe I think we all had moments like that 🤣

I wonder how this would perform with some new 10ns SOJ chips on SOJ-to-DIP adapters.