if the cache chips are soldered on the board, 9 times out of 10 that's a BAD sign. If you look, the bios is probably hard soldered as well. I would check first to see if you have a FAKE cache motherboard. A picture the board and a close-up of the cache and we can tell you whats going on.

I currently have a similar motherboard. With hard-soldered cache. And Lucky for me, it has actual real cache. But in addition to the cache being permanent, the jumpers that would normally let you upgrade are also missing.

[Thread moved to Marvin Section]

15ns is slow?

Here is a picture of the cache:

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Here is a picture of the BIOS chip (socketed) and the Dallas RTC:

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I guess 15ns isn't very slow, but I wanted 12ns, and for my purposes, even that feels slow.

Dude 486 wont benefit from 12ns, even 15ns is overkill, these days there were mainstream 20ns and 25ns chips.

Dude 486 wont benefit from 12ns, even 15ns is overkill, these days there were mainstream 20ns and 25ns chips.

First of all, thank you and everyone else for replying. Second, I was basing my observations on the slight difference between 20ns and 15ns in 5x86 benchmarks.
But if I understand what you mean, the 486/5x86 would bottleneck the 12ns too much to take any advantage at all?

I was hoping to go up to 512K to be able to cache as much as 128MB EDO RAM by the way. Not sure if that really changes much based on what Cyberdyne said.

Now my dream of a benchmark 486 is fading quickly from my vision. (Disclaimer: the drama depicted in this writing does not necessarily reflect the views of the OP, as he is extremely bullheaded, and does not like to listen to reason.)

It will be of benefit if you run the bus faster than 40MHz....

I've decided that I'm not going to change the cache chips on the Shuttle HOT-433 motherboard until I get some benchmarks out of it with the normal cache first and reacquaint myself with soldering/desoldering (also because of the negativity toward changing the chips that I received while discussing it with experienced folks).

Meanwhile, I'm going to be reviewing the hardware that I have available to use during the benchmark and "final" build.

To be quite frank, its not possible. You have a single bank of 512kb chips. Which gives you 256kb. The only upgrade are 1mb chips. thus giving you 512k. HOWEVER, past 256k you will need to upgrade the tag ram. But if you look, your tag ram is the small 256kb chip. That chip cannot be upgraded as the next size up is too big for the hole!

This has been my major hurdle to making a 486 system. I want 1mb cache and I wont accept anything less. I also want edo ram and 256mb of it. That limits me to the very late gen 486 boards and they seem to be as rare as virgins in a planned parenthood.

luckybob wrote:

To be quite frank, its not possible. You have a single bank of 512kb chips. Which gives you 256kb. The only upgrade are 1mb chips. thus giving you 512k. HOWEVER, past 256k you will need to upgrade the tag ram. But if you look, your tag ram is the small 256kb chip. That chip cannot be upgraded as the next size up is too big for the hole!

This has been my major hurdle to making a 486 system. I want 1mb cache and I wont accept anything less. I also want edo ram and 256mb of it. That limits me to the very late gen 486 boards and they seem to be as rare as virgins in a planned parenthood.

That last part made my day.

As for the first part; I too dream of a 1MB cache 486 running 256MB EDO, but for now I'm trying to work with what I have so I don't go spending money that I don't have on stuff I can't afford. But I did have a chance to buy cache chip that supported 32k x 8 for the TAG as well as 32 pin 128k x 8 12ns cache chips for 512KB but I waited too long for that as well... Now I'm kinda stuck waiting to see if it'll be listed on Ebay (at a very cheap price).

EDIT: I had no intentions of putting more than 128MB in this board as that's the max that it'll handle properly anyway with every possible upgrade.

luckybob wrote:

To be quite frank, its not possible. You have a single bank of 512kb chips. Which gives you 256kb. The only upgrade are 1mb chips. thus giving you 512k. HOWEVER, past 256k you will need to upgrade the tag ram. But if you look, your tag ram is the small 256kb chip. That chip cannot be upgraded as the next size up is too big for the hole!

The Shuttle HOT-433 motherboard states that a TAG of 32K x 8 (256 Kbit) is sufficient to instruct a single bank (4 chips) of 128 K x 8 (512 Kbytes of L2 cache). It also mentions that a larger TAG RAM isn't needed until one goes up to 1024 Kbytes of double-banked L2 cache, in which case a 64 K x 8 (512 Kbit) TAG would be required.

Anonymous Coward wrote:

It will be of benefit if you run the bus faster than 40MHz....

I am curious how this is determined. I figure 15 ns is 66.67 MHz if you take the inverse. I wonder if it is only sufficient for the cache to be just barely faster than the FSB, or is there some sort of Nyquist criterion here where the cache need be 2.5 times faster than the FSB? And if not, are cache wait states required? I figure that since 15 ns SRAM was used in Socket 5 boards for 66 MHz FSB systems, it must be sufficient for any 486. Oddly enough, the slowest L2 cache setting of 3-2-2 is required for operation at 66 MHz using w/15 ns cache and a 12 ns TAG.

nemesis wrote:

...as 32 pin 128k x 8 12ns cache chips

Where did you find a 128K x 8 chip (marked as 1024K) in DIP format which runs at 12 ns? I've only had success finding 32K x 8 chips at 12 ns, which were often found in socket 7 motherboards. If you are going to have 1024 Kbytes of L2 cache, it seems that only a 64K x 8 TAG is required (externally marked as 512K).

First of all, thank you everyone for your very informative posts. You have solved a lot of issues for me with your technical but easy to read explanations.
And your questions enable me to redirect my usually confused gaze to the correct area to solve the problem or at least embetter my knowledge of the subject at hand.

Second, I think I was doing my math wrong for calculating the speed of cache memory if it's 66.67 (no surprise as I'm horrible with math now that I'm several years away from constant practice). Which makes it easier for me to settle with 256KB or 512KB at 15ns.

Where did you find a 128K x 8 chip (marked as 1024K) in DIP format which runs at 12 ns? I've only had success finding 32K x 8 chips at 12 ns, which were often found in socket 7 motherboards. If you are going to have 1024 Kbytes of L2 cache, it seems that only a 64K x 8 TAG is required (externally marked as 512K).

A gentleman that works with semiconductors, ICs and such items was asking for about 60 USD for it, I decided not to go for it because of the price and I thought it would be easeir to acquire at a lower price.
In retrospect, I didn't check the width of the chip to see if it would match the hole size... that could be a problem too.