As far as I understand it, tag SRAM chips are just SRAM chips, and can be the same as the cache chips, but that depends on the configuration.
Namely, the tag SRAM is used to track the contents of the cache. So the amount of tag SRAM required depends on your cache configuration.
In some configurations the tag and cache chips can be the same, so all 32kx8 for example. In other case, you may have for example 8kx8 tag SRAM chips and 32kx8 cache SRAM chips.

See the manual of my 486 motherboard for example, which explains the possible configurations (and jumper settings):

Scali wrote:

As far as I understand it, tag SRAM chips are just SRAM chips

If Tag SRAM chips are the same thing as cache chips, then could I take 5 MT5C1008 (SRAM, 128K x8 DIP32) chips and put them in all 5 cache slots.

I wouldn't have to worry about only installing 4 MT5C1008 (SRAM) along with a separate IS61C1024-20M (TAG Chip DIP32).

The red denoting locations U15, U19, U24 and U30 where cache chips go, and green denoting U35 where the tag SRAM chip goes.

Nothing stupid as there can be trial and error involved if the motherboard manual gives dubious specs for the tag ram size for example.

I have come across two boards that state that a 16K sram is sufficient as a tag and Boom... the system hung until a 32K one was supplied(same speed grade). With a 32K you can't go wrong especially in a board with only 4(+1) sockets(max. 512KB when 128s are suported).

It can be of advantage to have the sram chip which serves as the tag ram to be of one speed grade higher(15 when paired with 20s) but as long as you stay in the 25-40mhz fsb region you'll be on the safe side with 15s(at slower timings 20s may cut it too).
A single bank system, like yours, is a bit more demanding when it comes to chip timings though - better use 15s to avoid any hassle.

Should your system get stuck before accessing the hard-disk try to change from write-back to write through mode as latter is less "demanding". No guarantees though.

amadeus777999 wrote:

Nothing stupid as there can be trial and error

Very true. At any rate, I bit the bullet and purchased a lot of 11 of these...

They're 20ns so it fits the profile. PB wanted you to have 15, 20, or 25ns for cache.

I'm also going to get a 10 count of 32kx8 15ns cache. It will only give me 128k of cache, but if the 512k doesn't work out, I have something to fall back on.
At the same time, I have to get a 10 count of Micron Fast Page DRAM.

I hate having to buy in bulk to get what I need. I called around to try and find ISSI IS61C1024-20M chips, but you need to place a minimum order of 200 in order for them to sell to you (500 in some places).
More money than sense in this case... don't tell my wife.

Flakchak wrote:

Very true. At any rate, I bit the bullet and purchased a lot of 11 of these... […]
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amadeus777999 wrote:

Nothing stupid as there can be trial and error

Very true. At any rate, I bit the bullet and purchased a lot of 11 of these...

20ns.jpg

They're 20ns so it fits the profile. PB wanted you to have 15, 20, or 25ns for cache.

I'm also going to get a 10 count of 32kx8 15ns cache. It will only give me 128k of cache, but if the 512k doesn't work out, I have something to fall back on.
At the same time, I have to get a 10 count of Micron Fast Page DRAM.

I hate having to buy in bulk to get what I need. I called around to try and find ISSI IS61C1024-20M chips, but you need to place a minimum order of 200 in order for them to sell to you (500 in some places).
More money than sense in this case... don't tell my wife.

In regards to the srams - be aware of scammers and fakes albeit they may be less common when acquiring lower speed parts. Try to get 15ns to be on the safe side both speed and deal wise.

From which "shop"/site are you buying?

I'm using ebay right now. At this point in the game for me, I'm looking at feedback as well as time on ebay.