Can anyone explain what is TAG RAM?

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Can anyone explain what is TAG RAM?

Postby Cga.8086 » 2017-11-08 @ 05:13

fake cache motherboard
tag ram is the one below the upper yellow triangle, the markings on the tag ram are equal as the cache memory ram
Image


same board with real cache
tag ram markings is equal to the real cache:
Image



so what is tag ram? is is just another cache chip ? or tag ram is different from the rest? is tag ram sold on ebay ? i have only seen cache being sold.

so....
cache is fake + tag ram is fake
i know where to buy cache ram,
but where can i buy tag ram???????
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Re: Can anyone explain what is TAG RAM?

Postby luckybob » 2017-11-08 @ 06:09

it is the same chip.

read all about it here: http://www.pcguide.com/ref/mbsys/cache/ ... ity-c.html
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Re: Can anyone explain what is TAG RAM?

Postby Cga.8086 » 2017-11-08 @ 11:27

so i can swap the tag ram with one ofvthe cache modules. it is the same.nothing special or different
Last edited by Cga.8086 on 2017-11-08 @ 14:20, edited 1 time in total.
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Re: Can anyone explain what is TAG RAM?

Postby jesolo » 2017-11-08 @ 11:40

Depending on the total size of the cache installed, the TAG RAM size could be different to the rest of the cache RAM.
Best would be to refer to the manual (or whatever source you can obtain the jumper settings from) to confirm.
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Re: Can anyone explain what is TAG RAM?

Postby BeginnerGuy » 2017-11-08 @ 12:00

In other words they are the same exact kind of SRAM chips you use in the other slots, but sometimes a different size is required and you want to check the boards manual.

For example, on this random board I picked. Scroll down to the section on cache and you'll see bank 0, 1, and tag.
http://stason.org/TULARC/pc/motherboard ... R-1-4.html

For 256K you would just need to buy 9x 32kx8 SRAM chips, but for 128k you would use (4) 32k x 8 with (1)8k x 8 SRAM chip used for TAG.

As for the purpose of TAG ram, in a nutshell, instead of storing data (banks 0 and 1 are your DATA STORE), it holds identifiers (pointers) to say what data is in those data stores and what location from RAM it came from. When a program points the CPU to a memory location in RAM, the TAG chip should say whether or not (Hit or Miss) that data has been cached for faster access. This is called a Cache Lookup
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Re: Can anyone explain what is TAG RAM?

Postby amadeus777999 » 2017-11-11 @ 21:16

Up until 512K you can get away with a 16Kx8 sram as a tag chip BUT there could be boards that do not accept a chip less than 32K in size(or other than 8K at a speific cache size) as a tag.
As stated before, peek into the manual but don't take it as gospel.

Why would you take the gamble then? Because authentic smaller sized chips may still be easier to get at higher speeds(W24129AK-12 being an example on ebay).
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Re: Can anyone explain what is TAG RAM?

Postby candle_86 » 2017-11-14 @ 00:01

How can you tell if you have an 11bit tag, trying to figure out on my hx board
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