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Socket 5 MOBO Assistance..

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Smack2k

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Hey, this is my Pentium 1 (75 MHZ) SX969 MOBO (I think)

MOBO.jpg

The reason I say I think is that it says its for a 60/66 MHZ Proc, which mine is not...but after looking through statson.org's Socket 5 MOBO's, this is the only one that came up..

Here is the RAM config:

MOBO RAM.JPG

Questions:

It says I can upgrade to 256 MB RAM...but have been reading and talking with others here and they all point to 64 MB being the limit for P1...so which is it? If I go higher than 64, will it make a difference?

Also, my cache memory isnt full, is filling up the empty slots (about 6) going to make any noticeable differences in terms of performace?

Thanks!
 
There is no 64 MB limit for P1. You can add as much RAM as the mainboard supports. My socket 5 ( http://stason.org/TULARC/pc/motherb...ORATION-Pentium-PH5-REV-1-1.html#.USqmHDBkOP8 ) can address up to 128MB and I have been working fine with it. Of course assuming you are not under MS-DOS 6.22 or lower (that could see either 32 or 64 MB as limit). Use MS-DOS 7.1 or higher and it will work.

Now if the extra RAM will make any difference ... well that's a good question. Under DOS, or Windows 3.11 you'll never get to use too much RAM. If you install WIN98 though, you might. But that is not all. There is a problem with caching the extra memory. I've heard people saying that you need 512K L2 cache in order to cache 128MB RAM and probably 1024K for 256. If you don't have that much cache, you get a performance hit and the extra RAM might make the PC slower. Personally, however, I've yet to benchmark these scenarios.

As for the cache upgrade, the more the cache installed, the higher the performance of the system, but the difference is not that big. Assuming of course that you have at least the amount needed to cache the whole amount of the RAM.
 
Makes total sense...thanks for the explanation!

The cache chips installed right now have this:

UM61m 256K-15
9253g r42023

I assume I need the same chips for the empty slots? If so, what exactly am I looking for? I see tons of 256K-15 chips on ebay and other places...

Thanks again!
 
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Some of the Pentium boards (intel chipsets) had a limit on which amount of memory could be cached.
That didn't mean they did not support more RAM, but it could result in slower performance when installing more memory than the limit.
Chipset Cachable limit
430VX 64MB
430HX 512MB
430TX 64MB

Not sure what kind of SIS chipset this is and if it has a limit like that.
 
The P75 isnt Socket 5?

I guess my issue then is even stranger as the cradle the proc sits in says Socket 5 on it...

So my confusion continues...I found something that I can use to help identify MOBO..will try that out tonight and will also post a pic of the socket info and the proc picture as maybe I am seeing something wrong!
 
Here is my MOBO in question:

photo-1.jpg

Here is the Proc - Dirty, I know...needs cleaned...

P 75.jpg

Says - Pentium - A80502n-75 SX969
The Proc Holder says Socket 5

Chip:

photo-3.jpg

BIOS Chip:

photo-4.jpg

Cache Bank:

photo-5.jpg

Chip says - UM61 M 256K-15
9523G R42023


Anyone know what this is?

It says Socket 5 - but its a P 75 MHZ...so I am not sure

Also, need to find out what type of cache it is so I can find what I need to fill the banks (if applicable)

Thanks!
 
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Oh, interesting, is this the board you told me about?

Yea, the cache I just sent to you won't work in that board. These are cache sticks, not DIPs.

But that's ok, you can keep them or sell them if you want.
 
OK...sorry....I wasnt exactly sure what I was looking for...

The other RAM was more important from you anyway...so THANK YOU!!!

Now to find the particulars about this board!
 
It looks to me that you correctly identified the board as the MTech R512, CPU socket types don't match though.....

I'll be back.
 
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I know when it was on last it was running at 75 MHZ...hence my serious confusion..I havent had this particular machine on for a long while as my other P1 is the one I have running....

Also, do you know what type cache sticks this can take (20ns / 25ns etc...)
 
The P75 isnt Socket 5?
Click to expand...

You've got it backwards... the P75 is Socket 5, but the motherboard in the illustration says it's for P60/P66 chips, which are Socket 4.

But your board is certainly very similar to that one otherwise, so either the TH99 data is wrong about what CPUs it supports, or perhaps your board is the younger brother of that one.
 
Old Thrashbarg said:
You've got it backwards... the P75 is Socket 5, but the motherboard in the illustration says it's for P60/P66 chips, which are Socket 4.

But your board is certainly very similar to that one otherwise, so either the TH99 data is wrong about what CPUs it supports, or perhaps your board is the younger brother of that one.
Click to expand...


That makes sense...thereby heightening my confusion!!
 
Smack2k said:
Also, need to find out what type of cache it is so I can find what I need to fill the banks (if applicable)

Thanks!
Click to expand...

The cache memory the board takes is of the following types:

32Kx8 chips (very common and probably easy to find cheap). The maximum cache you get with 8 such chips is 512K
64Kx8 chips (very rare, difficult to find cheap). The maximum cache you get with 8 such chips is 1024K
128Kx8 chips (also rare, difficult to find cheap). The maximum cache you get with 8 such chips is 2048K

And you also need 1 chip for the TAG slot of the cache memory. Eg the R512 board needs 1 64Kx8 for the TAG of 1024K or 2048K, or a 32Kx8 to TAG 512K or 256K

If I'm not mistaken the following ebay seller has 128Kx8 and 64Kx8 cache chips (someone correct me if I'm wrong). But as you can see, they are not very cheap. He sells one 128Kx8 for $5 and one 64Kx8 for $4:

http://www.ebay.ie/itm/110887907277...X:IT&_trksid=p3984.m1438.l2649#ht_3344wt_1163
http://www.ebay.ie/itm/110887926068...X:IT&_trksid=p3984.m1438.l2649#ht_3344wt_1163
 
So any chip of those sizes will work?

I know my 486 machine states you HAVE to use a certain cache chip (20ns)....according to the manual...or it that more of a recommended thing?

Does that apply at all here? Or can I use any cache chip with those sizes you mentioned above..How do I tell what is what by looking at the chip? Seems like everyone I see says 256K-15 or something similar..how do I tell the sizes (32kx8 as opposeed to 128kx8)
 
Smack2k said:
I know my 486 machine states you HAVE to use a certain cache chip (20ns)....according to the manual...or it that more of a recommended thing?
Click to expand...

20ns cache memory was the case in 386 and early 486 boards. Mid to late 486 and early Pentiums all used 15ns. All 386 boards in which I replaced the 20ns with 15ns modules are working fine and I can use tighter timings in the BIOS for better performance with the faster 15ns chips.
 
Usually the number at the end of chips designation relates to the timing. For example, one of the chips linked to above has a 15N which should imply 15ns chips.

Find the markings on the chip, google the specs, make sure the specs match what you need, and hope the retailer posted a good picture of the correct stock.

I would suggest trying your system with its current cache. Find out what bottlenecks it, maybe turn the cache off in the BIOS, get an idea for how your usage of the system would be affected by the changes you make.
 
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