Would it technically be possible to use a S370 socket for cache?

MadRat

Lifer
Oct 14, 1999
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This is one of my zaniest ideas yet!

Some people around here like to use SMP. What if they used the second processor to store cache? Imagine you have a dualie board and really don't need the second processor as much as high speed access to your data. What if you could add a 4mb (or better!) of full-speed cache to your system?

Those 4-way and 8-way boards can turn the empty sockets into high speed cache. Not everyone buys an 8-way board and fills them up. Well, this would give them an extra reason to fill one of the empty sockets. Manufacturing costs would be comparable to regular CPUs.

Awwww, the idea of a 1.33gHz cache...
 

Killbat

Diamond Member
Jan 9, 2000
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"Manufacturing costs would be comparable to regular CPUs."

:p

Riiiiight. And if I had to choose between an additional CPU and additional cache...
 

CrackRabbit

Lifer
Mar 30, 2001
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thats an interesting idea...
think you could turn your normal PIII into a PIII Super Xeon Ultra or something.

but on the other hand, the problems associated with doing this are so great, its insane.....

just my thoughts
 

MadRat

Lifer
Oct 14, 1999
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What kind of problems would happen? I'd think it could have its own logic for controlling the I/O requests. Don't processors already swap the contents of their caches?

<<thats an interesting idea...
think you could turn your normal PIII into a PIII Super Xeon Ultra or something.>>

I'm thinking that, too. I've always wanted an affordable L3 cache on a S370 board. Only this idea further simplifies the task of manufacturing since it would fit a current CPU packaging. :D
 

CrackRabbit

Lifer
Mar 30, 2001
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im no motherboard architecture specialist, but i think the problem would be that it would not be in line with the cpu as normal L3 cache would be, it would be basicly on its own seperate bus from the normal cpu, you would have to almost design an entirely new chipset to make it work correctly, the other problem is that i dont belive p3s can adress that much cache memory, but im pretty sure athons can.
 

CrackRabbit

Lifer
Mar 30, 2001
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antother idea is re-instate the COAST modules from the old pentium mobos, just update them so that the cache would run at a much greater speed.
 

Noriaki

Lifer
Jun 3, 2000
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But what are you caching for?

The idea of onboard cache is that it's really fast....
If you put cache on a second CPU socket, the first CPU could only access it at 133Mhz becuase it would have to go across the front side bus to get to it.

L2 cache is built right in so you can go at 1Ghz for the 2mm distance it has to travel. This idea you'd have to go out across the motherboard so you end up really not much faster than main memory....

A bit faster maybe becuase Cache might be lower latency, but still you are stuck to what your FSB can provide speed wise.

I fail to see the benefit...
I suppose it would be like L3 cache to a K6-3 sort of...that's a bit faster than main memory becuase of lower access times, but really...adding 133Mhz cache to a 1Ghz+ CPU isn't really that huge of a benefit.

It certainly wouldn't be anywhere near as good as havin 4MB onboard cache of a Xeon.
 

MadRat

Lifer
Oct 14, 1999
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Doesn't HDT allow much faster access across the bus?

Perhaps it wouldn't work with a S370, but then why not Socket-A?
 

Ciber

Platinum Member
Nov 20, 2000
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noriaki is right. any benefit from this would be killed off by the distance the data would have to travel across the board, waste of time, dont you think someone at intel or something would of done this already if it would actually be worth the trouble?? heheh