🚀 go-pugleaf

On Mon, 22 Apr 1996 00:17:15 GMT, paul@pstancer.demon.co.uk (Paul Stancer)
wrote:

> I've been following this thread with interest for some time, as I'm 
> thinking of upgrading my VESA board to a Pentium PCI board.
> 
> Could someone point me in the direction of a good FAQ on the folowing 
> jargon (COAST, async cache, pipeline cache, etc, etc). I'm especially 
> interested in the cache situation, as I has a friend who bought a 
> Pentium from Time computers which arrived without any form of cache. 
> When he contacted Timethey stated that Pentiums didn't come with a cache!
> 

I think COAST is just a cache's physical package (Cache On A STick). As far
as speeds go:

Pipeline burst > Async cache ("normal cache" like you'd have on your 486) >
no cache.

I've seen figures of PB cache ~ 15% quicker than no cache and async cache ~
7% quicker than no cache. Obviously this depends on hit rates and usage,
but seems to be a reasonable guide (ie it may well be better to go for a
120MHz+PB cache than 133MHz w/o cache - just EDO Ram)

> He got his money back eventually.
> 
> Also, what the ****** is EDO Ram.

Just to confuse things further there's at least 3 types of Ram around:
70ns DRams (which you might already have), 60ns DRams, and EDO Ram (I think
this is rated as 60ns, someone correct me if I'm wrong?).

EDO Ram is quicker on subsequent accesses, so it ca be used as a poor
person's cache. This gives speed increases of 5 to 10% over similar rated
DRams, and is similar to a reasonable amount (eg 256K) of async cache.

So the quickest is EDORam+PB Cache, then things get a bit  hazy. So Time
try to avoid using PB cache by saying EDORam is same as async cache + DRam,
since EDORam adds about 10% to ram costs (ie it's a lot cheaper for 8meg
machines, like they mostly sell - but why buy a Pentium with 8 megs?)

By the way, even EDORam + PB Cache doesn't future proof you, as new ram
technologies are on the way in the next 12 months (so we might see them
next year in midprice PCs).

--- 
Hemal Popat
hemal@popath.demon.co.uk