ive got an amd k6-2 400 that pushed out a WU every 24hrs with 64mb
i had 384mb in it an was dribbleing out a WU every 36-48 hrs
took the 384 and put it in a system runnin a celery 300a @ 450 and its
kickin em out every 12hrs
so the on board cache things seems to make sence to me
plus ive heard that before with problems people have with amd k6 while
playin Quake
seems a slower pentium/celery with the same mem will have more fps than the
amd
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, September 26, 2001 10:00 AM
Subject: Re: RAM, etc.
>
>
> I think I can explain why K6s and K6-2s could get slower after adding RAM:
> it's because the L2 cache they use is direct-mapped. I won't go into a
full
> discussion of the various caching methods, but I'll need to explain some
> basics. Note that I'm not an expert on this caching stuff so I may be in
> error on some things, but generally this explanation should be right.
> Direct mapping is simple to understand, but not easy to explain.
> Essentially, a given cache line can only cache data from a certain block
of
> main memory. So, for example, let's say you have a K6-2 with 128MB of main
> RAM and 512K of 64-bit-per-line (I'm not sure if that's how it's done for
> not, as that's one of the things I'm rusty on, but I'll use this possibly
> unrealistic example as a basis for explanation) L2 cache. That means that
> each line of cache stores 8 bytes (8 bits per byte, 64/8=8). 512K is equal
> to 524,288 bytes, or 65,536 cache lines in this example. Thus, the main
> memory would be effectively broken up into 65,536 segments, and each of
> those segments has one specific cache line it can use. Now, 128MB is
> 134,217,728 bytes. That divided by 65,536 gives 2048, or 2 kilobytes,
> meaning that, in this case, each 2-kilobyte chunk of main memory has 8
> bytes of cache associated with it. If the main memory size were increased
> to 256MB, each 16K of main memory would have 8 bytes of cache. So, as you
> can see, direct-cache mapping is not very effective with large amounts of
> RAM, because it's a very inelegant method of caching; if you have a
> gigabyte of main memory, and only use the first 128MB, 7/8ths of your
cache
> will be wasted caching nothing because its associated memory blocks are
> unused.
> Now, there's a more intelligent method of caching called associative
> caching. Fully associative caching, which is rather rare, means that any
> data anywhere in main memory can be stored anywhere in the cache. There's
> also set associative caching, which I'm more unclear on. The Pentium !!!
> "Coppermine" processor uses 8-way set associative caching with its L2
> cache. At this point, I'm going to cheat and copy a URL to explain things:
>
http://www.instantweb.com/D/dictionary/foldoc.cgi?query=set+associative+cach
e
> Basically, fully-associative cache is difficult to implement, and as that
> entry explains, 2-, 4-, 8-, and 16-way set associativity (in order of
> increasing performance but also increasing complexity of implementation)
> allow for almost the same performance as full associativity, but are not
> that much harder to implement than a direct mapping method.
> Anyway, this should all help explain why processors with on-cartridge or
> on-chip caches are not likely to suffer performance reductions when main
> memory is added, whereas processors with direct-mapped cache on the
> motherboard are.
>
> Evan
>
> Broc Olson writes:
>
> >
> > Agreed. My landlord is on a p3 450. When she had 32 megs she was
hitting
> > about 30 hrs a WU. She added another 64 megs and is now doing a WU in
about
> > 15 hrs. Given what I've seen....p2's and p 3's benefit from the
additions of
> > ram while the AMD K6/2's loose. I don't know about the Celerons or the
p4's
> >
> > Broc Olson < Byark!>
> >
> > ----- Original Message -----
> > From: Jeff Gerst <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Tuesday, September 25, 2001 10:13 PM
> > Subject: Re: RAM, etc.
> >
> >
> > >
> > > well that may be about right, it was frustrating discovering the time
went
> > down
> > > as i removed ram from the computer, i started with 128, added another
128
> > times
> > > went up so i subtracted down to 64 and it was even better than when it
had
> > 128,
> > > i do not remember the relative times now, but what i noticed was a
K6/2
> > 400 was
> > > maybe 18 hours on the old version and a PII 400 was 10-11 hours, both
> > running
> > > same bus speed and more ram in the PII etc. that was frustrating since
> > then i
> > > donated the PII to my mom and built others to take its place...
> >
> >
> >
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