P5A Cacheable Area - conflicting information: 128MB or 256MB ?
Sven Koerber
the German mag c't reported that the P5A (with 512KB L2 Cache) has a maximum
cacheable area of 128MB - as a limitation of the chipset. On the lost circuits pages
http://www.lostcircuits.com/motherboard/asusp5a/ I found the following statement:
"... because ASUS went one step beyond and modified the ALiAladdin V chipset, in that
the flawed tag RAM of the L2 cache (in Rev. E of the chipset) was disabled and
replaced by their own 10 bit version. This results in a cacheable amount of 256 MB of
RAM with the 512 kB L2 cache version and 512 MB cacheable with the (yet to be
released) 1024kB L2 version of the P5A."
Can anybody confirm this? If you have 256MB of RAM on your P5A/K6-II-based machine,
would you be so kind to measure performance with 128MB and 256MB and post the results
(and board revision) to the group? Perhaps that would clear things up. My planned
upgrade path was to switch to the K6-III once it becomes really cheap and upgrade my
RAM _then_ - making use of the on-die L2-cache, which is reported to cover all the
RAM you can currently plug into the board. But if it is possible _now_ without a
performance penalty, I'd get more RAM now.
Greetings,
Sven
amdtweakster
equaling 256MB. I was wondering if it did cache more than 128 because of the increase in
performance after added the second stick of RAM. My last mobo was a P5A-B rev. C and I
remember when I tried to run 256 of RAM, it slowed the system down. Here's my latest
Wintune benchmarks. I'm running a K6-III 450 o/c'd to 273, my video card is a Voodoo3
3000 ;~) Thanks for the info!
Sven Koerber
> Hmmm... That explains why my P5A (rev. E) didn't slow down when I added another 128
> equaling 256MB. I was wondering if it did cache more than 128 because of the
> increase in
> performance after added the second stick of RAM. My last mobo was a P5A-B rev. C
> and I
> remember when I tried to run 256 of RAM, it slowed the system down. Here's my
> latest
> Wintune benchmarks. I'm running a K6-III 450 o/c'd to 273, my video card is a
> Voodoo3
> 3000 ;~) Thanks for the info!
Just to check if I understand you right: Using your P5A rev. E and an *AMD K6-II* you
did not notice a decrease in performance? If you referred to the K6-III on the P5A,
its on-die cache should render the chipset Tag-RAM-issue obsolete with any amount of
RAM.
Sven
BTW, your system is roughly 30% faster than my AMD K6-II-350CXT @ 4x100
Tampakis Nikolaos
>
> Hi,
>
> the German mag c't reported that the P5A (with 512KB L2 Cache) has a maximum
> cacheable area of 128MB - as a limitation of the chipset. On the lost circuits pages
> http://www.lostcircuits.com/motherboard/asusp5a/ I found the following statement:
>
> "... because ASUS went one step beyond and modified the ALiAladdin V chipset, in that
> the flawed tag RAM of the L2 cache (in Rev. E of the chipset) was disabled and
> replaced by their own 10 bit version. This results in a cacheable amount of 256 MB of
> RAM with the 512 kB L2 cache version and 512 MB cacheable with the (yet to be
> released) 1024kB L2 version of the P5A."
>
> Can anybody confirm this? If you have 256MB of RAM on your P5A/K6-II-based machine,
> would you be so kind to measure performance with 128MB and 256MB and post the results
> (and board revision) to the group? Perhaps that would clear things up. My planned
> upgrade path was to switch to the K6-III once it becomes really cheap and upgrade my
> RAM _then_ - making use of the on-die L2-cache, which is reported to cover all the
> RAM you can currently plug into the board. But if it is possible _now_ without a
> performance penalty, I'd get more RAM now.
>
> Greetings,
>
> Sven
I'd get more RAM anytime. I have a TX97-XE = guaranteed 64 mb caching
limitation. I have installed 256 mb of RAM on it, and I don't feel any
slowdown. Ok so I feel it sometimes, but very rarely and only with
specific tasks (ie kernel compiling under Linux). Why don't you disable
the onboard L2 cache and see for yourself ? If you're disappointed,
don't buy RAM. If you aren't, go for it.
Now as to your question, trust c't and forget about lostcircuits.
They've lost their circuits. Asus never modified the ALI chipset, the
chipset itself provisions for external TAG RAM usage instead of the
internal one. If you ask me I'd say that, provided it's possible, Asus
would keep using the same design with the external TAG RAM even if they
got their hands on rev. F ALI chipset shipments (which have a supposedly
working internal TAG RAM). That of course would yield the same old 128
mb cacheable range, but does it really matter ? Disable your L2 cache
and find out.
On a side note, Asus has confirmed the same 128 mb of cacheable range
both in tech support replies and in a FAQ somewhere (I think). Also,
Asus has made a statement that they aren't using 1024 kb of L2 cache on
the P5A because they can't find sufficient (or maybe cost efficient...)
supplies of single 1024 kb cache chips (the motherboard's layout
provisions for a single cache chip). Maybe with 1024 kb the caching
limit would indeed be 256 mb, but that's just speculation.
Regards
Nikos Tabakis
Rudolf Palme
Sven Koerber wrote in message <37679EF9...@rhw.uni-muenster.de>...
>Hi,
>
>the German mag c't reported that the P5A (with 512KB L2 Cache) has a
maximum
>cacheable area of 128MB - as a limitation of the chipset. On the lost
circuits pages
>http://www.lostcircuits.com/motherboard/asusp5a/ I found the following
statement:
>
>"... because ASUS went one step beyond and modified the ALiAladdin V
chipset, in that
>the flawed tag RAM of the L2 cache (in Rev. E of the chipset) was disabled
and
>replaced by their own 10 bit version. This results in a cacheable amount of
256 MB of
>RAM with the 512 kB L2 cache version and 512 MB cacheable with the (yet to
be
>released) 1024kB L2 version of the P5A."
>
you can have a look here (in german - should be no problem (for you!?))
http://www.asuscom.de/de/support/techmain/FAQ/mobo_cpu/faq045_cacheable_area
.htm
r.
Rudolf Palme
here we go
http://www.asuscom.de/de/support/techmain/FAQ/mobo_cpu/faq045_cacheable_area
.htm
r.
LBJGH
Larry
Sven Koerber <kor...@uni-muenster.de> wrote in message
news:37679EF9...@rhw.uni-muenster.de...
> Hi,
>
> the German mag c't reported that the P5A (with 512KB L2 Cache) has a
maximum
> cacheable area of 128MB - as a limitation of the chipset. On the lost
circuits pages
> http://www.lostcircuits.com/motherboard/asusp5a/ I found the following
statement:
>
> "... because ASUS went one step beyond and modified the ALiAladdin V
chipset, in that
> the flawed tag RAM of the L2 cache (in Rev. E of the chipset) was disabled
and
> replaced by their own 10 bit version. This results in a cacheable amount
of 256 MB of
> RAM with the 512 kB L2 cache version and 512 MB cacheable with the (yet to
be
> released) 1024kB L2 version of the P5A."
>
amdtweakster
ALi
M1541 A1
100 MHz
9911 T505
XD286710000E
TAIWAN
LBJGH
amdtweakster <garr...@postoffice.pacbell.net> wrote in message news:3769A9DC...@postoffice.pacbell.net...
tzie...@my-deja.com
"Sven Koerber" <kor...@uni-muenster.de> wrote:
> Hi,
>
> the German mag c't reported that the P5A (with 512KB L2 Cache) has a maximum
> cacheable area of 128MB - as a limitation of the chipset. On the lost circuits pages
> http://www.lostcircuits.com/motherboard/asusp5a/ I found the following statement:
>
> "... because ASUS went one step beyond and modified the ALiAladdin V chipset, in that
> the flawed tag RAM of the L2 cache (in Rev. E of the chipset) was disabled and
> replaced by their own 10 bit version. This results in a cacheable amount of 256 MB of
> RAM with the 512 kB L2 cache version and 512 MB cacheable with the (yet to be
> released) 1024kB L2 version of the P5A."
>
> Can anybody confirm this? If you have 256MB of RAM on your P5A/K6-II-based machine,
> would you be so kind to measure performance with 128MB and 256MB and post the results
> (and board revision) to the group? Perhaps that would clear things up. My planned
> upgrade path was to switch to the K6-III once it becomes really cheap and upgrade my
> RAM _then_ - making use of the on-die L2-cache, which is reported to cover all the
> RAM you can currently plug into the board. But if it is possible _now_ without a
> performance penalty, I'd get more RAM now.
>
> Greetings,
>
> Sven
>
there should be the possibility to confirm this by
using the program ctcm (what probably means ct
cache mes.) from the german mag ct. this is
available at "http://www.heise.de/ct/ftp/". May be
someone has already more than 128MB and uses still
the K6-2 can can run this and post the results ?? i
can't, because i have only 64MB and wanted to use
the same upgrade path as described above..)
btw: why are some people posting html code and no
simple text ??
good luck !
i'm looking forward to the results which may be
quite interesting for some people..
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