A message from Crucial

  • Thread starter Thread starter da_test
  • Start date Start date
I just found something else that quickly detects memory problems.
Open an avi file in virtualdub, hold down the shift key and drag the
pointer.
It should snap to key frames. Progress thru the avi should be
smooth. With my memory timings a little too aggressive,
I got hiccups and the avi display cleared to grey screen.

I'm giving prime95 a try now.

If you want to really pound the memory and do nothing else with the system,
it's recommended to bump the priority up a touch... under Advanced/Priority
try 8 or 9.
 
Sorry?
Prime95 does not "test lots of RAM". From the readme :
" SETTING AVAILABLE MEMORY
The P-1 factoring step prior to running a Lucas-Lehmer test is more
effective if it is given more memory to work with. However, if you let
the program use too much memory then the performance of ALL programs
will suffer. The good news is that 98% of the time the program uses
less than 8MB. In fact, the program will work just fine if you instruct
the program to use only 8MB or less."
etc ...

Run it and see. The Torture Test ran up to 900MB on my 1GB system the last
time I looked. I wonder if the para you quote is either out of date or
applies to everything but the Torture Test... IOW the real work. In that
respect, note that the Torture Test runs with a low priority on recent
versions, so possibly they shuffled things around without updating the
docs.
 
da_test said:
Secondly, as I mentioned in another post in this thread,
in my bios SPD seems related to interleave only,
unless I'm misunderstanding something - but I don't
think I am. I checked the chipset values using wpcredit.
Dave

Why do you think that's the case? The SPD has nothing to do with
interleave. The interleave is a factor that the system itself sets
through the BIOS & chipset, but it runs the RAM at whatever settings you
specified whether it's interleaved or not. Interleaving is outside the
control of each individual DIMM, it works at the memory bank level.

Yousuf Khan
 
George said:
(snip)

Run it and see. The Torture Test ran up to 900MB on my 1GB system the last
time I looked. I wonder if the para you quote is either out of date or
applies to everything but the Torture Test... IOW the real work. In that
respect, note that the Torture Test runs with a low priority on recent
versions, so possibly they shuffled things around without updating the
docs.
Ah, I see. I stand corrected.

The thing is I run P95 23.8.1 24/7, and have been for seven years or so
as a permanent fixture and long-term stability check and also as part of
GIMPS (M34406129 ATM), and have never run any torture test - just
factoring integers, so I missed that.
(If you want to convert a Mersenne integer to decimal and boggle at the
size use Mprint, http://www.apfloat.org/apfloat/ )

Apologies to all and thanks for putting me right.

Regards
 
Why do you think that's the case? The SPD has nothing to do with
interleave. The interleave is a factor that the system itself sets
through the BIOS & chipset, but it runs the RAM at whatever settings you
specified whether it's interleaved or not. Interleaving is outside the
control of each individual DIMM, it works at the memory bank level.

Yousuf Khan
Hello Yousuf,
it's only because it's an option in my Bios.
Options for "bank interleave" are 4-way, 2-way, "off" or
"by spd"

When "by spd" is chosen, 4-way is used. I checked that
using pcredit. However, choosing that setting does not alter
the memory timings in the chipset registers.
They are still selected based on two other bios settings,
"cas latency" and "Dimm memory speed"

In other words there isn't a way in my bios to set cas latency
or dimm memory speed based on any info the RAM supplies;
rather, like most Bios' they have a default based on the
most conservative; ie. cl3 and 6-3-3.

regards,
Dave
 
Ed, a couple of things, I've never had much luck with memory testers.
If I set the timing aggresively, I will/have errors in Windiws.
But memtest86+ never finds a problem.

Secondly, as I mentioned in another post in this thread,
in my bios SPD seems related to interleave only,
unless I'm misunderstanding something - but I don't
think I am. I checked the chipset values using wpcredit.
Dave

Prime 95 works best for me, I mainly use memtest86 when building a new
system, if you can't pass at least a few passes you know something is
out od wack. ;p

Not sure, I've only had one or two boards where the bios let you change
interleave and it was a separate option, check the mobo manual.

Ed
 
In other words there isn't a way in my bios to set cas latency
or dimm memory speed based on any info the RAM supplies;
rather, like most Bios' they have a default based on the
most conservative; ie. cl3 and 6-3-3.

regards,
Dave

Maybe it's time to upgrade the mobo? ;p
Ed
 
Why do you think that's the case? The SPD has nothing to do with
interleave. The interleave is a factor that the system itself sets
through the BIOS & chipset, but it runs the RAM at whatever settings you
specified whether it's interleaved or not. Interleaving is outside the
control of each individual DIMM, it works at the memory bank level.

You are soooo stuck in the '80's, YK.

There *are* banks in them there drams, son. And they can be configured via
MSRs/EMSRs that exist inside the drams...

/daytripper (Better start reading some recent vintage dram specs ;-)
 
Why do you think that's the case? The SPD has nothing to do with
interleave. The interleave is a factor that the system itself sets
through the BIOS & chipset, but it runs the RAM at whatever settings you
specified whether it's interleaved or not. Interleaving is outside the
control of each individual DIMM, it works at the memory bank level.

Not sure what you're saying there but interleaving, as it applies to modern
DIMMs, works at the memory chip level - all SDRAM chips >16Mb used in PCs
have 4 banks right on the chip; the 16Mb chips had 2 banks. Years ago,
Dave T told me that there was a plan to go to 8 banks with 256Mb[IIRC]
chips but I guess it fell victim to backwards compatibility with chipsets,
chipset cost... or maybe even inertia.

The DDR SPD doc I have, from IBM, is old and maybe out of date but it seems
to show that there are fields in SPD for both "physical banks" on the
module, for which the term rank is preferred now, and the SDRAM device
banks. In fact the device banks field caters for going to 255 banks;
oddly, the "rank" fields cater for having different sizes of memory on each
side of a module and even different sized and width chips.

When you set the "interleave" in BIOS Setup it's the control on device
banks which you are setting: 0/off, 2 or 4. Off just runs the chips with
auto-precharge. The different chipsets have different ways of handling
this device interleave of banks: on their better chipsets, Intel has
generally allowed all 4 banks on every rank to be kept open simultaneously
and favored an idle timer for precharge; VIA has generally allowed only 2
ranks to have open banks simultaneously and precharged when an address went
to a 3rd rank. In the absence of docs, I've no idea how nVidia handles
things nor AMD.s 64s but I haven't tried to ferret that out.

BTW, I believe that device banks is/was one of Rambus' infringement claims
against SDRAM - their DRDRAM devices had 32 banks of which 16 could be open
simultaneously - the sense amps were shared between adjacent banks. They
also proposed changing to a different scheme for their later DRDRAM, with 4
"independent" banks, just like SDRAM, but I beleive it was abandoned due to
lack of interest by chipset mfrs, notably Intel.
 
Ah, I see. I stand corrected.

The thing is I run P95 23.8.1 24/7, and have been for seven years or so
as a permanent fixture and long-term stability check and also as part of
GIMPS (M34406129 ATM), and have never run any torture test - just
factoring integers, so I missed that.

Wow, your system gets a real workout then - care to share its specs and, of
course brand/type of memory?
(If you want to convert a Mersenne integer to decimal and boggle at the
size use Mprint, http://www.apfloat.org/apfloat/ )

Thanks.
 
George said:
Wow, your system gets a real workout then - care to share its specs and, of
course brand/type of memory?
It all really started when I bought a FIC VA-503+, stuck a P166MMX on it
and discovered that it overclocked amazingly well - 2.5x100MHz,
absolutely solid with P95 at all times, for 18 months. Then I played
with a K6-2, K6-2+ etc etc, until meltdown occurred a year ago.

The replacement system had to be bought in a hurry - a quick but rather
boring Asus a7n8x-x, XP2800 and 2x256 + 1x512MB PC3200.
Even though it's an unlocked XP2800 this a7n8x-x does not like 200 MHz
FSB and all my overclocking attempts have so far been fruitless ...

.... until a couple of hours ago that is, when I learnt in
alt.comp.hardware.overclocking.amd, of a modded BIOS (1010-XMOD2_2T) for
the a7n8x-x that lets it function at 200MHz FSB, and by golly it does
too!
(Warning - slight niggles - F1 key would not exit Awdflash, reboot
resulted in power cycling, CMOS had to be cleared, but only once and OK
since)
For the first time now, it is purring at 10.5x200MHz, std voltages, and
p95 is purring too. I haven't yet started twiddling voltages etc, but
w98se works fine with 11x200Mhz, std volts, even though p95 falls over
sooner or later.
But this is early days - very encouraging early results and I'm
optimistic that I can get this system much much quicker than it is,
and I hope maybe soon to compete with these XP-M owners who post and
boast about the awesome speeds that they obtain.
Time to play. (dreams .... 2700MHz ... finding Mersenne prime ...)

Regards
 
Sorry?
Prime95 does not "test lots of RAM". From the readme :
" SETTING AVAILABLE MEMORY
The P-1 factoring step prior to running a Lucas-Lehmer test is more
effective if it is given more memory to work with. However, if you let
the program use too much memory then the performance of ALL programs
will suffer. The good news is that 98% of the time the program uses
less than 8MB. In fact, the program will work just fine if you instruct
the program to use only 8MB or less."
etc ...

Hmmmm I never set anything and P95 sucks up all the free ram (in the
Lots of Ram test), and from then on it seems like anything needing more
ram is sent crying to the swap file.
 
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