Re: ddr1 memory

john wrote:
> i got the third stick of ddr1 memory.
> putting it in the system. i run a memtest.
>
> u see the cl is 2.5 not 3 which is no the stick.
> the bios is set to auto. should i change the bios to maual
> and change it back, or will it run ok with that setting.
> (run boinc on the system at 100%)
>
> stick is kingston valueram.
>

If the memory settings in the BIOS are "Auto",
and you add multiple sticks of memory, the BIOS
will do a good job of selecting settings to use.

If you set the BIOS to "Manual" and enter the
numbers yourself, then *you* are responsible
for selecting the right numbers to use.

To make an example

1) I have one stick of memory with CAS2.5
2) I have a second stick of memory with CAS3
3) My BIOS memory section is "Auto"

then the BIOS will set the memory controller to CAS3.
CAS3 is exactly what is needed for (2). CAS3 is
slower than the CAS2.5 in (1), so that stick is
happy also.

The settings selected apply to all memory sticks
at the same time. The computer doesn't feed
each stick different values. The sticks all
share the same hardware busses, so the
settings are shared values as well. The
BIOS tries to select settings slow enough,
so that the slowest of all the memory sticks
will be satisfied and run well.

HTH,
Paul

john wrote:
> this is the setting that the bios has set at boot time.
>
> 2.5-3-3-7
>
> from a memtest program.
>
>

If you had a stick with a rating of 3-3-3-8, then
the BIOS would have made a mistake. If all the
sticks are CAS 2.5 or CAS 2.0, then that would be
a good setting.

You'd really need to give a full description of each
stick. You can get details from CPUZ. Run the .exe.
Go to "About" tab. Select "Register Dump txt" and
it will make a text file with the results for your
computer.

http://www.cpuid.com/cpuz.php

*******
This is a selective snip from my cpuz.txt register dump.
The "DIMM" part, is what the DIMM is "advertising" as options.
The SPD chip on the DIMM, holds this timing table, and
CPUZ can read it out.

DIMM #1

Timings table
Frequency (MHz) 200 266 333
CAS# 3.0 4.0 5.0
RAS# to CAS# delay 3 4 5
RAS# Precharge 3 4 5
TRAS 9 12 15
TRC 12 16 20

Copy over each DIMM table. My second DIMM is the same as the first.

DIMM #2

Timings table
Frequency (MHz) 200 266 333
CAS# 3.0 4.0 5.0
RAS# to CAS# delay 3 4 5
RAS# Precharge 3 4 5
TRAS 9 12 15
TRC 12 16 20

The section above that, called "Chipset", shows what my BIOS selected as
operating conditions

Chipset

Northbridge VIA PT880 Pro rev. 00
Southbridge VIA VT8237S rev. 00
Graphic Interface AGP
AGP Revision 3.0
AGP Transfer Rate 8x
AGP SBA supported, enabled
Memory Type DDR2
Memory Size 2048 MBytes
Channels Dual
Memory Frequency 266.0 MHz (3:4) <----- 266*2 means DDR2-533 in my case
DRAM Interleave 4-way
CAS# 3.0 \
RAS# to CAS# 3 \___ BIOS is using 3-3-3-12, because
RAS# Precharge 3 / I forced it to do that :-)
Cycle Time (tRAS) 12 /
Command Rate 1T
*******

If you want comments on your particular settings, then
provide some info from the CPUZ register dump.

Paul

john wrote:
> this is the dump.
>
> Chipset
> ------------------------------------------------------------------------------
>
> Northbridge NVIDIA GeForce 6100 rev. A2
> Southbridge NVIDIA nForce 410/430 MCP rev. A3
> Memory Type DDR
> Memory Size 2560 MBytes
> Channels Single
> Memory Frequency 157.9 MHz (CPU/14)
> CAS# 2.5
> RAS# to CAS# 3
> RAS# Precharge 3
> Cycle Time (tRAS) 7
> Bank Cycle Time (tRC) 10
> DRAM Idle Timer 16
> Command Rate 2T
>
>
> Memory SPD
> ------------------------------------------------------------------------------
>
> DIMM #1
>
> General
> Memory type DDR
> Manufacturer (ID) Kingston (7F98000000000000)
> Size 1024 MBytes
> Max bandwidth PC3200 (200 MHz)
> Part number K
> Serial number 732698DC
> Manufacturing date Week 24/Year 07
>
> Attributes
> Number of banks 2
> Data width 64 bits
> Correction None
> Registered no
> Buffered no
> Nominal Voltage 2.50 Volts
> EPP no
> XMP no
>
> Timings table
> Frequency (MHz) 166 200
> CAS# 2.5 3.0
> RAS# to CAS# delay 3 3
> RAS# Precharge 3 3
> TRAS 7 8
>
>
> DIMM #2
>
> General
> Memory type DDR
> Manufacturer (ID) Kingston (7F98000000000000)
> Size 512 MBytes
> Max bandwidth PC3200 (200 MHz)
> Part number K
> Serial number 600FC249
> Manufacturing date Week 49/Year 05
>
> Attributes
> Number of banks 2
> Data width 64 bits
> Correction None
> Registered no
> Buffered no
> Nominal Voltage 2.50 Volts
> EPP no
> XMP no
>
> Timings table
> Frequency (MHz) 133 166 200
> CAS# 2.0 2.5 3.0
> RAS# to CAS# delay 2 3 3
> RAS# Precharge 2 3 3
> TRAS 6 7 8
>
>
> DIMM #3
>
> General
> Memory type DDR
> Manufacturer (ID) Kingston (7F98000000000000)
> Size 1024 MBytes
> Max bandwidth PC3200 (200 MHz)
> Part number K
> Serial number 64316877
> Manufacturing date Week 12/Year 06
>
> Attributes
> Number of banks 2
> Data width 64 bits
> Correction None
> Registered no
> Buffered no
> Nominal Voltage 2.50 Volts
> EPP no
> XMP no
>
> Timings table
> Frequency (MHz) 133 166 200
> CAS# 2.0 2.5 3.0
> RAS# to CAS# delay 2 3 3
> RAS# Precharge 2 3 3
> TRAS 6 7 8
>
>

OK, so that is likely an AMD motherboard where the processor
has a built-in memory controller. Sometimes, the BIOS drops
the clock rate, in accordance with the bus driving capabilities
of the AMD processor. If you use too many sticks in such a
computer, the memory bus is slowed down. Right now, it is running
DDR316 and using Command Rate 2T (instead of 1T), so would be
pretty slow.

To give an example, if you had an AMD board with a S754 processor,
there might be three memory slots. The most you'd want to use,
would be two slots, like slot one and slot three. Then, select
as large a DIMM as can be supported. Say, 2x1GB sticks. That
might represent the best compromise between speed and capacity.

Going back to your particulars -

The memory controller is 157.9MHz right now. x2 = DDR316

The AMD processor's memory controller is set up, to use
a clock value below the limit, so that there won't be a
problem. In another situation, the computer may have used
DDR333 in that situation, but the AMD clock logic has limited
granularity. (I think it might have something to do with the
core multiplier being odd or even or something like that.)

Anyway, you're running DDR316 2.5-3-3-7

Now, we look at what your DIMMs are advertising as their ratings.

1024MB 512MB 1024MB
<-- DIMM #1 -->|<----- DIMM #2 ---->|<----- DIMM #3 ---->
DDR333 DDR400 |DDR266 DDR333 DDR400|DDR266 DDR333 DDR400
Frequency (MHz) 166 200 |133 166 200 |133 166 200
CAS# 2.5 3.0 |2.0 2.5 3.0 |2.0 2.5 3.0
RAS# to CAS# 3 3 |2 3 3 |2 3 3
RAS# Precharge 3 3 |2 3 3 |2 3 3
TRAS 7 8 |6 7 8 |6 7 8

So the nearest setting to DDR316 in the DIMM tables, is DDR333. And
at DDR333, all sticks run 2.5-3-3-7, so the BIOS has done precisely
the right thing.

You can try pulling DIMM #2 (with all power off). Run the computer
with 2GB total memory.

If you download this Asus manual, this is a manual for an early S754
board with three slots. See "Table 1" on PDF page 21. It shows
a loading versus memory bus speed table. Line 18 in the table
suggests that two double sided DIMMs can run at DDR400, if plugged
into slot 1 and slot 3. If you remove your DIMM#2, the BIOS
should run your system at DDR400 3-3-3-8. (As all tables above are
rated at 3-3-3-8 at that speed.)

ftp://ftp.asus.com/pub/ASUS/mb/sock7.../e1529_k8v.pdf

I'm assuming this is a S754 system, and I'm not positive
that is the case. But if it was S939, there'd be four slots.

Paul

john wrote:
> i pulled the 512 and it is back to normal.
>
> so i guess the 512 is going bad.
>
> thanks.
>

No, the computer adjusts the clock rate, according
to bus loading. Three sticks of memory is a heavy
load for the bus, which is why it is using slow
settings.

By installing only two sticks, a higher clock speed
can be used. So your 2x1GB is a better way to run
the computer, than 2x1GB+512MB. 2x1GB would be the best
compromise between memory capacity and operating speed.

Paul

john wrote:
> ok, i will just have the 2- 1gb in.
> thanks.
>

These are the most important parts of your posted results.

Northbridge NVIDIA GeForce 6100 rev. A2
Southbridge NVIDIA nForce 410/430 MCP rev. A3
Memory Type DDR
Memory Size 2048 MBytes
Channels Dual
Memory Frequency 200.9 MHz (CPU/11)
CAS# 3.0
RAS# to CAS# 3
RAS# Precharge 3
Cycle Time (tRAS) 8
Bank Cycle Time (tRC) 11
DRAM Idle Timer 16
Command Rate 2T

You're running 200.9*2 = DDR400.
Timing is 3-3-3-8

Command Rate is 2T. I don't know if forcing
it to 1T would work or not. But that is the
only other obvious improvement you could make.
If you were to try forcing it to 1T, you'd
want to run memtest86+ to make sure it is
stable and error free. Don't boot into Windows,
if the memory settings are dodgy.

What command rate affects, is how many cycles are
used on the address/command bus, to pass a value.
2T means two cycles are used per item passed.
1T means only one cycle is used, and that is a
"tighter" setting. Sometimes setting to 1T,
breaks things, depending on the bus loading. The
S754 has two address/command buses, which is
why, with two sticks, there is a small chance
of being able to run Command Rate 1T. Usually,
by using slot 1 and slot 3, there is one stick
per address/command bus.

If you're happy with your current performance,
then leave the settings as is. They should be
quite stable, as listed in your above-provided table.

Paul

On Wed, 07 Jan 2009 12:27:27 -0500, Paul wrote:

> No, the computer adjusts the clock rate, according to bus loading. Three
> sticks of memory is a heavy load for the bus, which is why it is using
> slow settings.
>
> By installing only two sticks, a higher clock speed can be used. So your
> 2x1GB is a better way to run the computer, than 2x1GB+512MB. 2x1GB would
> be the best compromise between memory capacity and operating speed.

For my motherboard, I read that the DDR will drop to 333 if I use the
maximum 4gigs, which would be 1gig per each of the 4 slots. I am now
using 2x1GBs and 2x512MBs, which is using every slot, but I am still
running at 400.

ShadowTek wrote:
> On Wed, 07 Jan 2009 12:27:27 -0500, Paul wrote:
>
>> No, the computer adjusts the clock rate, according to bus loading. Three
>> sticks of memory is a heavy load for the bus, which is why it is using
>> slow settings.
>>
>> By installing only two sticks, a higher clock speed can be used. So your
>> 2x1GB is a better way to run the computer, than 2x1GB+512MB. 2x1GB would
>> be the best compromise between memory capacity and operating speed.
>
> For my motherboard, I read that the DDR will drop to 333 if I use the
> maximum 4gigs, which would be 1gig per each of the 4 slots. I am now
> using 2x1GBs and 2x512MBs, which is using every slot, but I am still
> running at 400.

There are three options:

1) two sticks running DDR400 Command Rate 1T
2) four sticks running DDR333 Command Rate 1T (BIOS auto preference)
3) four sticks running DDR400 Command Rate 2T (User adjustment and test...)

If those 512MB sticks happened to be single sided modules, then
that would reduce the bus loading slightly, and make (3) a
good prospect. If you use something other than the BIOS
default, you should test for stability. (Memtest86+/Prime95 or equiv)

Paul

On Wed, 07 Jan 2009 17:59:47 -0500, Paul wrote:

> There are three options:
>
> 1) two sticks running DDR400 Command Rate 1T 2) four sticks running
> DDR333 Command Rate 1T (BIOS auto preference) 3) four sticks running
> DDR400 Command Rate 2T (User adjustment and test...)
>
> If those 512MB sticks happened to be single sided modules, then that
> would reduce the bus loading slightly, and make (3) a good prospect. If
> you use something other than the BIOS default, you should test for
> stability. (Memtest86+/Prime95 or equiv)

My 512s *are* single-sided, but my BIOS are a stripped OEM version that
doesn't allow me to modify RAM settings.