Confused about memory settings......

I have an ABIT AB9 Pro (WiFi) m/b with:
Intel C2D E6600 cpu
2Gb ( 2 x 1Gb) Crucial Ballistix DDR2 (pc2 6400) 800mhz ram

What are the best settings to get the best speed from this set-up?

I have built many pcs for myself and friends, and have overclocked all
of my own pcs, and I've not blown one up yet, but, I always get confused
by the memory settings, especially the bit where the memory speed is
doubled (DDR2) and is a ratio of the cpu speed?

In my current set-up I use a dram setting of 533 which gives me dram
clock speed of 400 (800 ddr) but where does the 533 come from? or what
is it a reading of or related to?And why in the Crucial memory spec
(above) are there two different speeds (6400 and 800)? where does the
6400 fit in?

I've got my current pc up to 3200mhz with the current settings (default
speed is 9 x 272 = 2400mhz) easily and it whizzes along nicely, but I'm
sure I'm not getting the best memory settings, and hence could get more
speed....

These are the current settings in my ABIT m/b bios....
========================
Screen = OC Guru:

External clock = 400mhz (options = various)
Multiplier = 8 (options = various)
CPU speed = (400 x 8) = 3200mhz
NB strap cpu as = psb1066 (options =by cpu, psb1066, psb533, psb800)
DRAM spec (cpu:dram) = 533 (options = by spd, ddr2 533, ddr2 667, ddr2 800)
Est new dram clock = 400mhz (ddr2 – 800)
PCI Express clock = 100mhz
CPU core Voltages = 1.3250v (options = various 1.3250v)
DDR2 voltage = 2.00v

Screen = advanced bios features:

CPU featu -
Thermal control = enabled (options = enable or disable)
Limit CPUID maxval = disabled = (for WINXP)
CIE function = disabled = (options = auto or disabled)
Execute disable bit = enabled (options = enabled or disabled
Virtualisation technology = disabled (options = enabled or disabled)
E1ST function = disabled (options = enable or disable)

Screen = advanced chipset features:

Dram timing = by spd (options = by spd or manual)
Cas Latency (tcl) = auto (options = auto or 3 to 6)
Ras# to Cas delay (tRCD) = auto (options = auto or 1 to 15)
RAS# precharge (tRP) = auto (options = auto or 1 to 15)
Precharge delay (tRAS = auto (options = auto or 1 to 31)
Command rate = auto (options = auto or 2T or 1T)
Refresh cycle time (tRFC) = auto (options = auto or 1 to 63)
==========================

What memory timings should I use in the advanced chipset bios screen?
and what memory settings should I use in the OC Guru screen.

Any info / explanations gratefully received, thanx...

8-)

pjgtech wrote:
I have an ABIT AB9 Pro (WiFi) m/b with:
Intel C2D E6600 cpu
2Gb ( 2 x 1Gb) Crucial Ballistix DDR2 (pc2 6400) 800mhz ram

What are the best settings to get the best speed from this set-up?

I have built many pcs for myself and friends, and have overclocked all
of my own pcs, and I've not blown one up yet, but, I always get confused
by the memory settings, especially the bit where the memory speed is
doubled (DDR2) and is a ratio of the cpu speed?

In my current set-up I use a dram setting of 533 which gives me dram
clock speed of 400 (800 ddr) but where does the 533 come from? or what
is it a reading of or related to?And why in the Crucial memory spec
(above) are there two different speeds (6400 and 800)? where does the
6400 fit in?

I've got my current pc up to 3200mhz with the current settings (default
speed is 9 x 272 = 2400mhz) easily and it whizzes along nicely, but I'm
sure I'm not getting the best memory settings, and hence could get more
speed....

These are the current settings in my ABIT m/b bios....
========================
Screen = OC Guru:

External clock = 400mhz (options = various)
Multiplier = 8 (options = various)
CPU speed = (400 x 8) = 3200mhz
NB strap cpu as = psb1066 (options =by cpu, psb1066, psb533, psb800)
DRAM spec (cpu:dram) = 533 (options = by spd, ddr2 533, ddr2 667, ddr2 800)
Est new dram clock = 400mhz (ddr2 – 800)
PCI Express clock = 100mhz
CPU core Voltages = 1.3250v (options = various 1.3250v)
DDR2 voltage = 2.00v

Screen = advanced bios features:

CPU featu -
Thermal control = enabled (options = enable or disable)
Limit CPUID maxval = disabled = (for WINXP)
CIE function = disabled = (options = auto or disabled)
Execute disable bit = enabled (options = enabled or disabled
Virtualisation technology = disabled (options = enabled or disabled)
E1ST function = disabled (options = enable or disable)

Screen = advanced chipset features:

Dram timing = by spd (options = by spd or manual)
Cas Latency (tcl) = auto (options = auto or 3 to 6)
Ras# to Cas delay (tRCD) = auto (options = auto or 1 to 15)
RAS# precharge (tRP) = auto (options = auto or 1 to 15)
Precharge delay (tRAS = auto (options = auto or 1 to 31)
Command rate = auto (options = auto or 2T or 1T)
Refresh cycle time (tRFC) = auto (options = auto or 1 to 63)
==========================

What memory timings should I use in the advanced chipset bios screen?
and what memory settings should I use in the OC Guru screen.

Any info / explanations gratefully received, thanx...

8-)

For the arithmetic, you start with the processor.
E6600 2.4GHz core/ FSB1066 / 4MB cache.

The front side bus (FSB) on the processor is quad pumped, meaning
that four data items are transferred per clock cycle. So the CPU
input clock is implied by the FSB value.

1066
---- = 266MHz CPU input clock
4

The CPU input clock also feeds the memory clock synthesizer. That
means, when you overclock the CPU, the memory is overclocked too.

Your settings above, say you've set the CPU input clock to 400.
To work out the effect this has on the memory subsystem, you use ratios.

400
--- * "DDR2-533 setting" == effectively_a_DDR2-800_setting
266

So, your choice of the DDR2-533 setting, used in conjunction with
that particular amount of input clock overclocking, results in the
memory running at DDR2-800. Now, the timing values used by the
BIOS, might be consistent with the original choice of DDR2-533,
which is why you want to correct the timing values manually,
if they're tighter than they're supposed to be.

In terms of the "DDR" in the memory name, that is dual data rate.
It means two data items are transferred per clock cycle. If the
memory is referred to as "running at DDR2-800", then we'd know
the memory bus clock is 400MHz. That bit of info comes in handy when
reading a CPUZ screen, as the memory display may be showing the
"clock" value, rather than the "transfer rate". So don't panic
if something seems to be off by a factor of 2.

I recommend CPUZ, as a quick means in Windows, of verifying your
settings. For example, when it is showing you the contents of
the memory SPD tables, it will be showing you values for Tcl,
Trcd, Trp, and Tras, at certain choices of transfer speed.
Those would be the settings you might want to use at your new
memory transfer rate of DDR2-800. (It all depends on whether
the SPD defines table values at DDR2-800. If it does not, then
you'd have to rely on the values announced in the product
advertisement, as a source of the correct values.)

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

Another way to do it, which won't wear out any brain cells, is
to set your system to nominal settings, then use CPUZ to show
the currently running timing values.

If you left the input clock at 266MHz for FSB1066, giving
2.4GHz core, then go to the memory subsystem and set it
to "DDR2-800" setting, and "timing by SPD", then when you
visit CPUZ in Windows, the currently running values for
Tcl, Trcd, Trp, and Tras, would be the ones to use for later
adventures with an effective DDR2-800 operating speed.

You can compare that to the information offered in an advertisement.
For example, 4-4-4-12 is shown here for the Ballistix at DDR2-800,
at a voltage of 2.0V (which is 0.2V above the nominal 1.8V operating
voltage). Command rate won't be specified, as that is as much
a system issue, as an issue for the stick itself. The parameter
order for the 4-4-4-12 is CAS-tRCD-tRP-tRAS in the advert. The
BIOS screen is not typically printed in the same order, so be
careful.

http://www.newegg.com/Product/Produc...82E16820148203

Next, you could go back to your overclock settings. 400MHz
CPU input clock, "DDR2-533" memory setting (effectively DDR2-800),
then copy Tcl, Trcd, Trp, and Tras manually into the BIOS
memory setup, just like you saw them in CPUZ (or the advert).

Command rate is a bus loading thing. 2T means the address is passed
for two cycles, giving more setup time to the memory. It compensates
for the Northbridge not being able to drive heavy loads well. At
one time, such a setting was only needed when four sticks were
present, and two sticks in dual channel config might have survived with
a 1T setting. But with really high effective transfer rate choices
for memory, even with two sticks in dual channel, sometimes 2T is
needed. Or it could even be, that a chipset only ever operates at
2T, and has no mechanism to report that fact. This might be a parameter
I test without booting into Windows, such as testing with memtest86+
from memtest.org or booting a Linux LiveCD such as Knoppix or Ubuntu.
You don't want to corrupt your Windows boot disk, by booting
with overly optimistic memory settings. Perhaps Command Rate
1T is just too tight. I don't know the right answer to this.

A number of the settings could be affected by the "ratio" thing,
but some of them might not be as critical as say a memory timing
value like Tcl. But you do want to be aware, that the automatic
option in the BIOS, may not always work out the correct values
for overclocked system components. So the above description, is
just a skeleton review of the issue. It would take me a lot of
experimentation (and finding a utility better than CPUZ), to
do everything just right.

So when the memory gets overclocked, the parameters used by the
BIOS may not be the correct ones. And this is why overclocking
is an empirical exercise, where the operator must always be
vigilant for stupid BIOS mistakes or incorrect settings.

Each BIOS can be designed differently, and it could be that
there is a BIOS out there that uses "real" settings instead
of "effective". That is why a copy of a program like CPUZ
is so useful, because it can help you understand the things
the BIOS does well, and the things the BIOS is clueless about.

For example, on my current motherboard and current BIOS revision,
my BIOS won't even set the Tcl, Trcd, Trp, and Tras according to
the values set in the BIOS screen :-( So double checking, and
careful testing with "safe" test cases (memtest86+ or a LiveCD
boot disk), before booting into Windows, is always a good idea.
You want your system to show it is bootable and not corrupting
things, before you boot back into Windows (and use CPUZ for
another look).

As an overclocker, you should always have a backup of your boot
disk available to you. If the boot disk is ever corrupted by
one of your experiments, you want to be able to restore it
without a lot of work. It doesn't happen as much as it used
to, but it can still happen.

HTH,
Paul

Paul, thanx for all that useful info....

Not sure I understand it all, but most of it is sinking in!

What about the pc2 6400 bit in the crucial ballistix spec for these
memory sticks, where does the 6400 bit come from?

Also, I have the pc set up (in the bios) as 8 x 400 giving me 3200 cpu
speed, but cpuz shows the cpu speed as 3600? (with 450 x 8 figures) The
pc still works ok though.

Also, to measure temperatures, i use the bios info, and core clock, and
speedfan and an nvidia utility and they all seem to show different cpu,
m/b, gfx card and case temperatures, so I'm never sure which one to
believe? Is there one utility you would recommend.

Thanx again for the info...

8-)

Screen = advanced bios features:

CPU featu -
Thermal control = enabled (options = enable or disable)
Limit CPUID maxval = disabled = (for WINXP)
CIE function = disabled = (options = auto or disabled)
Execute disable bit = enabled (options = enabled or disabled
Virtualisation technology = disabled (options = enabled or disabled)
E1ST function = disabled (options = enable or disable)

Paul, sorry forgot to add, I presume that I'm correct in disabling most
of the cpu throttling stuff on the above bios screen, as this just slows
things down as far as I know?

pjgtech wrote:
Paul, thanx for all that useful info....

Not sure I understand it all, but most of it is sinking in!

What about the pc2 6400 bit in the crucial ballistix spec for these
memory sticks, where does the 6400 bit come from?

Also, I have the pc set up (in the bios) as 8 x 400 giving me 3200 cpu
speed, but cpuz shows the cpu speed as 3600? (with 450 x 8 figures) The
pc still works ok though.

Also, to measure temperatures, i use the bios info, and core clock, and
speedfan and an nvidia utility and they all seem to show different cpu,
m/b, gfx card and case temperatures, so I'm never sure which one to
believe? Is there one utility you would recommend.

Thanx again for the info...

8-)

DDR2-800 is 400MHz clock times 2 transfers per clock cycle.
The 800 is megatransfers per second.

The DIMM is 8 bytes wide. Multiply DDR2-800 by 8 to get PC2-6400 in
units of megabytes/second. So the memory has 6400MB/sec of
transfer bandwidth, based purely on the memory bus limitation.

The CPU multiplier can change, if the processor supports EIST and
EIST is enabled. AMD has a similar feature in Cool N' Quiet.
What should happen, is the frequency should remain fixed, and
the multiplier gets changed, as well as the Vcore voltage
setting. EIST works in response to computing load, so if Windows
is idle, then the multiplier could get cranked down. Disabling
EIST in the BIOS, should cause the multiplier to remain at
the high value under all circumstances. If EIST is enabled,
maybe the multiplier will vary between 6 and 9 or so.

So I cannot honestly say where the "450" number has
come from. That part doesn't make sense. But the range of
multiplier values should be a function of the processor.
The processor is nominally 266 * 9 = 2400MHz. Nine would be
the highest multiplier supported, as far as I know.

So where did the 450 come from, for a clock setting ?
Is it bogus or real ? Does other information in the CPUZ
output, reflect 400MHz as the BIOS choice, or 450MHz ?
For example, the memory would have too high a setting, if
450MHz was the actual input clock choice. The memory
would be operating above DDR2-800 effective.

Maybe the 450MHz is an estimate of the maximum value ?

Paul