Wrote a small article on chipset strap etc

[Eastcoasthandle]

To find the correct strap values let's put what tony said in formula:
Ram_Freq=2*FSB_freq*north_multi/mem_div
where:
Ram_Freq is DDR freq (DDR clock*2, this explains the "2" term in the right)
FSB_freq is the base FSB freq (so for 1066 FSB_freq=1066/4=266)
north_multi give us the Northbridge frequency. We have:
533_strap -> north_multi = 3
800 strap -> north_multi = 2
1066 strap -> north_multi = 3/2
1333 strap -> north_multi = 6/5
Note for 533_strap tony speaked of 6 multi, but it referred to FSB_freq/2, so i'm saying the same thing.
mem_div can be set to the following values:
2
3/2
6/5
1
So for a 266 FSB we can have the following "mem ratios":
533_strap-> 800, 1066, 1333, 1600
800_strap-> 533, 711, 889, 1066
1066_strap-> 400, 533, 667, 800
1333_strap-> 320, 427, 533, 640
Because P5W uses only 800_strap and 1066_strap for 1066 FSB we have the following:
Auto -> it depends on RAM spd
400 -> 1066_strap
533 (1:1) -> can be either 800_strap or 1066_strap (but i think p5W uses 1066 strap)
667 -> 1066_strap
711 -> 800_strap
800 -> 1066_strap
889 -> 800_strap
1067 -> 800_strap

Now based on the strap table above, as tony said, we can have 1:1 with 1333 strap too, in this case the FSB at which the north would be overclocked is:
FSB=400/(6/5)=333, so if the north has its wall at 375 FSB with 1066 strap in this case the wall would be shifted at 469...

Thanks for the info.

[Eastcoasthandle]

Almost:

533, 667, 800, should all be on the 1067 strap (stock strap for Conroe)

400, 711, 889, and 1067 would be on the 800 strap which would overclock the memory controller (MCH).

caate and RyderOCZ, thanks for the info

[astaris]

Already done some, using them internally..IE they will not be released as of yet

I hope that when available your modded bios will let set the strap and the memory ratio with two different bios entries and that the available mem_ratios will be linked dinamically to the strap you set.
Anyway great findings tony.

[shine121]

very nice info , thanks tony and astaris
but i still have some stupid terminology to ask?

1. what's the term "strap" mean? FSB of NB?

2. why 533_strap how does it come out to north_multi = 3
the formula "Ram_Freq=2*FSB_freq*north_multi/mem_div" doesnt show the relation between strap and north_multi?

If i ask the wrong question then just tell me shut up or to the google, thanks

[astaris]

very nice info , thanks tony and astaris
but i still have some stupid terminology to ask?

1. what's the term "strap" mean? FSB of NB?

2. why 533_strap how does it come out to north_multi = 3
the formula "Ram_Freq=2*FSB_freq*north_multi/mem_div" doesnt show the relation between strap and north_multi?

If i ask the wrong question then just tell me shut up or to the google, thanks

The term strap refers to a setting in a northbridge register (north_multi) that in the available bioses depends on three factors:
1) Nominal FSB of the processor (i.e. 533, 800 and so on)
2) Ram ratio selected (i.e. DDR2 533, 667 and so on)
3) The bios programmers team, when a given ram ratio is available through different north_multis
About the second question we have:
Northbridge_frequency=FSB_freq*north_multi
For a chipset strap equal to 533 the nominal FSB_freq is 133, so in order to have the northbridge frequency equal to its nominal value (400), the north_multi has to be 3.

[nooh]

May help you guys, I posted it on the OCZ support forums.

http://www.bleedinedge.com/forum/showthread.php?t=22297

I will add how it effects overclocking etc next. For now it explains ram ratio's, strap and chipset overclocking.

T

Good stuff tony, you the man

[Batman!]

I was still a bit confused, but thanks alot of astaris, you put it in terms which I understood even more easily then tony's GREAT article.

I think I got it.

Much thanks.

[Eastcoasthandle]

Example...this is just and example
At stock speed E67 Corsair PC6400Pro

800 strap @ Dram Freq 899, MCH @ 1.60 Mem Voltage 2.00V
Using Everest
Mem Read 7766
Mem Write 4821
Mem Copy 5443
Mem Latency 53.6
SPI 18.781

1067 Strap @ 800, MCH 1.60V Mem Voltage 2.00V
Using Everest
Mem Read 7518
Mem Write 4820
Mem Copy 5371
Mem Latency 56.8
SPI 18.812

I didn't OC because I wanted some sort of visual to get an idea of how each strap will do. I assume that once you OC the tighter NB timings on the 800 (711, 889, 1067) strap will reduce your OC considerably (if I am understanding this right) vs. using the 1067 strap (533, 667, 800).

Personally I thought the the 1067 strap would have yieled better performance but I guess it's correct to say that the 800 strap does in fact some sort of OC/tighter timing for the NB.

[shine121]

The term strap refers to a setting in a northbridge register (north_multi) that in the available bioses depends on three factors:
1) Nominal FSB of the processor (i.e. 533, 800 and so on)
2) Ram ratio selected (i.e. DDR2 533, 667 and so on)
3) The bios programmers team, when a given ram ratio is available through different north_multis
About the second question we have:
Northbridge_frequency=FSB_freq*north_multi
For a chipset strap equal to 533 the nominal FSB_freq is 133, so in order to have the northbridge frequency equal to its nominal value (400), the north_multi has to be 3.

thanks for the info, now i think i got it.

[dinos22]

looks like Gigabyte DS3 mobo is one of those mobos that's with a lower strap setting for 1:1 mode to enhance its performance at stock

965 works just the same way as 975 which works just the same as 955 etc etc etc.

965 is a more overclockable chipset than 975, so where the 975 stops with the CPU fsb at 370 ish the 965 is stopping at 400 or so unless you manipulate the strap on the chipset to lower its overall clock.

I can not stress the following enough to you guys.

Many of you are blaming ram for poor overclocking etc when infact its the chipset that is holding you all back. On intel systems you are overclocking 3 things similtaniously, the CPU, the chipset and the memory, all 3 things have to be in balance to get stability.

Some of these huge 500+fsb overclocks are purely managed on the back of very high chipset voltages which are needed to force the chipset to manage huge overclocks. Some people do get lucky and get a NB that clocks like a god...they do exist just as golden CPU's do and GPU's.

Also the wierd memory ratio's (1067 888 712 etc) are the product of chipset strap manipulation, you all have to be aware that this alters how the chipset will overclock and how it controls the memory. It usually will not clock as well although even at lower clocks the memory performance may be better. Also as I mentioned in the guide im already seeing boards setting the 800 strap for 533(1:1) mode with end users complaining they can not do 400fsb 1:1 for DDR800 on their ram so the ram must be faulty. Issue is the ram does ddr800 fine in 667 or 800 mode as the chipset is back at normal clocks and can control the memory a lot easier.

>>>>Tony great work on this write up

I can see that you've put a lot of thought into this and it certainly helps me marginally begin to understand this beast of Intel chipset :thumbs:

To finish

If you want to make sure your ram is ok test ONLY with 667 or 800 mode, this will limit the FSB the CPU may do but it will prove if the memory can do the speeds you are looking to push it to without the NB limiting you.

If you find you can not overclock at all well in 533(1:1) mode on your motherboard please try 667 or 800 and see how the CPU and ram overclocks, this will prove if the board is setting a lower strap for 1:1 mode to enhance its performance. Another way to help the NB in an overclocked state is to losen the memory timings, even though they are lose it may still end up being faster as the NB is running at a much faster speed on the lower strap ratio.

You may feel the ram will not do its rated speeds, this will probably NOT be the case...the issue will be the NB is overclocked and will not run the ram at the speeds you want it to.

So the saga continues...how to make a board ubber fast at stock speeds so reviews look awesome

Now you all seem to have a reasonable idea of how straps work i will show you how the motherboard manufacturers manipulate them in bios to make the boards work faster than the competition in reviews.

Using a conroe, which has 1066 strap and 267fsb we all know that 1:1 is 533 on the memory. Now if you want your board to work around 5% faster all you do is lower the strap but keep the ram ratio at 1:1.So you force the strap on the clockgenerator to 1066 but you trick the NB to run on the 800 strap in 400 mode.
On a 965 board this would allow 400fsb+ in theory on the CPU but there is no way the NB would run on the high 800strap internal multi and high bus speed without luck in you gettting awsome silicon and a ton of voltage.
At 267fsb on the CPU though the NB stands a good chance of working just fine, its moderately overclocked but not to stressed....and you gain 5% or so performance from the memory which transaltes into more FPS in game benches.

This is why when I ask you to test ram you need to do it with the 667 or 800 memory ratio, i already know 712,888 and 1067 are 800 strap, what i don't know is what 533 is latched too, as it could easy be off the 800 strap to improve performance at low clocks 1:1.

I think it now makes a bit more sense why you told me that RAM which i couldn't even boot with the system would run perfectly normally with 800 mode (i think heheh)

just some info for others i've been testing some Fatbody D9 RAM on Gigabyte DS3 (965 chipset) and the RAM was completely struggling 1:1 and was unstable just by going a simple 10MHz over the stock FSB. Not only that buy after clearing cmos and starting with these Fattys the board will just refuse to start.........I would only be able to gain control once i put g.skill HZ stick.....apply 2.0vdimm, save, shutdown, changeover sticks and boot up.

Gigabyte DS3 has the following RAM ratios in bios
2.0 > 533
2.5 > 667
3.0 > 800
2.66 > 710
3.33 > 888
4+ > 1067

However after Tony's suggestions to try 800MHz (3.0 RAM divider in bios) i've discovered that that RAM can operate at 1.8v without any problems whatsoever. In fact this is how it scaled:
1.8vdimm 4-3-2(3inwindows)-9-Auto ~ 355MHz
1.9vdimm 4-3-3-9-Auto ~ 380MHz
2.0vdimm 4-3-3-9-Auto ~ 405MHz
2.1vdimm 4-3-3-9-Auto ~ 428MHz
2.2vdimm 4-3-3-9-Auto ~ 452MHz
vdimm past 2.2 was acting funny




so if i'm not wrong the bios design is contributing to a lot of problems people are having with certain room and bootup problems


why puzzles me now is that my other sticks which are G.Skill HZ D9GMH we all know and love work perfectly 1:1 with the same setup.

Tony can you unravel this little mistery for us please

[Rare1]

Great read. Thank you very much

[remorema]

tkx to all users for sharing...

really hope that asus releases a bios where more memory timings, and 1333 strap are available.

the thing really anoying me, is my p5wdh can do 400 fsb 1:1 only with spd enabled.

heheh, after years of reading my first post

[Eastcoasthandle]

tkx to all users for sharing...

really hope that asus releases a bios where more memory timings, and 1333 strap are available.

the thing really anoying me, is my p5wdh can do 400 fsb 1:1 only with spd enabled.

heheh, after years of reading my first post

[Eastcoasthandle]

Example...this is just and example
At stock speed E67 Corsair PC6400Pro

800 strap @ Dram Freq 899, MCH @ 1.60 Mem Voltage 2.00V
Using Everest
Mem Read 7766
Mem Write 4821
Mem Copy 5443
Mem Latency 53.6
SPI 18.781

1067 Strap @ 800, MCH 1.60V Mem Voltage 2.00V
Using Everest
Mem Read 7518
Mem Write 4820
Mem Copy 5371
Mem Latency 56.8
SPI 18.812

I didn't OC because I wanted some sort of visual to get an idea of how each strap will do. I assume that once you OC the tighter NB timings on the 800 (711, 889, 1067) strap will reduce your OC considerably (if I am understanding this right) vs. using the 1067 strap (533, 667, 800).

Personally I thought the the 1067 strap would have yieled better performance but I guess it's correct to say that the 800 strap does in fact some sort of OC/tighter timing for the NB.

2.93Core, 800 Strap @ 976 Dram Frequency, MCH 1.65V Mem Voltage 2.20V
Using Everest
Mem Read 8458
Mem Write 5252
Mem Copy 5938
Mem Latency 49.1
SPI 17.250
Memory Clock 488.7 which I believe is 1/2 speed @ 3:5

[H0RM0NE]

From: The definitive guide to Intel chipset/memory over clocking.

All Intel chipsets work the same, starting from 845 up. The clockgens are based on the chipset straps so work the same way pretty much

Tony et al, First off THANKS!!!

My Question is will these same straps/ratios work the same on the 680i chipsets (C55XE / MCP55XE and C55 / MCP55)?

# FSB 1333/1066/800
# DDR2-1200*/800/667/533 (* for SLI-ready memory with EPP)

Or do we need a "The definitive guide to nvidia chipset/memory over clocking."...??? (My guess is yes the same applies)
Thanks.

[luihed]

Tony, do you know where I can find this guide now? I cant find it anymore at Bleedingedge.... thanks....

[FlyBoyGeo]

Tony, do you know where I can find this guide now? I cant find it anymore at Bleedingedge.... thanks....

Ditto....I was just looking for it myself.

[hawtrawkr]

Ditto....I was just looking for it myself.

let me join the looking for it too club.

[crazyea]

There ya go boys.

http://www.bleedinedgesupport.com/oc...ad.php?t=22297

[Shnorque]

so I just finished reading this inbetween uni lectures this mourning and perhaps somebody could clarify a few things for me.

1. By default a conroe would use 1066 strap?
2. Using different mem dividers can change the NB strap without changing the CPU strap? (this is really what I would like to know...)
3. After overclocking your CPU FSB to a certain point the motherboard automatically selects a different strap (1333?) which increases FSB but relaxes ram timings?

Thanks for any help.

[revenant]

so can anyone else not get to the link? I signed up and everything.. it says I don't have sufficient privies.. like I am trying to edit the post or something.. anyways..

[crazyea]

I posted the correct link two posts up. they changed the url.

used to be bleedingedge.com, now it's bleedingedgesupport.com

[hawtrawkr]

There ya go boys.

http://www.bleedinedgesupport.com/oc...ad.php?t=22297

ty for the link

[mXpS]

There ya go boys.

http://www.bleedinedgesupport.com/oc...ad.php?t=22297

I think the site is down because the link doesn't work.

[RyderOCZ]

I think the site is down because the link doesn't work.

The site URL has changed again.

Correct Link: http://www.ocztechnologyforum.com/fo...ad.php?t=22297