Drive Strength Explained?

With the coming of the ATI xfire and the advent of 4 dimms @ 1t, I am hearing a lot of emphasis on drive strength tweaking.
This has been a setting that I have basically left at 7 on my NF4, and never even thought about. Can anyone give an intuitive explanation of it?

thx

I can give you the most basic explanation. Drive Strength is related with Vdimm, meaning the higher your Vdimm, higher your DRAM Drive Strength should be.

That's why you see all the people with UTT/BH5 based RAM running on a high Drive Strength.

All I know about Drive Strength is everytime I change it from auto it equals instant INSTABILITY, but my ram is toast so...no one noes

RedDragonXXX said:

I can give you the most basic explanation. Drive Strength is related with Vdimm, meaning the higher your Vdimm, higher your DRAM Drive Strength should be.

That's why you see all the people with UTT/BH5 based RAM running on a high Drive Strength.

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I see. So how does this relate to the "Cold Bug" tweak?

what level would you recommend RDXXX? I don't see why not to just run it on lvl8 (or whatever is the highest)

Misfit138 said:

I see. So how does this relate to the "Cold Bug" tweak?

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I think that when your cpu gets cold the memory controller drive strength increases, so if you lower the DRAM drive strength you can compensate for the high controller drive strength.

Janus67 said:

what level would you recommend RDXXX? I don't see why not to just run it on lvl8 (or whatever is the highest)

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Its also related to the type of chips on your RAM, Your VDIMM & Speed. TCCD/TCC5 is recommened the WEAK settings, and BH-5 etc is recommened NORMAL

Adrian Wong:
"Sometimes called driving strength. This feature allows you to control the memory data bus' signal strength. Increasing the drive strength of the memory bus can increase stability during overclocking. DRAM drive strength refers to the signal strength of the memory data line. A higher number means a stronger signal and is generally recommended for an overclocked module to improve stability. Supposedly TCCD works better with weak drive strength while just about everything else prefers a stronger signal."


BigToe
“If you leave the option at Auto this will set a weak drive strength, this is good for TCCD based modules but bad for anything else. From testing and debugging the board I have concluded the following. Options 1 3 5 7 are all weak, as is Auto, setting. 1 is actually the weakest option with 7 being as close to the normal weak setting DFI will allow us. Options 2 4 6 8 are the Normal settings, with 8 being the highest strength setting. If you are using TCCD you may want to try 3 5 or 7 as the drive settings as they usually seem to allow the modules to clock well. If you are using VX, or the new BH Gold, or any other modules from the OCZ range you may want to try 8 or 6.”





!! Has a Large Influence on Stability !!

in fact you may want to read all of this to get a good idea on Memory settings.


brought to you by the good guys over at dfi-street
http://www.dfi-street.com/forum/showpost.php?p=203179&postcount=4

Xtreme Barton said:

in fact you may want to read all of this to get a good idea on Memory settings.


brought to you by the good guys over at dfi-street
http://www.dfi-street.com/forum/showpost.php?p=203179&postcount=4

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Yes, I'm registered at DFI-st as well; very helpful forums there also.
Thanks for all the replies.

Interesting, so if I am to understand this correctly, 7 would be the strongest of the WEAK settings, followed immediately by 2,4,6, and finally 8 being the highest.

I'll have to keep this in mind, because like every DFI owner, the tweaking never ends..........

1 3 5 7 are all weak
2 4 6 8 are the Normal settings

so yes 8 is the strongets of all the settings

Janus67 said:

what level would you recommend RDXXX? I don't see why not to just run it on lvl8 (or whatever is the highest)

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LVL8 is the highest that you can go and that would be recommended for your Redlines since they strive on high Vdimm.

I ran my early TCC5's on LVL8 the highest with 3.2V on the Vdimm.

well mine is bh-5/utt but what level of the drive strength.

Janus67 said:

well mine is bh-5/utt but what level of the drive strength.

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Your RAM is not BH5, its UTT-CH5 and as I said before you should run it at 8 if your Vdimm is higher then 3.3V.

RedDragonXXX said:

Your RAM is not BH5, its UTT-CH5 and as I said before you should run it at 8 if your Vdimm is higher then 3.3V.

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Let me add a side note, I've been using only WEAK Drive strenght (7/1 or (7/2) for my Redlines. Everytime I used the Normal Drive strenght I can't get the system booting if memory frequency is higher than ~255MHz.