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TH7II vrambus mod?

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nautikah

New Member
Joined
Feb 24, 2002
can anyone tell me what is the purpose of the vrambus mod and if it is worth doing? If so can someone post link how to. thanks:)
 

Redphex

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Apr 21, 2001
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lost
it's a known fact, that higher operating voltages will get you cleaner signal-flanks, which is a GOOD thing when you're running PC parts beyond specs - no matter if CPU or RAM.
More voltage increases the need for better cooling, thouhg.

a VRambus Mod on the TH7-II would look something like this
http://overclockage.50megs.com/cgi-bin/i/th7iiramvoltmod.jpg
and should be quite easily done.

dunno if anyone has already modded his board.
 

gone_fishin

BandSaw King
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Feb 11, 2002
Location
U.P. Michigan
I would be very carefull and only power up after testing resistance with a meter first. I've read of people frying stuff out because they turned the knob a hair too far. The reported sweet spot is 7k to 8kohms of resistance and don't go beyond 2.7volts. The safest way would be to use a series of small 1K resistors and one 1k pot at the end. If you can find a 5k or 6k resistor to start the chain off it would be even better.

I hope this made sense. I have studied up on it but haven't done it. Heat seems to be a problem for my modules and this would only make it worse.
 

MrNatural

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Mar 25, 2002
Location
Florida
Well I've done the mod and right now I have my vrimm voltage at 2.75v. I have my FSB running at 193/772 and my RDRAM running at 193/579/1158. Doing just fine right now. Be sure as mentioned to get your POT set to where there is resistance or you could find yourself with no memory. I'm using a 10K pot and when I powered up even with it set at the very bottom of the POT resistance it still booted with the vrimm voltage at 2.7v so I didn't have to bump it very much at all.
 
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Redphex

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yo ... decided to add the VRambus mod to my TH7
after some tries with a 10K Poti i set the Voltage to 2.7V
had it by mistake up to 3.6V without having my Rimms goin' up in smoke.

let's see if there's some stability improve in for me :)

//update:
hmmm. disappointing. even pumping the Vrimm up to 2.9v won't give any significant improvement. the stability-limit is still around 510MHz. :(
 
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jdmcnudgent

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Jan 11, 2002
Location
tOLEDO, OHIO, the heart of it all!
MrNatural said:
Well I've done the mod and right now I have my vrimm voltage at 2.75v. I have my FSB running at 193/772 and my RDRAM running at 193/579/1158. Doing just fine right now. Be sure as mentioned to get your POT set to where there is no resistance or you could find yourself with no memory. I'm using a 10K pot and when I powered up even with it set at the very bottom of the POT resistance it still booted with the vrimm voltage at 2.7v so I didn't have to bump it very much at all.
yes, but you have 1066 rambus, not 800, right?:D
 

MrNatural

Member
Joined
Mar 25, 2002
Location
Florida
Redphex said:
yo ... decided to add the VRambus mod to my TH7
after some tries with a 10K Poti i set the Voltage to 2.7V
had it by mistake up to 3.6V without having my Rimms goin' up in smoke.

let's see if there's some stability improve in for me :)

//update:
hmmm. disappointing. even pumping the Vrimm up to 2.9v won't give any significant improvement. the stability-limit is still around 510MHz. :(

That may not be the RDRAM but rather the DRCG chips.
 

Redphex

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i equipped these little buggers with heatsinks and they're getting a good blow from the 80x80 fan above the rimms. :(
 

Eggroll

Registered
Joined
Apr 5, 2002
Hello all. This is my first post so please gentle.

I hate to show my ignorance about matters regarding electronics to start out with, but I'm confused about something. Above, Mr. Natural says "Be sure as mentioned to get POT set to where there is no resistance or you could find yourself with no memory." Then in "Overclocking - AMD Motherboards - Get Your Volt Mods Here," Doctor says "On some mobo's, the 47K isn't enough resistance to disable the mod completely by raising it to the max, so PPL have been using 100K pots with good results." This thread continues with posts implying that "to the max" means a higher number than 47K like 60K or 100K or whatever.

I can't reconcile these two statements because to my electronics/physics blocked brain they appear to be saying the opposite things - one, that you start with no resistance and slowly increase it to raise the voltage and, the other, that a high resistance disables the mod and you work your way to the mod by slowly lowering the resistance to increase the voltage.

I ask because I want to do this mod with the new setup I'm putting together and I don't want to fry my RDRAM. Any clarification would be greatly appreciated. I know this is something simple like that V=IR thing, but I'm telling you, I'm blocked.

Thanks,
Eggroll :eek:
 

MrNatural

Member
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Mar 25, 2002
Location
Florida
Eggroll said:
Hello all. This is my first post so please gentle.

I hate to show my ignorance about matters regarding electronics to start out with, but I'm confused about something. Above, Mr. Natural says "Be sure as mentioned to get POT set to where there is no resistance or you could find yourself with no memory." Then in "Overclocking - AMD Motherboards - Get Your Volt Mods Here," Doctor says "On some mobo's, the 47K isn't enough resistance to disable the mod completely by raising it to the max, so PPL have been using 100K pots with good results." This thread continues with posts implying that "to the max" means a higher number than 47K like 60K or 100K or whatever.

I can't reconcile these two statements because to my electronics/physics blocked brain they appear to be saying the opposite things - one, that you start with no resistance and slowly increase it to raise the voltage and, the other, that a high resistance disables the mod and you work your way to the mod by slowly lowering the resistance to increase the voltage.

I ask because I want to do this mod with the new setup I'm putting together and I don't want to fry my RDRAM. Any clarification would be greatly appreciated. I know this is something simple like that V=IR thing, but I'm telling you, I'm blocked.

Thanks,
Eggroll :eek:

Well what i said was a little confusing is true. Why I put the NO in I'm not sure. I'll remove it but there should be resistance across the POT to make sure that the voltage to ground is not at it's max.
 

Eggroll

Registered
Joined
Apr 5, 2002
Thanks, Mr. Natural. That helps. I'm just trying to figure this stuff out one question at a time.

Eggroll.
 

Redphex

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Apr 21, 2001
Location
lost
for all those who think about solderin' around

some real-life results:

Pot to 0 resistance:
System hangs with Postcode 01
Pot to ~0.6-1kOhm
System will boot - Vrimm @ 3.6V

the more Ohms the Pot is se to, the less the Vrimm is increased.
I'd say setting it to 7-8kOhm would give a nice Vrimm to boot up and check things out without the need to panic.
 

jdmcnudgent

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Location
tOLEDO, OHIO, the heart of it all!
thanks buddie, am going to do it right now. now, by increasing the vrambus voltage, am i going to need to have a fan on the rimms to run at 150 fsb, and will i still need the diffenential at 6x with the mod? also, i was thinking of taking off the covers and removing the heat tape under the cover. will this make these run cooler, even without heatsinks on them and just a fan? or should i just leave them on and use the fan? thanks mr natural.:D
 

MrNatural

Member
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Mar 25, 2002
Location
Florida
jdmcnudgent said:
thanks buddie, am going to do it right now. now, by increasing the vrambus voltage, am i going to need to have a fan on the rimms to run at 150 fsb, and will i still need the diffenential at 6x with the mod? also, i was thinking of taking off the covers and removing the heat tape under the cover. will this make these run cooler, even without heatsinks on them and just a fan? or should i just leave them on and use the fan? thanks mr natural.:D

Remeber that the DRCGs may still hold you back on the reaxhing of 150/600 because the 03s are only rater at 100/400mhz so to see a 50% increase in numbers will be realy hard. I've pushed the vrambus voltage upto 3v and saw no help in hitting and mauntaining 600/1200 speeds even with PC1066 RDRAM.
 

jdmcnudgent

Member
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Jan 11, 2002
Location
tOLEDO, OHIO, the heart of it all!
ok, did mod, very nicely done too. now problem is i hang at 26 every time i try to boot. had the rambus set at 300, diff at 6x, vrambus at 2.72, and i tried the fix option, and the divider option, with no luck. what should i do? i couldnt even boot to 2300. i need some help. thanks.:D
 

MrNatural

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Mar 25, 2002
Location
Florida
jdmcnudgent said:
ok, did mod, very nicely done too. now problem is i hang at 26 every time i try to boot. had the rambus set at 300, diff at 6x, vrambus at 2.72, and i tried the fix option, and the divider option, with no luck. what should i do? i couldnt even boot to 2300. i need some help. thanks.:D

Turn the pot for the vramgus down to where it is making no voltage adjustment. Then boot. After you go into the bios then liik at the system health area and while looking at the vrambus voltage, slowly increase the voltage. I leave mine at 2.7 and does just fine. Make sure also to have Spread Spectrum Enable. This cleans up the data signal for the rambus, Also put some good cooling on the memory and the DRCGs. I have a 5000rpm fan sitting ove my sticks and DRCGs. Helps allot.
 

jdmcnudgent

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Jan 11, 2002
Location
tOLEDO, OHIO, the heart of it all!
slowly but sure buddie, im at 2609 right now and steady moving up. mem is at 780 right now, and i know that it will at least do 920.:Dwell, i cannot run 3dm2k1se at this speed. it craps out, and starts back up fine, but it is saying that my video card has caused the problem. what should i do?
 
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MrNatural

Member
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Mar 25, 2002
Location
Florida
jdmcnudgent said:
slowly but sure buddie, im at 2609 right now and steady moving up. mem is at 780 right now, and i know that it will at least do 920.:Dwell, i cannot run 3dm2k1se at this speed. it craps out, and starts back up fine, but it is saying that my video card has caused the problem. what should i do?

What have you got the AGP/PCI set to int he bios? Fixed?