ATI 3850/3870 Voltmod thread

[Greg_1]

i think :
do you have the HD3850 bios Fixed or original bios ???

regards

I got the newest bios for my card, and it's fine. Now I can get even 890 but it's unstable
max stable for 1.45V I got 880MHz

btw. is the score 19k for 3850 512mb 880/1080 and E6300@3.2GHz on Vista 32-bit and 7.11 cat is ok ?

[RealyPssd]

So you pencil the yellow part in the NEW pictures and not the blue part circled in the OLD pictures that were posted here?

[Rumon]

Just Tested the new Pencil Mod and it works great its easier to apply
Here is a image for anyone that is confused about the Pencil mods



The Mod is exactly the same for the 3850 the only difference is the
Resistance measuring point. Its the Right Blue Square and the Screw Above 'Q1252/Q1612/Q1602'
Top left Corner of the image

[jimmyz]

Ok, I'm new to the DMM. Which dot is the ground?

best ground is the pins on the power plug. i push the dmm in one of the ground holes and it holds it for me. BTW the ground ones are the farthest from the board. the ones closest to the board are positive.

[sniper007]

I have a 3850. Whats the benefit if this volt mod if Im using stock cooler? = None?

[jimmyz]

I have a 3850. Whats the benefit if this volt mod if Im using stock cooler? = None?

I used mine on stock cooler with rivatuner adjusting fan speeds and it went to 850 on 1.4 v which maxxed the temps at 69c with fan at 60 %. crysis for about an hour.

[RealyPssd]

Thanks for that pic Rumon.

[Greg_1]

What Vcore is quite safe for 3850 ? now I have ~1.45V but I want more

[Norway]

Just Tested the new Pencil Mod and it works great its easier to apply
Here is a image for anyone that is confused about the Pencil mods



The Mod is exactly the same for the 3850 the only difference is the
Resistance measuring point. Its the Right Blue Square and the Screw Above 'Q1252/Q1612/Q1602'
Top left Corner of the image

In that one you pencil the same spot as i did to ground and it didn't work for me ...

[pdiggs]

In that one you pencil the same spot as i did to ground and it didn't work for me ...

I don't get it -- I can't get a pencil mod to work on my 3850. My analog multimeter is a little unreliable, but that still shouldn't stop a voltage increase. So, according to this mod, I'm supposed to be able to draw a tiny line of graphite across those two points and get a resistance decrease enough to dramatically increase voltage?? I don't really see how -- I've never done a pencil mod, but it doesn't seem a number 2 pencil is doing much when I'm attempting to put down some graphite on such a tiny spot.

Maybe someone can enlighten me with specific details of application technique of the actual mod as oppose to just showing pictures of the location. How do you apply the pencil, did you shave the tip to be a tiny flat point or did you leave it like a standard pencil??

Thanks.

And where the heck is the new Atitool, it would be nice to have new voltage control and monitoring..

[os008]

pdiggs, not a tiny line, keep grinding on that resistor with a 2B, or just move the pencil a bit with a 4B, you should get good results.

I tried it with a 2B, but had to keep grinding a lot just to get to 1.4v, and if you grind too much and find a lot of small particles everywhere, you have to blow it away to get constant voltage, or it will fluctuate.

[Mastericy]

+1 Vote for a reading voltages & resistance(especially resistance) How-To on these cards. Basics. I have to send my card back...its now apparently fryed.

[Rol-Co]

Example of the mod



and some results.





2005 need more cpu power to get a decent score

[Onecar]

Couldn't you please try to test Crysis with/without the overclock? I'd like to know if it boosts Crysis's performance .

P.S.: Great clock, good job .

[gurusan]

For some reason I usually measure about .2V difference between the 2 marked vGPU points.

For example I measure 1.6v at the Black point and 1.41 at the green point.

Which is the real vGPU? At stock without any mods the black point says 1.45v (!!!) and the green one says 1.27v

BTW I have a Powercolor 3850pro 512mb

[jimmyz]

I would say the black would be closer to the truth. could you get a little further back so we could see more of the card, there may be a better place to check.

[gurusan]

but 1.45v stock? also when it's at stock I have a 780mhz limit on my clock....that would be terrible for 1.45v

and ok I'll have upload a better pic in a bit....doing some 3dmark runs

[gurusan]

[h3x0r_1984]

What would be the safe temperature on the Voltage regulators on the 3850 ?? I changed the stock cooling ,put some decent radiators there ,and in FUR i got about 60-65 degrees on that spot(finger-measured ).Is it ok?

[jimmyz]

[IMG][/IMG]



let us know what the readings are. one or all of the points should be a read point.

[Greg_1]

scores 20020 in 2005 and 12216 in 2006 3DMarks on 3850 512mb@877/1090 and E6300@3400 are ok ?
Cat 7.11 WinXP SP2

[gurusan]

Thanks so much jimmyz!

I currently have it pencil-modded so it won't show 1.27v...but it was as I suspected.

The black point I was measuring first is the incorrect vGPU and displays a few 10ths of a volt higher than the actual vGPU. The green circled point and almost all of the other points you showed me display my vGPU.

1.54v idle and 1.57v full load. Have it 100% stable @ 958.5core/1098mem

Temps are around 39-40c load under water with a MCW60A.

thanks again!






Now, has anyone figured out a vGDDR mod? This mem already does 1098 which is great, but it would be even better if I could just squeeze a bit more out of it...something like 1150-1200

[Mastericy]

I was trying to read resistance from the 'measurement point' next to the new pencil mod...machine restarted and I have blue lines. Beautiful. RMA time, huh?

[HousERaT]

RMA a card you fried on your own because you don't know what you're doing? Real classy.........

[jimmyz]

When you decide to mod a card you assume responsibility. you killed the card, now be mature about it.


never measure resistance with power to the card.