ATI 3850/3870 Voltmod thread

[ORVILLE]

Vmem mod is not really worth it. 3850's gain much more from GPU Mhz than Mem Mhz. That's why 3850's clocked at 775/2000 perform almost identically to 3870's clocked at 775/2400. Going from 900 to 1050 on my memory gives me just 1-2% fps increase.

My 8800GTS G92 works the other way. GPU increases make little difference because the memory bandwidth is the bottleneck.

[Clint]

that's just bios modifications that do nothing at all, I need an unlocked bios for Gigabyte 3870 w/ DDR3 and VGPU eighter, can u take a clear picture of the back of the card and post here?

Sure, it will arrive here next week

[GenTarkin]

I got my freaking HUGEASS AC S1 rev2 today ... all I can say is WOW...I got the turbo fans to go with it.

Under load my GPU maintains less than 55C in 3dmark 06 ~ I would say less than 60C in games.
I think its time to pencil in some more graphite on this puppy bring its voltage up from 1.38v LOL

I cant believe the temp difference of 40C from stock heatsink...just WOW!!!

[MonsterMash]

there was one, but i know that for me it only caused artifacts.... whether it actually works or not, i dunno, but i didn't leave mine on.

Can you show me a picture of how to make it?
Thanks!

[Random Murderer]

Can you show me a picture of how to make it?
Thanks!

[Barr3l Rid3r]

Ok I've found a solution for Gigabyte HD3870 512MB DDR3 Qimonda....
Original Ver 70 locked bios 1.22V

at 859/2100Mhz

Used a Sapphire 3850 512MB DDR3 Qimonda Bios
Ver 71 Unlocked Bios 1.22V ( http://www.techpowerup.com/vgabios/2...12.071108.html )

+ Editor to set 1.22V 2D and 1.32V 3D And now I got 1.38V in Multimeter
@895/2100Mhz

( http://www.computerbase.de/downloads...tor/?url=17592 )

[Random Murderer]

Ok I've found a solution for Gigabyte HD3870 512MB DDR3 Qimonda....
Original Ver 70 locked bios 1.22V

at 859/2100Mhz

Used a Sapphire 3850 512MB DDR3 Qimonda Bios
Ver 71 Unlocked Bios 1.22V ( http://www.techpowerup.com/vgabios/2...12.071108.html )

+ Editor to set 1.22V 2D and 1.32V 3D And now I got 1.38V in Multimeter
@895/2100Mhz

( http://www.computerbase.de/downloads...tor/?url=17592 )

so gigabyte is marketing 512 3850's as 3870's? for shame.

[Barr3l Rid3r]

so gigabyte is marketing 512 3850's as 3870's? for shame.

well not really, 3850 used to have one less phase and not all solid capacitors, this 3870 is very robust and follow gigabyte ultra durable reference but comes w/ DDR3 1.0ns, Gigabyte 3850 comes w/ hynix 1.4ns and less components on pcb.

[Toritechie]

I have seen a few people in this forum report their Vmodded cores around 1.5v and OC'd to 1000mhz on 3870's.

I'm installing water cooling this week, and will be doing the pencil mod to both my Asus 3870's.

Can anyone running the pencil mod to such a voltage and overclock give me an idea of their resistance readings for the resistor in question?

[Clint]

well not really, 3850 used to have one less phase and not all solid capacitors, this 3870 is very robust and follow gigabyte ultra durable reference but comes w/ DDR3 1.0ns, Gigabyte 3850 comes w/ hynix 1.4ns and less components on pcb.

From what I can tell there is same amount of components but on the 3850 there are three capacitors that is of lower capacity. I'm planning to replace those with the same spec'ed capacitors as the 3870 have.

Cost will be a couple of $.

[Barr3l Rid3r]

From what I can tell there is same amount of components but on the 3850 there are three capacitors that is of lower capacity. I'm planning to replace those with the same spec'ed capacitors as the 3870 have.

Cost will be a couple of $.

Can u hit 850Mhz in yours already? If not maybe I can help... but Gigabyte will be the only one that can provide a unlocked bios for your card since no other card use hynix 1.4ns...

[JamesBong420]

yahoooo just hit 1053mhz core on my 256meg msi 3850....
thanks to some caps and of coarse shaminos OCP mod!! now i just need to get these mosfets colder.




SINGLE CARD
13k 06
1053mhz/1053mhz 1.65v Gpu
e4500@3.82ghz.
such a cheap setup im more then happy!!!
http://service.futuremark.com/compare?3dm06=5245969

3dmark 05
21250
http://service.futuremark.com/compare?3dm05=4010657

[JaD]

Can anyone confirm this?

[Riska]

It works fine og the 2 cards i have done it to

[JaD]

Ok I can confirm it myself, but i had no gains on samsung ddr4 over default voltage (wich for me is 1.99v). Raising to 2.10v just made things worse, giving artifacts at previously stable clocks.

[Random Murderer]

Ok I can confirm it myself, but i had no gains on samsung ddr4 over default voltage (wich for me is 1.99v). Raising to 2.10v just made things worse, giving artifacts at previously stable clocks.

that's the same problem i had.

[lowtcell]

Is this only for 3870 or will this work on a 3850?

If the pencil mod doesn't work, I will be hard modding and have 2 questions

1 Are both pots, core and mem, 100k ohm or is the mem one different?

2 Do I need to flash Bios with whatever voltage I'm trying to run, or just leave where they are now?

[Random Murderer]

Is this only for 3870 or will this work on a 3850?

If the pencil mod doesn't work, I will be hard modding and have 2 questions

1 Are both pots, core and mem, 100k ohm or is the mem one different?

2 Do I need to flash Bios with whatever voltage I'm trying to run, or just leave where they are now?

1- you use a 500k for the mem and a 100k for the core.
2- you can use the stock bios, but you will hit a wall at 864 core. you need the pll fix bios.

[lowtcell]

1- you use a 500k for the mem and a 100k for the core.

OK, thanks, I missed that in the thread,

2- you can use the stock bios, but you will hit a wall at 864 core. you need the pll fix bios.

I'm running HIS IceQ3 Turbo bios, CCC goes up to 900mhz with that. Will I still need the fix?

[Random Murderer]

OK, thanks, I missed that in the thread,

I'm running HIS IceQ3 Turbo bios, CCC goes up to 900mhz with that. Will I still need the fix?

no, if it doesn't hard-lock at 864 then you have the pll fix.

[jimmyz]

Use gpu-z to determine your bios number if it is ver xxx.071.xxx.xxx.xxxxxx it is unlocked lower than that are the locked bios's

[ceemic]

So only way to use unlocked BIOS with my Gigabyte 3870 512MB DDR3 ver 70. is flash it with 3850's BIOS?

[Clint]

So only way to use unlocked BIOS with my Gigabyte 3870 512MB DDR3 ver 70. is flash it with 3850's BIOS?

It shouldn't matter if the ID is 3850 or 3870, performancewise I mean.

Could you help me and scribble down the name and values on a capacitor on your card for me?
I'm about to mod my Gigabyte HD 3850 and would like the specs on those particular components.

I've squared them in with red in this picture:


Thanks for the help and XS friendly attitude

[raibemunn]

Those ultra durable gigabyte 3850 and 3870 have the same layout, right?
Difference comes in with caps and memory, anything else?
Id like to try vgpu on my 3850, but since its my first vgpu id like to be extra sure.

[Random Murderer]

Those ultra durable gigabyte 3850 and 3870 have the same layout, right?
Difference comes in with caps and memory, anything else?
Id like to try vgpu on my 3850, but since its my first vgpu id like to be extra sure.

no, the gigabyte cards use non-reference pcb's.