ATI 4850/4870 voltmod thread

[mth91]

I just did the pencil mod up to 1.34v last night. I have a duorb and heatsinks on everything, but i'm getting hellish temps.



Anybody have any input?

That's under load in atitool.

http://www.overclock.net/graphics-ca...ml#post4269368

Refer to that for more information.

By the way, i'm using a duorb with zalman rhs1's applied to the vram with thermal tape, and as for all the stuff on the right. I have the bigger rhs1's applied using arctic silver adhesive. I applied the adhesive this morning, so it may be that it just hasn't set yet, but those temperatures at 1.34v are still ridiculous. They should be lower. My vram temps when up a lot too for some reason even though I didn't voltmod the ram. I'm stumped.

[rangerone7669]

what would the approx. core voltage be if i used a 33ohm resistor? i saw one member used 3 10ohm resistors for 1.36 core volt.

i'm using a hr03-gt so i should be ok on temps. i just cant find any 50 or 100 ohm pots in stock at any ;ocal radio shacks.

[stangracin2]

I just did the pencil mod up to 1.34v last night. I have a duorb and heatsinks on everything, but i'm getting hellish temps.



Anybody have any input?

That's under load in atitool.

http://www.overclock.net/graphics-ca...ml#post4269368

Refer to that for more information.

By the way, i'm using a duorb with zalman rhs1's applied to the vram with thermal tape, and as for all the stuff on the right. I have the bigger rhs1's applied using arctic silver adhesive. I applied the adhesive this morning, so it may be that it just hasn't set yet, but those temperatures at 1.34v are still ridiculous. They should be lower. My vram temps when up a lot too for some reason even though I didn't voltmod the ram. I'm stumped.

bump that fan speed up

[LuxZg]

@sandwichamwin - I've seen this picture on your blog. Nice idea! Have you tried it on 4870 as well? Any results if it would cool better this way+120mm fan, or in stock setup with whole cooler?

[mth91]

You can't bump the fan speed up on a duorb. That's just the percent that the stock cooler would be running at if I had it on.

[mth91]

Does anybody have any idea what GPU temp #3 is?

[stangracin2]

i'd be more worried about number 2

[mth91]

Don't worry, I am. I'm having serious issues with the temperatures on here though. I don't know why, it's really odd. Even at 1.32v the #2 will get on up there to 95c. I put on arctic silver adhesive this morning, and by now it's surely set. I'm considering reseating the duorb. Is there a specific way that you should put the as5 on, because there's always a chance that I didnt do it right.

[sandwichamwin]

A lot of people on other forums are having trouble with the Duoorb cooling the 4870 even at stock speeds. Under load they're getting temps well up to and beyond 90 degrees which is worse than stock.

I'd get some water on that thing, these suckers get hot, even more so after extra volts and overclocking. I'm sure a TRUE would do the job aswell


@LuxZg i never tried it on the 4870. I doubt it would be better than the stock fan due to the way the heatsink is designed. If you look closely, the fins are 'closed' at the top so the air needs to be forced from the side to be effective.

[LuxZg]

@LuxZg i never tried it on the 4870. I doubt it would be better than the stock fan due to the way the heatsink is designed. If you look closely, the fins are 'closed' at the top so the air needs to be forced from the side to be effective.

Oh :/ Didn't know that. Well, there goes that plan Tnx for the info

[dejanh]

I tried to do the pencil mod on my VMEM on the 4870 but one of the resistors simply will not pencil in...any tips on what I can do? The first one dropped from 220ohm to 143ohm after pencil mod, but the second no matter how much I pencil stays at 220ohm.

Also, I tried and confirmed that a BIOS vmod on the 4870 does not work. This also includes the XOC BE version of the 4870.

Currently running my 4870 XOC BE at 870/1200 on stock volts in Vista Noticed however that C2D combined with this card gives about 20% - 25% better performance over my 5000+ BE X2 @ 3.2GHz. Kind of an ouch :s

[binormalkilla]

Ok I finally got around to measuring voltage with a multimeter, and I found that I idle at 1.05V (maybe 1.046, only 3 sig figs for my DMM) and load at 1.17.....WTF. I flashed the BIOS to 1.3V (I know 1.21V is the max, just wanted to be sure)
Any ideas why it's not going to 1.2V? Do some cards just not want to put out 1.2V without a hard mod? I Sapphire cards BTW.....flashed with the MSI BIOS, which I then edited to higher clocks.

[STaRGaZeR]

Also, I tried and confirmed that a BIOS vmod on the 4870 does not work. This also includes the XOC BE version of the 4870.

Have you tried to lower idle voltage too? It seems 1.263v can't be changed

[Zucker2k]

Could someone who did the hardmod (using 100k) for the VDDC post what resistance they're getting for 1.40v+? Thanks.

[Barr3l Rid3r]

Does anybody have any idea what GPU temp #3 is?

and what about #2 also?

[binormalkilla]

and what about #2 also?

I'm not really sure....I think there may actually be 3 diodes in the GPU.......at least that's what an Everest developer suggested.
I'm hoping for full Everest support soon so I can export all the values to my G15 (currently only GPU diode is supported)

[r4st4m4n]

Ok I finally got around to measuring voltage with a multimeter, and I found that I idle at 1.05V (maybe 1.046, only 3 sig figs for my DMM) and load at 1.17.....WTF. I flashed the BIOS to 1.3V (I know 1.21V is the max, just wanted to be sure)
Any ideas why it's not going to 1.2V? Do some cards just not want to put out 1.2V without a hard mod? I Sapphire cards BTW.....flashed with the MSI BIOS, which I then edited to higher clocks.

If you want you to get 1.2V, you have to write 1.2V in the BIOS.

When you write 1.3V, the bios will consider it as unknown/incorrect value and use the default value (1.05V).

[Viilutaja]

I have Sapphire HD4850 card. Why is it needed to flash it with other Manufacturers cards bios? Like some here do? Isn't Sapphire's bios good for OC?
Maybe i don't need to flash it after all, how can i make sure that the powerplay is working like it should? I don't have any wattage reading hardware.

[biohead]

Don't worry, I am. I'm having serious issues with the temperatures on here though. I don't know why, it's really odd. Even at 1.32v the #2 will get on up there to 95c. I put on arctic silver adhesive this morning, and by now it's surely set. I'm considering reseating the duorb. Is there a specific way that you should put the as5 on, because there's always a chance that I didnt do it right.

Are you sure you meant Arctic Silver Adhesive ??

[sandwichamwin]

Eeep, i hope for his sake that's a typo!



I finished modding the second 4870. Went straight to 900/1050 1.4v... no worries

Here's some more modding :banana::banana::banana::banana:. I do have a plan for sinking the rest of the card... . And btw, using 600v cloth covered wire is not ideal for such small work!

[aussie-revhead]

Can you clock them that high with CF enabled ? Did you flash them ?

[babalouj]

Also, I tried and confirmed that a BIOS vmod on the 4870 does not work. This also includes the XOC BE version of the 4870.

Do you have the XOC BE bios? If so, can you please post it?

[sandwichamwin]

Can you clock them that high with CF enabled ? Did you flash them ?

They maxed out at 940mhz 1.4v. Like before, more voltage doesn't seem to get me anywhere. I'll see what the newer 4870 can do alone, it might be one dud card holding back.

[STaRGaZeR]

Holy **** man, what about those voltage regulators

[sandwichamwin]

Holy **** man, what about those voltage regulators

It's a job for the w/e. I can't get any sinks to stick... so i might chop the stock hsf in half and bolt it on.