Test results: Flashing BIOS to lower 2D clocks for lower noise, heat, and amp draw - Overclock.net

KinZee · 07-04-09

IF NEED ARISES, I CAN MAKE A TUTORIAL ON BIOS MODDING & FLASHING 4800 SERIES CARDS

So, as I had posted a few days ago, my newly acquired 4870's were idling at pretty high temps. 65C @ 55-60% fan or so. I knew there had to be something up... After diggin around for a bit, I found a few threads on downclocking the 2D clocks even further than what ATi had done already with their "PowerPlay" technology. OEM 2D clocks only dropped the core clock from 750-600. GDDR5 remains at 900mhz.

After grabbing the few necessary apps, I was on my way tweaking the 2D/3D clocks and voltages as well as the fan speed IC in the GPU BIOS to accommodate my personal style.

The applications I used were: ATIFlash, Radeon BIOS Editor, and GPU-Z.

ATIFlash : http://www.techpowerup.com/downloads...lash_3.60.html
GPUZ : http://www.techpowerup.com/downloads...-Z_v0.3.4.html
RBE : http://www.techpowerup.com/downloads...tor_v1.21.html

After about an hour and a half of fiddling and writing flashes to the cards, I was finally happy with the results...

Dropped 2D voltage from 1.26 --> 1.10v
Dropped core clock speed from 750mhz to 200 mhz
Dropped GDDR5 clock from 900mhz to 250mhz.

End result and testing methodology:

Amp draw before tweaks: 28.5A
Amp draw after tweaks 6.8A
Approx wattage saved @ idle = 75watts

Idle Temps before tweaks : 65C @ 55-60% fan
Idle Temps after tweaks : 44C @ 44% fan
Also dropped CPU idle temps back to my normal 34C from 38C prior to flash. This is not doubt due to less ambient heat warming my CPU HSF.

Still plays 1080p videos just fine @ 2D clocks and act just like normal. I am 100% happy with the outcome on this endeavor, and would DEFINITELY recommend this to anyone looking to drop their idle temps dramatically on a 4870.

skugpezz · 07-04-09

nice going, now lets see some nice overclocking, you got some nice underclocking

KinZee · 07-04-09

Quote:

Originally Posted by skugpezz

nice going, now lets see some nice overclocking, you got some nice underclocking

Currently sitting on 860/1090 FurMark stable @ 100% fan. For benching.

24/7 OC is 800/1000 on auto fan.

Stampede10343 · 07-06-09

I did this before it works ok i lost like 3 degrees, but my card has a dual slot cooler and sits at around mid 30s idle, and i've only been able to get it to like 56 on furmark, even with some overclocking, but no matter how high i set the voltage(safely) i cant get over 700/1000 on my 4850.. oh well. I'll experiment more when i get my new card.

KinZee · 07-06-09

100 views and 2 replies...

Stampede10343 · 07-08-09

idk what it was, i'm thinking incompatability with windows 7, but i almost bricked my card, my flash setting freezed when finished. When i rebooted it didn't display. I've gotten it to work fine before just not on 7.

SyncMaster753 · 07-08-09

I like the idea, i'll definately try this. My summer CPU idles are mega high.

but not as extreme as 200/250/1.10, i have aero on after all (don't know if that needs 3d clocks though)

KinZee · 07-08-09

Quote:

Originally Posted by SyncMaster753

I like the idea, i'll definately try this. My summer CPU idles are mega high.

but not as extreme as 200/250/1.10, i have aero on after all (don't know if that needs 3d clocks though)

200/250 is fine for me... Win7 Aero and 1080p playback just fine.

The card still has 800sp you know...

Quote:

Originally Posted by Stampede10343

idk what it was, i'm thinking incompatability with windows 7, but i almost bricked my card, my flash setting freezed when finished. When i rebooted it didn't display. I've gotten it to work fine before just not on 7.

I do all of my flashing from a bootable DOS flash drive. had too many bad experiences w/ OS flashing.

LaoFX · 07-08-09

Thanks for this! Rep+

hellr4isEr · 07-09-09

cool.. but this underclocks the 2d portion.. how about when it needs to go full speed 3d.. does it switch over to normal clocks for 3d? or is that underclocked as well?

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Test results: Flashing BIOS to lower 2D clocks for lower noise, heat, and amp draw

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