7870 tahiti le power consumption

[sepultribe]

Greetings, i've just bought a used vtx3d 7870 black edition and i have some questions regarding the power draw of the card. The system this card is going to consists of a g3430 pentium (53w), a h67 mATX m/b, 2x 2gb 1333mhz ddr3 ram, hdd+dvd, the regular stuff. The psu is a deer 400w, not very good i know but the rest of the system is low power. Now it says that is has 2 rails for 12v with 13A & 14A each so 27A combined. That is 300watts. I have read in various forums that the tahiti le needs around 30-35A and this seems somewhat beyond what I think it should need, given that it is a 200w tdp card based on reviews i have seen online. What i plan to do is put it on -20% power control from the catalyst center and maybe lower the clocks and voltage a bit, in order to bring the maximum power consumption to less than 150w if possible . What i want to ask is when the system powers on the clocks are on 2d mode and low watts correct? So it should let me install windows with no problems and boot fine until i tweak the power control? And after i lower max power,clocks,voltage will the two 12v rails be enough?

Personally i see them as enough theoretically as the 2 6-pin connectors are rated at 75watts each and that means around 6amps witch is more than half of the 13 and 14 of the psu theoreticall maximum.

Thank you for your time

 

[Law-II]

Hi

Welcome to TPU

What i want to ask is when the system powers on the clocks are on 2d mode and low watts correct?

No; state #0 - Boot VDDC 1256 3d

Example


Note: State 1 - performance #4 VDDC 950 2d

atb

Law-II

 

[sepultribe]

hi there, so the card boots with stock 3d clocks and voltage? but since it only draws basic textmode and framebuffer stuff the load should be minimum right? so it should consume little power?

ps: can i edit the state 0 clocks and voltage with vbe7? will that affect the performance clock and voltage range afterwards?

thanks

 

[Law-II]

Hi

hi there, so it draws full power on power on until it loads into windows?

As far as I am aware; in accordance with the vbios image when the vga card runs it's self test at boot

Note: other members of the TPU community may be able to add clarity to this or confirm otherwise

ps: can i edit the state 0 clocks and voltage with vbe7? will that affect the performance clock and voltage range afterwards?

Not with VBE7; may be able to get a member of the TPU community to HEX Edit the voltage
[however; there is a chance the vga card will not boot as intended]

Note: ask sentye for assistance in this thread here [may be able to assist]

atb

Law-II