Does GPU overclock with no voltage bump increase watt usage?

[Eureka]

In terms of power from the PSU, yeah. True limiting factors would be heat and the chips themselves.

On the other hand, why crossfire two 7770s? Surely a single 7870 would be better and cheaper.

 

[frozentundra123456]

So, a lot of OC headroom for both GFX cards and maybe CPU if needed?

Yes, but if you dont have one or both of the 7770s now, you might want to consider a single more powerful card than using crossfire 7770s. Maybe a 660TI, HD7850/7870 or something like that. I think in general it is better to get a single more powerful card than to crossfire 2 rather weaker cards.

Edit: Sorry Eurika, didnt see you post. It must have come up while I was composing mine. Anyway, I agree with you.

 

[Pedroc1999]

A single HD7770 suits my needs, i would like to avoid the 6850 because of the 40nm die that needs a diesel generator to keep it working (jks) I want my build to be upgrade able in the future, hence having a good PSU is essential to keep a future Crossfire importunity available. When i need more power i will get another 7770 and that will keep me more than happy, and if i need more processor i can always upgrade to steamroller and excavator. Even though dual 7770s will use more power than a 6850, it is more worth it tbh. I also want to experiment with crossfire so i have some future knowledge on the topic

 

[Eureka]

A single HD7770 suits my needs, i would like to avoid the 6850 because of the 40nm die that needs a diesel generator to keep it working (jks) I want my build to be upgrade able in the future, hence having a good PSU is essential to keep a future Crossfire importunity available. When i need more power i will get another 7770 and that will keep me more than happy, and if i need more processor i can always upgrade to steamroller and excavator. Even though dual 7770s will use more power than a 6850, it is more worth it tbh. I also want to experiment with crossfire so i have some future knowledge on the topic

That's really the wrong way to go. If a single 7770 suits your needs, that's fine, but when you need more power, you should just sell the 7770 and get a better card at the time.

What happens when you crossfire the 7770 is that you double the processing power but you're still limited by vram and ram bus. For example, take a HD7870. It's virtually two 7770s worth of parts on the same die. But you have double the vram and a faster rambus. You can actually use up all of that speed, as opposed to the 7770 crossfire where you'll choke on the ram (which you will if you plan on using this any time in the near future).

In fact, you could probably get a 7950 used in two years for much less, or a 8850 or a 9770 or whatever's out then.

The right thing to do is probably to downsize your PSU a bit, a 430W would do you well. If you're fine with a low-end card now, chances are you'll be fine with running a low end card later as well. You should realize that a low end card in the future will perform as well as a mid-range to higher-range card now (which is what a 7770 CF would be), but with much less power draw and with newer technology.

 

[Pedroc1999]

Yes i agree, It really depends on when more than one what and how... But i still want enough PSU to power my needs for the future and i think this will cut it well!

 

[Eureka]

Well, the 550W is a good compromise.. not too expensive, not too limiting. You could easily do one top-end CPU and one top-end GPU on that power supply as long as it has enough cables for everything.

 

[Pedroc1999]

Thanks for all the help guys. I am liking the hd7770 msi oc edition