7770 on old psu? (365w)

[LucoTF]

Hi

Would my stock psu be able to run a 7770? Not forever, just till about xmas or so...

365w HP, 12v rails are as follows:
12v @ 12a
12vcpu @ 14.5a

The problem is this psu doesn't have a 6pin. It only has a single 4 pin too, so I'd be using a single 4pin to 6pin adapter.

Thoughts?

 

[dannylivesforher]

It seems your PSU is not good enough to handle a 7770. For a 7770 atleast a 500W PSU is recommended,though wouldn't be a problem if your PSU is efficient enough to deliver atleast a 300W. But the problem seems to be with your 12V rail. For the 7770,at least a current of 20A is needed on the 12V rail. To be more precise,19.25V. Seeing that your PSU has only 12A on the 12V rail,I'd say you shouldn't waste your money buying the 7770. Instead,you could get a new PSU first and then get the card,or you could go for a lower series GPU and get a decent PSU which can deliver enough power.
I'd suggest you should get a 7750 instead of the 7770 and with the money spared,you could get a 450W PSU from a good brand like Corsair or a 400W from Seasonic,whichever you find appealing. Or as an alternative,you could take a look at the GTX 650,along with a good PSU instead of the 7770.

 

[LucoTF]

Where does the 20a figure come from?

Correct me if I'm wrong, but the max draw of the 7770 is 80w, so on a 12v rail that's under 7 amps.

 

[dannylivesforher]

Actually,what I said was about the current on 12V rail required for the 7770. Not the power consumption of the card in Watts. You can see that I'm right...Here:
http://forum-en.msi.com/faq/article/printer/power-requirements-for-graphics-cards

 

[coozie7]

I think the 7770 can draw a bit more than that but even so, a 16x PCI-E slot can provide 75 Watts directly to the card through its electrical connections, the extra 6 pin PCI-E connector isn't likely to put too much of an additional strain on the PSU.
If this was a stronger card I'd say a better PSU would be a good idea but you'll be fine as long as the system isn't running with a heavy overclock and has several HDDs and many fans.

 

[LucoTF]

But Amps = watts / volts

20amps is 240 watts (on 12v rails)

Thanks for that link - it states that the total load on the system is 231w at full load with a 7770 during tests and about 86w max draw for the 7770 itself.

 

[dannylivesforher]

But Amps = watts / volts

20amps is 240 watts (on 12v rails)

Oh...I'm sorry I was unaware of that. Thanks for the new information...

 

[LucoTF]

UPDATE

My 7770 arrived yesterday! I connected it last night using a single 4pin to single 6 pin and it booted to the desktop no problem. Didn't have time to try it with any games.

BUTTTTTT

I'm paranoid. I've heard bad things about them molex adapters and my PSU is quite old. So I went and ordered a cheap PSU with 34a on the 12v rail and two 6/8 pin connectors (a corsair) so I can game without worry

 

[coozie7]

Don't berate yourself for being cautious.
And Corsair are one of the better makers with a solid reputation, all in all I think you've made some sensible decisions.
Enjoy and relax!

 

[LucoTF]

Thanks coozie and thanks for your advice!

 

[dannylivesforher]

Yeah,just like coozie said,you've made a good decision buying that corsair PSU. Now do some serious gaming without worrying....

 

[LucoTF]

Yeah,just like coozie said,you've made a good decision buying that corsair PSU. Now do some serious gaming without worrying....

Thanks, I will!