Is 850w PSU OK for sli 780?

sgoaty

sgoaty

sgoaty

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I have a 3770k @4.6ghz with 1.3v and 2 x GTX780 one reference and one classified. I know both cards work perfectly alone as i have gamed with them individually without issue.

I did try to overclock the cards in sli but as soon as I messed with anything in evga precision it wouldnt complete 3D mark and i was unable to until I uninstalled precision.

I put this down to a software issue but ive had a couple of random restarts and tonight I had a BSOD after about 40 mins of BF3.

I just wonder if my PSU might be borderline for the second card?


Its an XFX Pro Core edition 850W

Thanks
Scott
 
Your PSU should be fine. It's a Seasonic underneath, so you know it's a quality unit.
 
Psu should be fine, can you remember what the bsod error code was? It could be down to something else in your system.
 
If heavily overvolting and overclocking the cards, the psu may indeed struggle. But on stock voltage overclocks it should be ok.
 
I overclock mine on a 760w without any problems, 850w is more than enough. As Setter pointed out tho ^ I don't mess with voltages, that could be a different story.
 
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This is the only BSOD Ive had but there has been a couple of lock ups and restarts with DXgkrnl.sys driver.

The OC on my CPU and ram is prime stable and I have no issues running only one card. I did try re installing the Nvidia drivers too.

Thanks
Scott
 
Thanks for the input Kaku but as ive said my overclock is perfectly stable with prime and the whole system is stable with only one card installed.
 
kaku said:
Try bumping vcore up a notch. That's what 0x124 usually is.
Click to expand...

Worth a shot?

Just because its prime stable doesn't mean that some other program/ windows process might not cause it to BSOD if it's borderline. Might be that with the extra draw of the second card on motherboard and PSU you're getting slight vcore droop.
 
Its funny you should ay that because I originally had it prime stable for about 18hrs but it would crash out of BF3 within about 5 minutes so I bumped up the V core til that stopped happening then added a bit on i think it was .02v.

But surely if my PSU is within spec and not overloaded I shouldnt have to add more voltage to compenate for a higher load?
 
As you just said, it was prime stable and crashed on BF3, prime stable is more for testing temps than anything.
As said, try adding Vcore and see if it cures it, if not you can always put it back down.
 
We are kind of going round in circles here.

I got the CPU stable in prime and BF3 and i added a bit of V core on top of that already Ive spent countless hours playing this way with both my single 780 and with dual 7970s.

Now to suggest me adding another 780 in to the mix means my CPU all of a sudden needs even more V core does not make sense to me at all.
 
So I must be totally nuts for planning 780 SLI with a heavily OC'd 2600K on my 750W XFX Pro 80+ Silver at some point then?

I was under the impression that even that would be fine? :p

PSU calcs recommend 775W for 100% TDP and 100% peak load including overclocks, and they are always over-cautious.
 
I just read my last post back and it came across quite abrupt it wasn't meant to sorry.

The point i was trying to make was if its not a power issue why would i need to ad more v core to compensate? Just looking for a bit of explanation please.
Thanks
Scott
 
sgoaty said:
We are kind of going round in circles here.

I got the CPU stable in prime and BF3 and i added a bit of V core on top of that already Ive spent countless hours playing this way with both my single 780 and with dual 7970s.

Now to suggest me adding another 780 in to the mix means my CPU all of a sudden needs even more V core does not make sense to me at all.
Click to expand...

Makes perfect sense. The 780s are more powerful cards saturating the pcie lines which are direct to cpu not via a northbridge, effectively by adding a second card you're adding extra load to the cpu requiring more voltage to be stable.
 
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