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Topic: What PSU do you use with a 4 GPU rig? (Read 10982 times)

member
Activity: 121
Merit: 10
June 24, 2011, 09:27:00 AM
#31
So why couldn't you just use a 6 pin PSU to 6 pin PCIE cable directly,...

I don't know why you are not getting it.  Here's a picture.

I don't KNOW if "they" make a 5pin-molex to 6/8pin-PCIe power cable.  But if not, then one must use an adapter in conjunction with a 5pin-psu(molex) cable.


I've never seen those 5 pin peripheral sockets before. All the modular PSUs I've seen use 6 pin peripheral connectors that look just like 6 pin PCIE plugs.




Mine looks like that, all slots are identical. I suppose with a PSU like that, you could try to acquire more cables instead of using molex->6pin adapters. However, it's easier to use adapters than acquire more pci-e cables Smiley
sr. member
Activity: 322
Merit: 250
June 24, 2011, 06:54:48 AM
#30
Why not to use Y-slitter to split 6pin PCIe to 2*6pin PCIe?

As I stated in the OP, Y-splitters are not recommended by the video card manufacturers.  That, and I don't have any. Tongue
member
Activity: 62
Merit: 10
June 24, 2011, 04:46:56 AM
#29
Well, I guess the only difference is that you would need a 4pin-Molex-to-6/8pin-PCIe modular cable. Not sure if they make those.

I think they make molex-to-6/8pin adapters. You could use an adapter with a molex-to-molex cable.
This would be a perfect solution.
Why not to use Y-slitter to split 6pin PCIe to 2*6pin PCIe?
legendary
Activity: 826
Merit: 1004
June 24, 2011, 02:05:07 AM
#28
So why couldn't you just use a 6 pin PSU to 6 pin PCIE cable directly,...

I don't know why you are not getting it.  Here's a picture.

I don't KNOW if "they" make a 5pin-molex to 6/8pin-PCIe power cable.  But if not, then one must use an adapter in conjunction with a 5pin-psu(molex) cable.


I've never seen those 5 pin peripheral sockets before. All the modular PSUs I've seen use 6 pin peripheral connectors that look just like 6 pin PCIE plugs.
full member
Activity: 148
Merit: 100
June 24, 2011, 01:50:38 AM
#27
a 35 dollar PSU, 600 watts.  powering 2x 5830 and 2x 5770 for a total 1ghash.

How are you powering the four cards? The specs I read show only 2 x PCIe 6+2 cables.  You must be using adapters.

Yes the built in pcie cables power the 5830s (2 plugs each card), and I use 2-molex>1-6pin adapters that came with 5770s to power them.  the 5770s only need a single 6pin.  
donator
Activity: 2352
Merit: 1060
between a rock and a block!
June 24, 2011, 01:46:08 AM
#26
Canary, So you are using TWO rigs to get your 1ghash?

'Cause if you're not using adapters, and your PSU only has four cables (two 6pins, and two 6+2pins), then it can only support two physical cards (not counting on-board GPUs).

I think you are confusing me with gmannn...  and it would be very easy to power his setup... 5830's are clearly covered...

5770 only needs 1 6-pin.  it would be very easy to convert 4 pin molex to 6 pin.  The PSU gmannn is referring to is fully capable of his setup.

Also, cards typically include such molex converters etc...  Don't confuse this with Y-splitters...

Hope this helps.
sr. member
Activity: 322
Merit: 250
June 24, 2011, 01:28:12 AM
#25
Canary, So you are using TWO rigs to get your 1ghash?

'Cause if you're not using adapters, and your PSU only has four cables (two 6pins, and two 6+2pins), then it can only support two physical cards (not counting on-board GPUs).
donator
Activity: 2352
Merit: 1060
between a rock and a block!
June 24, 2011, 12:54:50 AM
#24
a 35 dollar PSU, 600 watts.  powering 2x 5830 and 2x 5770 for a total 1ghash.

How are you powering the four cards? The specs I read show only 2 x PCIe 6+2 cables.  You must be using adapters.

better details here:

2x6 and 2x(6+2) connectors
sr. member
Activity: 322
Merit: 250
June 24, 2011, 12:49:43 AM
#23
a 35 dollar PSU, 600 watts.  powering 2x 5830 and 2x 5770 for a total 1ghash.

How are you powering the four cards? The specs I read show only 2 x PCIe 6+2 cables.  You must be using adapters.
sr. member
Activity: 322
Merit: 250
June 24, 2011, 12:45:04 AM
#22
So why couldn't you just use a 6 pin PSU to 6 pin PCIE cable directly,...

I don't know why you are not getting it.  Here's a picture.

I don't KNOW if "they" make a 5pin-molex to 6/8pin-PCIe power cable.  But if not, then one must use an adapter in conjunction with a 5pin-psu(molex) cable.

full member
Activity: 148
Merit: 100
June 23, 2011, 10:54:34 PM
#21
http://www.amazon.com/Diablotek-600-Watt-Power-Supply-PSDA600/dp/B003UWNL2O

a 35 dollar PSU, 600 watts.  powering 2x 5830 and 2x 5770 for a total 1ghash.

Underclocked single core sempron, no hard drives.  running linuxcoin via usb stick and 3x fans to keep things below 70c.
legendary
Activity: 826
Merit: 1004
June 23, 2011, 09:54:04 PM
#20
Well, I guess the only difference is that you would need a 4pin-Molex-to-6/8pin-PCIe modular cable. Not sure if they make those.

I think they make molex-to-6/8pin adapters. You could use an adapter with a molex-to-molex cable.
This would be a perfect solution.

So why couldn't you just use a 6 pin PSU to 6 pin PCIE cable directly, instead of a using a 6 pin PSU to 4pin molex cable combined with a 2 molex to PCIE adaptor? That's what I don't get and it seems extremely odd to me. If you can use the molex adaptors, then you should just be able to replace the whole molex cable with a PCIE cable.
sr. member
Activity: 322
Merit: 250
June 23, 2011, 08:47:44 PM
#19
Well, I guess the only difference is that you would need a 4pin-Molex-to-6/8pin-PCIe modular cable. Not sure if they make those.

I think they make molex-to-6/8pin adapters. You could use an adapter with a molex-to-molex cable.
This would be a perfect solution.
legendary
Activity: 826
Merit: 1004
June 23, 2011, 08:04:30 PM
#18
If you've got a modular PSU and not enough PCIE cables, couldn't you just buy more cables?

No, not really.  When you buy a modular PSU, it comes with ALL cables it can handle. So, the X4 1200w, for example, supports 6 6/2-pin cables, and includes 6 6/2-pin cables.  (That's 3 video cards)

If you need 2 more, you will need a converter to/from a molex, apparently.

So, whats the difference between adding an extra molar cable and adding an extra 6-pin PCIE cable?
sr. member
Activity: 322
Merit: 250
June 23, 2011, 07:28:14 PM
#17
If you've got a modular PSU and not enough PCIE cables, couldn't you just buy more cables?

No, not really.  When you buy a modular PSU, it comes with ALL cables it can handle. So, the X4 1200w, for example, supports 6 6/2-pin cables, and includes 6 6/2-pin cables.  (That's 3 video cards)

If you need 2 more, you will need a converter to/from a molex, apparently.
legendary
Activity: 826
Merit: 1004
June 23, 2011, 01:48:26 PM
#16
If you've got a modular PSU and not enough PCIE cables, couldn't you just buy more cables?
newbie
Activity: 182
Merit: 0
June 23, 2011, 07:26:45 AM
#15
I'm running a system with 4 x 6970 (which require 1 8pin & 1 6pin each) and I'm using a Silverstone Strider 1500W. The PSU has 4 pcie cables with a 6+2pin and a 6pin.
My motherboard is an MSI 890FXA-GD70 for AM3 socket, that has 5 pcie slots(but 4 that can be used with a 1 slot gap for dual-slot GPU cards) and my case has 8pci expansion slots on the back.
So its fairly easy to run a 4 card setup even if those cards are dual slot.

What case are you using?

I'm using the In Win Ironclad ~100 euros from Amazon although I've seen it cheaper if you are prepared to look around a bit.

The cables on the Silverstone 1500W are about 50cm long and probably good enough for any top/bottom mount config that you could think of. Only problem is that the PSU is very expensive ~280 euros.
hero member
Activity: 575
Merit: 500
June 23, 2011, 04:26:44 AM
#14
Running 4x Sapphire 5850 Xtreme on a corsair 650 TX perfectly stable pulling 630W(around 85% eff) from the wall so there is still some headroom. I wouldnt try it with any other 5850s tho since the Xtreme cards seem to pull about 15-20w less than other 5850s.
member
Activity: 62
Merit: 10
June 23, 2011, 03:17:51 AM
#13
I use MSI 790FX-GD70 Socket AM3, that also has 5 pcie slots (4*x16,1*x1 physical size). Also I use 2xChieftec APS-800C connected with each other on green powerOn signal cable and black ground cable. Works like a magic.

Very nice.  That's a $200 board, right? D= DrMos, G= Gamer (orange box).  OR am I thinking of the 870A-GD70?

Nope. This one. Got two such for 86$ each (I live in Ukraine. They are still available for order).
All except GPUs: Mobo 86$ + CPU AMD Sempron 140 36$ + Kingston DDR3-1333 1024MB PC3-10600 (KVR1333D3N9/1G) 13$ + 2* Chieftec APS-800C 123$ = 381$ total
sr. member
Activity: 322
Merit: 250
June 23, 2011, 02:29:02 AM
#12
I use MSI 790FX-GD70 Socket AM3, that also has 5 pcie slots (4*x16,1*x1 physical size). Also I use 2xChieftec APS-800C connected with each other on green powerOn signal cable and black ground cable. Works like a magic.

Very nice.  That's a $200 board, right? D= DrMos, G= Gamer (orange box).  OR am I thinking of the 870A-GD70?


TJ11.  got it cheap and love it.

How much is cheap? I hear these suckers go for $600 to $700!
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