Maximum # of 7970 GPU's a Lepa 1600 PSU Can Handle ?

[forexmasterja]

Hey,

I have been reading alot of articles here mentioning Lepa 1600w PSU's for rigs over 5 cards.

I'm wondering if this PSU would be able to handle 5-6 7970 GPU's for mining both bitcoin and scrypt ?

Anyone have personal experience with this number of 7970's ?

[BlazinBeaches]

My 6 7970s with mobo/cpu/ram/etc suck 1600+/- watts from the wall.  I would do 5 max on that psu unless you have a separate psu for mobo/etc.  But that's still cutting it close.  However you configuration try to leave at least 15% breathing room for the psu.

[forexmasterja]

My 6 7970s with mobo/cpu/ram/etc suck 1600+/- watts from the wall.  I would do 5 max on that psu unless you have a separate psu for mobo/etc.  But that's still cutting it close.  However you configuration try to leave at least 15% breathing room for the psu.

Ok cool sounds like it will do 5 easily then, whats your setup ? Mboard & cpu ?

[PeeJWeeJ]

A 7970 can take 300 W. (75 from pci-e, 75 from 6pin and 150 from 8pin). If you want to run 5 cards on a 1600W power supply make sure your MB, CPU and RAM use as little power as possible since you potentially only have 100W of guaranteed headroom.

[grobbes]

7970s are voltage unlocked so drop it to 1000 mV and adjust clocks and you should have no issue with 6. I run 4x7950s locked voltage under 1000w.

[systic]

I had to decide recently myself and went with 2 psu's. ne 60$ silver 750 for 1x7970 and mobo/cpu and another rosewill 1300 for 2x7950s and 2 7970s. Total was 260$ new from newegg for pus power.

[PeeJWeeJ]

I had to decide recently myself and went with 2 psu's. ne 60$ silver 750 for 1x7970 and mobo/cpu and another rosewill 1300 for 2x7950s and 2 7970s. Total was 260$ new from newegg for pus power.

I use the same rosewill PSU, it's worked like a dream and at an insanely good price!

[forexmasterja]

I had to decide recently myself and went with 2 psu's. ne 60$ silver 750 for 1x7970 and mobo/cpu and another rosewill 1300 for 2x7950s and 2 7970s. Total was 260$ new from newegg for pus power.

I use the same rosewill PSU, it's worked like a dream and at an insanely good price!

How many cards are you running though ? and are you using 2 psu setup like he mentioned ?

[meowmeowbrowncow]

The Lepa 1600 has 2 20 Amp rails and 4 30 Amp 12V rails.


I would imagine this to mean that the 2 20 amp rails are limited to 240 Watts each.


The problem this leads to is that 160 Amps at 12V is well over the 1600 Watt rating for the PSU.  So, there is a limitation being obscured by the fact it has multiple rails.



The multiple rail business complicates a setup - so Lepa isn't as attractive to me.

[PeeJWeeJ]

I had to decide recently myself and went with 2 psu's. ne 60$ silver 750 for 1x7970 and mobo/cpu and another rosewill 1300 for 2x7950s and 2 7970s. Total was 260$ new from newegg for pus power.

I use the same rosewill PSU, it's worked like a dream and at an insanely good price!

How many cards are you running though ? and are you using 2 psu setup like he mentioned ?

4x 7950s along with the MB. I haven't seen better for $260.

[forexmasterja]

My Lepa 1600 work with 4x7990 - can push up to 1800W in long term and up to 2000W in short (at wall).

Now this is really getting confusing on the one hand have you saying you have 4x7990 working but that previous post about the multiple rails has me confused.

How exactly does the multiple rails affect the system setup when doing like 6 cards ?

[mirny]

My Lepa 1600 work with 4x7990 - can push up to 1800W in long term and up to 2000W in short (at wall).

good to know i'm planning to connect 3x7990 to Lepa 1600W or Enermax 1500W or Master Cooler 1500W
actually wich 7990 are you using, gigabyte, msi, asus or sapphire?
and if it's not a secret how many mHash/s is it pulling?

[crazyates]

My Lepa 1600 work with 4x7990 - can push up to 1800W in long term and up to 2000W in short (at wall).

Now this is really getting confusing on the one hand have you saying you have 4x7990 working but that previous post about the multiple rails has me confused.

How exactly does the multiple rails affect the system setup when doing like 6 cards ?

Actually those two go hand in hand pretty well. There are 4 rails that supply 30A each. If you hook up each 7990 to it's own 30A rail, you're all set.

[forexmasterja]

My Lepa 1600 work with 4x7990 - can push up to 1800W in long term and up to 2000W in short (at wall).

Now this is really getting confusing on the one hand have you saying you have 4x7990 working but that previous post about the multiple rails has me confused.

How exactly does the multiple rails affect the system setup when doing like 6 cards ?

Actually those two go hand in hand pretty well. There are 4 rails that supply 30A each. If you hook up each 7990 to it's own 30A rail, you're all set.

Ok but as it relates to the 6 7970's are you saying the multiple rails on the Lepa is bad ?

[spawnbsd]

I'm use a VTX 7990 (I think is the same as powercolor). 4x7990 hashing ~ 4600 Mh/s in scrypt with this setings: core 835 @ mem 1375. My first 4 cores are undervolted to 0.925 and second 4 is default voltage (not accesible at bios).

Not trying to take this thread off topic, but I'm looking at building a similar setup with 4 * 7990. What OS are you using ? How are you cooling them ?

[crazyates]

Actually those two go hand in hand pretty well. There are 4 rails that supply 30A each. If you hook up each 7990 to it's own 30A rail, you're all set.

Ok but as it relates to the 6 7970's are you saying the multiple rails on the Lepa is bad ?

Potentially. Depends on how hard those 20A rails are being pushed.

[xide]

one 7970 on LTC or scrypth depends on gpu/vram clock can spend even 350w
if you plan scrypth mining max 5  cards for lepa 1600 with undervolted...
before you buy cards check if there arent voltage locked ...new series with BE -BOOST EDITION most are locked..