5x5770 on one motherboard

[Lacrimas]

Hello everyone.
I got some mining rig:

GB 770T-D3L /AMD770/AM3
SAPPHIRE HD5770 1G G5 DP BULK x4
2GB DDR3 1066 KINGSTON BULK
AMD Sempron 145 2.80GHz
PSU CM GX 750W APFC

OS: Ubuntu 11.04 Server (32-bit)

Currently i'm mining in hand-made case. GPU are clocked to 1050Mhz(gpu)/300Mhz(mem). Temperatures are around 69-72C. Wattage is 570W. Everything seems fine till now.
But now i got 1 more 5770 and wondering will it be some problem to install 5th videocard to this motherboard. Im not talking about temps and clocking etc. My point is on Wattage and Motherboard support. With wattage i cant see problem because 570W + ~115W = 690-700W max. and i have 750W PSU.

So what do you think about this?

Thanks alot!

[Lacrimas]

bump.

[mikethebodacious]

I think you would be overworking your power supply unit and get terrible efficiency if you did.  I think at this point in the game efficiency is VERY important so if I were you I would go get a 80-plus Gold 1000W PSU before throwing another card on your rig.  Depending on your 5770 card the required amps is only ~10 per card so don't worry about the 12V rail amperage so much.  What kind of 5770s are you rocking?  I got a few open box MSI Hawks from Newegg and I have to say they are the best 5770 on the market by far (amazing temps).

[Lacrimas]

I got SAPPHIRE HD5770 1G G5 DP.

Now 4 SAPPHIRE HD5770 1G G5 DP are working on 540W, thats mean that 1 5770 works on ~110-120W and temps are around 67-70C with OC 1050/300.

[mikethebodacious]

Wow, that's a nice OC for the Sapphires....Didn't know they could OC that well with that low of temps.  Is that the reference card model or the new shortened model?  I had the old one and could only hit 980MHz without going to 80C (maybe old thermal paste was the problem?)  Give it a shot if you want, I treat 5770s as filler cards though, putting them on rigs to use up the rest of the PCI-slots or PSU watts available.

[Big Time Coin]

You might kill your motherboard and/or your psu that way.  And if the PSU goes, it might take [random component(s)] down with it.  Not recommended, stick to 4 cards.

[wigglyuk]

your gonna have to upgrade to 1000W PSU just to be safe...

[Lacrimas]

mikethebodacious: i dont know exactly is this a new series or not. This is a picture of VC: http://www.jmt.bg/images/products/8867_10155.jpg

To All: Ok, thanks guys, i guess i will stop on 4 GPUs on this rig.

[worldinacoin]

Just wondering is 4 GPU the limit or optimal?  Can there be higher density rigs that are stable?  What will be the normal limiting factors.

[mikethebodacious]

mikethebodacious: i dont know exactly is this a new series or not. This is a picture of VC: http://www.jmt.bg/images/products/8867_10155.jpg

To All: Ok, thanks guys, i guess i will stop on 4 GPUs on this rig.

Yeah that's the newly redesigned Sapphire 5770 with Vapor-X cooling fan on it.  Sapphire really does make some solid cards