Are you seriously saying that a 780 is only 20% faster than a 580 for rendering? That doesn't sound like a worthwhile upgrade.

For me it is great upgrade and it is the fun to build it.
16% better rendering time and 100% more ram, upgrade psu starter for less than a gtx1080. Sweet !
And maby in near future a can use all the gpu power better than with todays software.

Serious ?
Using a old 1366 mobo 2016 ?
SR-2 is a old megaperformance mobo.
And for me it is still the best.

A did not buy a 2x22 cores intel working at 2400mhz.


Often a new cpu family offer 5-20% better performance and a lot better watt/core.
People buy it.
New cpu, new mobo, new ddr. Are they not serious.

The SR-2 isn't actually that great, even OC-ed. My seat of the pants perception is that my machine is noticeably more responsive with the non-OC-ed Supermicro X8DTH than it was with the OC-ed SR-2 (all other components exactly the same, as per the sig). And the X8DTH setup runs significantly cooler with 2 fans fewer.

A lot of stuff is better than SR-2 Gordon and it is ok
I own a few Supermicro X8DT and it as u say. probably a better choice.
my X8DT only have 1 pcie x16 so multigpu is out.
It is Quiet, much better with heat, the cpu fans runs very slow     
And the best: X8DT also handle the 96GB of ram better than SR-2.
  
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 

X8DTH series has 7 PCIe slots, same as the SR-2, although you lose 2 DIMM sockets if you want to use a full length card in slot #1. You may be able to work around that by using ultra low profile DIMMs.

Using 7xPCIe extender Cables, so no problem with ram or ramslots.  
I google X8DTH.
a very nice mobo.

My Supermicros is X8DTi, 1 pcie 16x.
 
I building this 7xGPU/SR-2  ( for my wallet to ) i dont have to buy Another mobo 
and it is fun to find parts for it, also new parts like the nice multiPSU-card on ebay.  
Homebuild welded frame/chassi and some other stuff.
I think it will peform outstanding results.
Will do a lot of tests when finisch and put them up, bios settings also.
 
 
 
 
 
 
  
 
 
   
 
 
 
 
 
 

The other advantage of the X8DTH is that it is a smaller motherboard, and the top slot fits against the top slot on the case. With the SR-2, the motherboard's slot #1 actually lines up against slot #3 on the case, so you lose 2 slots on the case. Which in turn means you could use a PCIe ribbon cable and have the 5th dual slot GPU in the case. You will need something proprietary to get the last 2 GPUs in if you really want to run with 7. You will also almost certainly need to slow down PCIe to v1.x speeds if you are using PCIe ribbon extenders.

It is a homebuild Mining style chassi.
My multi-Fermi GPUs did not work with pcie 100 so probably not the gtx780.
But am not there yet.
Probably slow down PCIe to 88-92 to get it to run ok.
It is going to be a lot of Bios testing and crashes with total resets  
But hopefully it will work.
   
 
 
 
 

Note that I am not talking about PCIe base clock speed but the protocol version. To use PCIe ribbon cable extenders you have to use a motherboard that will let you reduce the PCIe protocol verision down to v1.0 or v1.1. PCIe 2.0 and later will not work.

More pics on my build.
The 3x120mm 80mm radiator is replaced with a fat 3x140 80mm radiator
So 3x140 3,15" radiator and 4x120 3,15"  in the front .
Welding the frame finish this weekend, and paint :-)
The watercooled thermelectric watercooling machine have to wait 1-2weeks, waiting for 6x12cm alublock from ebay.
This machine will have 2x850watt     
Got 3x Phobya fast Waterpumps + a lot of
extra 3x120 thin radiators, and lot of  1/4 silicone hose.
i Think that 2x1200 watt PSU will fit in the pc.