I would run them in serial, I have always ran my SLI systems in serial and have never had any problem, and have always maintained very good temps.

I would go serial in your case.  The only thing parallel does is reduce the temp difference between the GPUs, but that is not necessarily better, especially if you have a CPU block in the same loop, because splitting the flow results in pressure drop and your whole system may run a bit hotter.  If it's a GPUs only loop, then it doesn't really matter.

Thanks everyone for your input and help

I'd also opt for a serial order, most people have no trouble with it ... unless they are running the nuclear hot 400 series GPUs
 
I am actually in process of upgrading to 670 SLI from a single GPU setup and decided to connect the GPU blocks with a solid adjustable link from Koolance like this (1 slot spacing between cards - not sure if that will fit like I think it will):
http://www.performance-pc...&products_id=25782
 
... perhaps I should ordered 2-3 slot spacing adapter as well ... starting to doubt myself ...
 
EDIT:
doh! I counted the bypassed slots wrong ... I counted 1 slot space between them but I was imagining each card stretching across 2 slots (like with stock air cooling housing) ... forgot that with full cover water blocks they become a single slot cards
had to order the 2-3 slot spacing adapter LOL! like this:
http://www.performance-pc...&products_id=25783

true about the potential problems rising from troubleshooting the GPUs while they are connected with solid solid link be it a bridge or solid connector (Dual VID adapter, both Koolance and Swiftech make them). for instance on my former Z68 FTW board the jumpers for disabling PCIe slots didn't work at all (zero effect when jumpering the "disabled" pins)... switches on Z77 FTW should work fine though, I have same ones now on MVE,
 
I took my chances, wanna try the solid link first and see for myself how it will go. I decided not to use any bulky SLI water bridges as I couldn't figure out from store descriptions which ones were parallel and which ones serial .. or which ones were all mixed (joined chambers inside)...
 
One thing I couldn't figure out though was the slot spacing I need for DUAL VID adapter LOL! at first ordered a single slot adjustable bypass adapter, today ordered the 2-3 adjustable slot adapter too ... will see
 
Initially my cards will be installed in physical slot locations #1 & #4 (counting the "empty space" as slot #2) for native 8x/8x as per Asus recommendation which suggests not using the PLX for 2-way SLI ... I might in future move them to other config (8x/16x closer together physically) just to see how they perform while one card goes through PLX or so ... from my own experience the whole NF200/PLX bridge fuss doesn't seem to make any visible difference for 2-way SLI (used to have Z68 FTW & Z77 FTW in past), will see how it goes with MVE board.
the switch bridges perform very well however for tri-SLI (or perhaps for Quad-SLI, but never tested such).
 

EVGATech_DaveB

Actually the dual spacing is needed.  The block may be single slot, but the DVI's are stacked, and as such even under water, they cover up 2 slots.  my 680's are the same way  :(

Also, I personally do NOT recommend using those types of connectors.  In and of themselves there is nothing wrong with them.  My reasoning for it is this.  If there is a solid connector and you ever have a GPU issue, troubleshooting can be an issue.  Some say "jumper off the slots" and that can help, but it doesn't always remove 100% of the issue.  In which case its drain the loop pull both cards, remove the connector, jerry-rig it back together minus 1 card, refill, retest etcetcetc.  Personally.  I run a piece of malleable hose between them, when I had a issue with ym 580s a couple years ago.  I powered off, loosened both in their slots, bent one slightly so the bus would sit on top of the slot and retested.  I did it with both cards, and narrowed it down, without draining, made things a LOT easier.

It does not look as good, no argument, but it just made things easier for me.  I don't like to plan for failures, but at some point, nothing lives forever..... and sometimes crap can just happen.

very interesting and looking very nice
 
I don't fully comprehend the direction of water flow in your GPu setup, but regardless it must work and looks good hehe
 

eternitykh

i am running parallel for looks :P not performance, but i'll be upgrading my pump after new years, got my pc funds all tied up for more important things in life right now, haha.

and im using bitpower's crystal links, solid AND clear!

check my modsrigs for pictures.

hehe, gotcha, good catch
 

eternitykh

hahaha thanks, most look at it and go wth!?

the bottom 2 short tubes are just drain plugs, LOL they lead to nowhere, it just tricks people :P

aww now my secrets out

nice!! the rig is looking sharp there, buggy.