Make sure you have the black gasket in.  The black one has different dimensions to increase and stabilize the pressure used to help seal the block.  I would also check the cold plate screws to make sure they are secure.  I would also do a once over on the screws that mount the plexi covers to each of the blocks for the front and rear.  I would recommend tightening those down to make sure the seal is as tight as can be.  
 
Once you start the process of converting to the Optimus block, the instructions on the Kingpin HC are very valueable.  Keep all the screws removed in a small container so you don't loose them.  I'd also have a small container if possible to try and save as much as the thermal putty you can in case you need to rma the block back to EVGA.  The tape on the pcb holding original shroud is pretty tough but take your time prying it safely apart.  If you have a plastic pry tool use it from different angles to help loosed up that tape.  Do not use a metal tool to do this as you may damage your gpu.  Also, when taking off the fan shroud be aware of the wires and gently remove the plug for the fans from the port on the gpu.  There is limited space there so take your time and don't rush or you could end up damaging the plug or port.  
 
Also, some of the screws you will use to mount the gpu to the block will need to be tightened up to help seal the block.  You will see these when you are working on the block as they are close to the gaskets.  Once you have the gpu lined up and pretty much mounted I would go back and increase pressure on those screws to help make sure you have a good seal.  These will be the screws that pass through the plexi to the other side of the block.  
 
I would have a spare set of thermal pads from Optimus if possible.  The ones that come with the block are thin so they don't like being taken apart or they are fragile due to the thickness/material used.  
 
Also, the online instructions as to tensioning the block around the gpu are the more current version.  I don't know if they made a running change to the printed one they supply.  When lining up the blocks, take your time to evenly distribute the tension so that you don't warp or over tighten the block causing the gpu to flex.  As you tighten down the block to the gpu, be mindful to check the gpu board to make sure it's not warping/flexing.  
 
The torx head screws can be a pain to work with if you are rushing.  Make sure to fully seat the torx wrench into each screw as you are either fastening or unfastening them to make sure you don't damage the heads.  
 
The most important thing is to air pressure test the block once you assemble it on the gpu.  I would also recommend doing a test that is longer than what you would normally do since the block has an active rear plate.  You want to find the leaks if any early on before you put coolant into it or mount it into your pc if possible.  
 
Lastly once you have your block assembled and ready for installation, make sure you take into account additional bracing or support.  This block is really heavy and additional should be used to help reduce stress on the gpu and mobo.  The block does not extend the entire length of the gpu pcb so there is a possible flex point that would be a concern near the signal outputs on the gpu.  I still don't know why the block does not extend all the way, but since it doesn't it really would put a strain on that one section of the pcb that is unsupported by the block plates.  
 
There are a few posts here that go into build notes or things of concern so I would read through the post starting in December of 2021 to current to see what else you can gather to help you with your build.  
 
 

Wow, thanks very much @Gotspeed_2000 ! Didn't expect such details helps a lot!  Bookmarked and saved and will be printed out when i'm ready to do the work for sure. Will do an industrial looking loop with EK's ZMT soft tubes because it's not a pia like hard tubes for sure especially for a beginner like me.
What do you recommend as a reliable fluid? Something clear i reckon. My goal is not only industrial look but also industrial in terms of maintenance.

AtozGlue

Zvedza
Got my block today after a few delays. Looks amazing except the usual suspect. 
Is this ok? Ive been following this thread for a bit and have seen some issues regarding the backplate being warped/curved etc. Im able to press down gently and it straightens out easily, but have not mounted or leak tested it yet.

bend doesnt look so bad. When you mount it, it'll flatten out. Mine was way worst than this.
 

Yeah, mine looks similar. Maybe even a little bit more bend.

fragility_V1

Zen_Punk

OCF4n
Wow, thanks very much @Gotspeed_2000 ! Didn't expect such details helps a lot!  Bookmarked and saved and will be printed out when i'm ready to do the work for sure. Will do an industrial looking loop with EK's ZMT soft tubes because it's not a pia like hard tubes for sure especially for a beginner like me.
What do you recommend as a reliable fluid? Something clear i reckon. My goal is not only industrial look but also industrial in terms of maintenance.

I personally like the DP Ultra Clear, from Aqua Computer.

I've been using Mayhems X1 Clear concentrate for several years, no issues:
https://modmymods.com/mayhems-x1-v2-concentrate-coolant-clear-250ml-mx1c250mlcl.html
 

Yeah, I heard about that fluid from Aqua Computer. it's pretty reliable. But Mayhems is a concentrate and not a pre-mix like DP Ultra Clear i reckon so i would still need to buy some distilled water. Right?

Nereus

fragility_V1

Zen_Punk

OCF4n
Wow, thanks very much @Gotspeed_2000 ! Didn't expect such details helps a lot!  Bookmarked and saved and will be printed out when i'm ready to do the work for sure. Will do an industrial looking loop with EK's ZMT soft tubes because it's not a pia like hard tubes for sure especially for a beginner like me.
What do you recommend as a reliable fluid? Something clear i reckon. My goal is not only industrial look but also industrial in terms of maintenance.

I personally like the DP Ultra Clear, from Aqua Computer.

I've been using Mayhems X1 Clear concentrate for several years, no issues:
https://modmymods.com/mayhems-x1-v2-concentrate-coolant-clear-250ml-mx1c250mlcl.html

I only ever use clear coolant.
 
Distilled water and a silver coil has worked for me in the past, but it does need to be drained and refreshed occasionally to keep it clear from microbes.
 
I recommend avoiding EK-Cryofuel (clear), it turned cloudy soon as I put it in my loop and didn't clear for some time, and left a ring around the inside of my reservoir that was a mission to clean. I've read a number of people had this same issue with the clear Cryofuel, but others have had no such issues, so ymmv. Maybe I got a bad batch.
 
I've since been using Corsair's Hydro X Series XL8 coolant (clear) and have had no problems with it, so that's my recommendation, for whatever it's worth.
 
 

Yes, i saw the amazon reviews on the EK fluid. It turned brown on some people after some time lol. Unfortunately i didn't see any reviews on the Corsair one. So i don't know the long term experience from people.

OCF4n

fragility_V1

Zen_Punk

OCF4n
Wow, thanks very much @Gotspeed_2000 ! Didn't expect such details helps a lot!  Bookmarked and saved and will be printed out when i'm ready to do the work for sure. Will do an industrial looking loop with EK's ZMT soft tubes because it's not a pia like hard tubes for sure especially for a beginner like me.
What do you recommend as a reliable fluid? Something clear i reckon. My goal is not only industrial look but also industrial in terms of maintenance.

I personally like the DP Ultra Clear, from Aqua Computer.

I've been using Mayhems X1 Clear concentrate for several years, no issues:
https://modmymods.com/mayhems-x1-v2-concentrate-coolant-clear-250ml-mx1c250mlcl.html
 

Yeah, I heard about that fluid from Aqua Computer. it's pretty reliable. But Mayhems is a concentrate and not a pre-mix like DP Ultra Clear i reckon so i would still need to buy some distilled water. Right?

Yes, that Mayhems is a concentrate, so you will need distilled water.  Give you some flexibility to mix it how you want.  They also do sell a pre-mix of the same thing.

B0baganoosh
*reading this while knowing I have clear EK Cryofuel in my computer at home right now*
 
uhhhh....well...guess I'll have to keep an eye on that. I haven't had any issues yet, but I'll keep an eye on it. I've been using the Koolance 702 at work for a couple years now and so far haven't had a single issue. We use quite a bit of dissimilar metals too (well, copper and aluminum mixes).

Ironically ive had zero issues with my red ek cryofuel in my system for the 2 years its been in there, but my clear cryofuel started to cause growth, was prob just a bad batch.
 
Also optimus got back to me today and said what you all have said, they think its perfectly fine, which is nice to hear. Hopefully can throw it all on this weekend. 

Gotspeed_2000
Make sure you have the black gasket in.  The black one has different dimensions to increase and stabilize the pressure used to help seal the block.  I would also check the cold plate screws to make sure they are secure.  I would also do a once over on the screws that mount the plexi covers to each of the blocks for the front and rear.  I would recommend tightening those down to make sure the seal is as tight as can be.  
 
Once you start the process of converting to the Optimus block, the instructions on the Kingpin HC are very valueable.  Keep all the screws removed in a small container so you don't loose them.  I'd also have a small container if possible to try and save as much as the thermal putty you can in case you need to rma the block back to EVGA.  The tape on the pcb holding original shroud is pretty tough but take your time prying it safely apart.  If you have a plastic pry tool use it from different angles to help loosed up that tape.  Do not use a metal tool to do this as you may damage your gpu.  Also, when taking off the fan shroud be aware of the wires and gently remove the plug for the fans from the port on the gpu.  There is limited space there so take your time and don't rush or you could end up damaging the plug or port.  
 
Also, some of the screws you will use to mount the gpu to the block will need to be tightened up to help seal the block.  You will see these when you are working on the block as they are close to the gaskets.  Once you have the gpu lined up and pretty much mounted I would go back and increase pressure on those screws to help make sure you have a good seal.  These will be the screws that pass through the plexi to the other side of the block.  
 
I would have a spare set of thermal pads from Optimus if possible.  The ones that come with the block are thin so they don't like being taken apart or they are fragile due to the thickness/material used.  
 
Also, the online instructions as to tensioning the block around the gpu are the more current version.  I don't know if they made a running change to the printed one they supply.  When lining up the blocks, take your time to evenly distribute the tension so that you don't warp or over tighten the block causing the gpu to flex.  As you tighten down the block to the gpu, be mindful to check the gpu board to make sure it's not warping/flexing.  
 
The torx head screws can be a pain to work with if you are rushing.  Make sure to fully seat the torx wrench into each screw as you are either fastening or unfastening them to make sure you don't damage the heads.  
 
The most important thing is to air pressure test the block once you assemble it on the gpu.  I would also recommend doing a test that is longer than what you would normally do since the block has an active rear plate.  You want to find the leaks if any early on before you put coolant into it or mount it into your pc if possible.  
 
Lastly once you have your block assembled and ready for installation, make sure you take into account additional bracing or support.  This block is really heavy and additional should be used to help reduce stress on the gpu and mobo.  The block does not extend the entire length of the gpu pcb so there is a possible flex point that would be a concern near the signal outputs on the gpu.  I still don't know why the block does not extend all the way, but since it doesn't it really would put a strain on that one section of the pcb that is unsupported by the block plates.  
 
There are a few posts here that go into build notes or things of concern so I would read through the post starting in December of 2021 to current to see what else you can gather to help you with your build.  
 
 

About that tape on the pcb. Do i need to completely remove all the residue (with alcohol) after i take the shroud apart? Or did you just leave it there?

AHowes
3 years plus on my last flush (cause of upgrade) and the Mayhems X1 clear still was clear haha. Didn't flush the 4 rads or blocks and just refilled and guess what.. Still clear months later!

Never had it this easy and have been water cooling pc's since it was a thing 2 decades ago!

1750ml of distilled water per 250ml of coolant.. mix for a min and go!

For "Sub Zero Cooling down to -8c) - mix 250 ml of coolant to 750 ml of Water. (makes 1 Ltr in total).

I buy it from https://www.performance-pcs.com/

and its cheap too

OCF4n

AHowes
3 years plus on my last flush (cause of upgrade) and the Mayhems X1 clear still was clear haha. Didn't flush the 4 rads or blocks and just refilled and guess what.. Still clear months later!

Never had it this easy and have been water cooling pc's since it was a thing 2 decades ago!

1750ml of distilled water per 250ml of coolant.. mix for a min and go!

For "Sub Zero Cooling down to -8c) - mix 250 ml of coolant to 750 ml of Water. (makes 1 Ltr in total).

I buy it from https://www.performance-pcs.com/

so this one:
https://www.caseking.de/Mayhems-X1-UV-Clear-Blue-1000ml-WAZU-282.html?tplview=desktop 
? This should be a pre-mix i reckon.

Yes thats the ready mix... in blue.. uv reflective.

33*C max gpu temp with 25*C water on port royal holy shiz. EVGA AIO and waterblock were giving me 48*C+
This is what i was hoping the evga block would do. My rig isnt as nice as some of your guys' builds, but figure id throw it in anyway. 

Note my high tech gpu support bracket. Also like said above, this block killed my flow, but still good enough for now, def need to add another pump in the loop somewhere. 

what sort of high end sound card is it that still uses an internal slot? figured most DACs were USB by now

Zen_Punk

zippytek
what sort of high end sound card is it that still uses an internal slot? figured most DACs were USB by now

It’s the HT Omega eClaro 7.1 pci-e.
I like it because it can push, a nice set of stereo headphones.

gotcha, i pinged my audio friend to see if he has suggestions for a nice USB DAC that is in this class. just curious myself but will share whatever he sends back. have a good one

loveha
Look into Schiit audio. Everything for every price point to push 600 ohm cans.

The Modi / Magni combo is the entry level for schiit:
https://www.schiit.com/products/modi-1
https://www.schiit.com/products/magni-1
 

Nereus
lol.. I assume they have a good reputation, but I can't help laughing a little about buying high end audio from a company named 'schiit audio'.

Oh they lean into it.  Feels like the company was named during a late night of drinking, and someone said "duuuude, you should totally name it that, that would be hilarious"