Dabadger84
 

ArcticParadise
Mem temps on my 3090 FTW3 after installing the Hybrid kit have all gone up. In my case, GPU2, MEM1, MEM2, MEM3 and PWR4 all increased in temperature versus running on air. The worst offender was MEM1 with a +5C increase under full load.
 
Would be curious to hear what others have experienced as comparison.

 
Every person I've seen that has higher temps was the result of a bad mount or the pump being defective on the Hybrid cards/Hybrid kit installs.  It doesn't take much to negatively effect load temps, and it wouldn't necessarily show up in idle temps.  Try remounting it - or just take it apart to the point where you would separate the PCB from everything else, then redo all the screws in the order it says to, making sure they're at proper tension.  
How are you running the Hybrid radiator, does your case have good airflow, positive pressure (more intake than exhaust)?  All of that is important... also, if you have the Hybrid radiator as INTAKE, that's why all of your temps are higher except GPU core (if that's lower), your intaking hot air from the GPU radiator which is then being fed through the GPU's shroud.  The air coming out of that radiator can get in the 34-41C range in my testing - not a good temp to be intaking in to your case.

rjbarker

Dabadger84

ArcticParadise
You're 100% correct. It's airflow. I've had excellent airflow prior to the installing the rad, I had to stick it on the intake, in front of a pair of 200mm fans on a Coolermaster H500 case. Temps on Mem1 were up to 9C higher but after I shifted the rad upwards about an 40mm to open up more airflow past the bottom and increased the card blower fan speed to 90% from 75%. Bang, temps dropped about 3-4C under full load on everything except GPU1, but still sitting about +5C on Mem1 versus air cooled. Next is to try external mounting my radiator completely. You're totally right about the intake air getting too warm for everything else.
I'll try to remember to report back with results for those who are interested.

 
Yeah we have a few folks that are going around telling people to mount their GPU radiator as intake when that's actually a horrible idea for the rest of your system, I try to keep an eye on threads, at least on this forums, to post factual evidence that having GPU radiator as intake instead of exhaust is actually a really bad idea for the rest of your internal components, but I missed some every now & then.  It's like "Yes, let's mount the GPU radiator as intake to get slightly cooler temps on our GPU die at the cost of making EVERYTHING ELSE in the system deal with air that's between 10-27C hotter that it would have to deal with with regular air being intake." Just makes me laugh.  People don't realize, the air a CPU radiator will be exhausting, unless you have a super-high core count HEDT or Threadripper CPU, is never going to be anywhere near as hot as what's coming from the GPU radiator.  My CPU in particular gets up in to the 170-190W draw range under full load.  Gaming, it's typically between 80-120W, that's nowhere even in the ballpark of what the GPU is going to be pumping in to that radiator - add to that the fact that most people's CPU radiators are as big or bigger than the regular Hybrid radiator (240mm), while it is dealing with 350-500W of heat vs the CPU's smaller amount... it just makes zero sense. 
Yeah, having the CPU radiator as intake will result in 1-3C higher temps inside the case and that air will be used as intake for the GPU radiator, but would you rather have a GPU core that's 1-3C warmer, or having your CPU VRMs, RAM, M.2s, hard drives, GPU VRMs, and all other internal components dealing with air that could be between 32-41C coming out of that GPU radiator under gaming loads.
To me it's a no brainer.  But for people who it's their first time building or they've never built with AIOs before, it's a real issue and concern, and it really irritates me that there's people spreading bad information and acting like it's actually the right thing to do.

Been building custom loops for years....radiators should always be intakes period!! Not sure about some hybrid mish mash....but you ALWAYS want fresh room temp air pushing thru your fins...and for heavens sakes low density fins are the way to go !!!
My loop has 3 radiators....4*...3* and 2* all intakes ....the front of the case also has 3 dedicated intake fans (no radiator)....so thats a total of 12 fans all forcing nice cool air into the case creating "positive pressure" which is expelled out the top back thru a single 140mm exhaust fan.....with this type of set-up warm air in the case is a moot point.....
I would never recommend nor build a system using radiators as exhaust....defeats the purpose of a radiator running warm air thru em!!
Set up a proper dedicated exhaust fan or systems of a few exhaust fans, but always run the coolest air possible thru your rad!
my 9900k whether running 5 Ghz or benching at 5.1 - 5.3 Ghz stays cool....my 3080FTW3 running at 2100 Mhz sustained never goes above 42c ....my Board is cool as cucumber!
D5 Vario Pump set to run at 3200 RPM

rjbarker
Rads are heat exchangers.....moving the coolest air possible thru a heat exchanger is going to provide the best possible cooling to your liquid (working properly your liquid should be reflective of room ambient temp), therefor providing opimal cooling to your primary components (CPU n GPU with Water Block).
Any slight increase within the case is "exhausted" through your dedicated exhaust fan.
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The temps on modern mobo in relation to Mosfets, Voltage Regulators and Northbridge are not extreme enough to cause issues (unlike the previous HEDT Boards whereby the Southbridge and Northbridge did get very hot and required some sort of active cooling or a mobo Block) besides they will also benefit by having the air movement over top of them as it moves thru the rad (the air moving from the rad isnt that warm at all).
 
But this seems to be an ongoing debate (not in the all WC'ing loop world though), seems it comes up more with the hybrid n aio coolers.
I do recommend setting it up your rad / fans as intake, just be sure you have at least 1 decent fan (140mm optimal and near the top) as an exhaust.
Also remember not a single case is "airtight"....there are generally a ton of cracks n crannies and vent grills to push out warm air when setting up a "positive pressure" case!
Just set it up however you like, in some situations the case size alone will restrict you to a certain orientation. I dont have this issue as my Corsair 900D Case is a monster ;)