Zotac 5090 + Alphacool waterblock issues

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Hi Everyone

I've run into issue with my new build which is quite annoying, hoping for some advice here.

I finished my new build/loop about a month ago, everything seemed fine at first but I've noticed random crashes in few games, mainly in Indiana Jones, Anno 117 Demo and Broken Arrow.

Crash is always the same, black screen I can hear the game/sound in the background but can't do anything apart from shutting down, it does not recover.

In Windows log nvlddmkm error Event ID 14 flowed by 152.

At first I thought it was software issue but after wasting ton of time with drivers, settings, updates, windows ect, you name it I've tried it i found that the issue is with hardware/power delivery.

When my 5090 has waterblock on (Alphacool Core) temperatures are great, generally 50 to 60C roughly, maybe few degrees more but never saw more than 65 on either GPU or memory.

however when I run 3D Mark or any game for that matter and watch power draw it only draws full power for a moment, during first minute or so it goes to ~ 575W but gradually drops from there.

I made bunch of tests using HWinfo and GPUZ and I can see in the logs how TDP gradually drops from 100% down to # 78 ish

In 3DMark this will go up and down but I tried resting on static scene eg specific place in game and same thing happens and eventually it crashes.

Now here's a kicker, when I put the stock cooler back on everything is fine, card is much hotter tops out at 80/82C but still draws full power, 3DMark gets higher score and most importantly zero crashes in games.

I've been going back and forth with WB and stock cooler, changed paste, thermal pads etc but same thing, stock cooler runs hotter but works fine and with WB installed I get power limiting and crashes.

I have noticed that in GPU Z card runs in thrm limit in PerfCapReason, when this happens I can see drop in power in logs but GPU/memory are still sitting at circa 55C so what is overheating ?

Neither GPU Z or HWInfo are showing any other temp readings.

No idea why is this happening, WB is correctly installed I've been doing WC builds for 10 years and lets be honest it's not that hard to install a WB.

What could be causing this ? this is my first Alphacool block I used mainly EK before and never had this problem.

Could this be some flaw in WB design or maybe it's my setup ?

Perhaps WB is heating up because I have 420 rad directly below ?

I'm including screenshots, GPU Z with thrm redout, this was during 3DMArk stress test with WB on, never happens with stock cooler and my setup/airflow.

Second GPU Z screenshot is during 20 loops 3D Mark stress test with stock cooler, solid green line no limits other than power.

For now I'm back on stock cooler, considering buying Bykski WB but not sure tbh

EDIT: Forgot to mention that I tried same testing with a different PSU/cables and results are same.

 
Haven't watched it all, but I saw this today:


There's a follow on video in the description as well, plus from comments made in the comments section, it appears Alpha Cool blocks might not be the best idea?
 
PS: I've used a Bykski GPU block a few years back, I was very impressed with the quality especially for the price at the time.
 
Haven't watched it all, but I saw this today:


There's a follow on video in the description as well, plus from comments made in the comments section, it appears Alpha Cool blocks might not be the best idea?
Hmm that's interesting, temps on my 5090 are looking good but 50 series has no hot spot temperature anymore.
Tbh it looks like it is overheating something that's not being reported via software, at least software I'm using.

I might have another go and try what he did in the video and use the retention backet from stock cooler to mount the waterblock and see what happens.
 
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I wouldn't risk it imo, might risk shorting something or killing the card. Not the first time there have been issues with alphacool blocks.
 
I would never buy alphacool again!

Loads of issues with wrong thickness thermal pads! Same happened with my RTX 4080!!

Only thing I can advise is to ensure all components on the GPU are making good contact!
 
I wouldn't risk it imo, might risk shorting something or killing the card. Not the first time there have been issues with alphacool blocks.
I was under the impression they are pretty good, I’d go with EK as usual but they don’t make one for Zotac 5090 solid.
Only other option I found is Bykski.
 
I would never buy alphacool again!

Loads of issues with wrong thickness thermal pads! Same happened with my RTX 4080!!

Only thing I can advise is to ensure all components on the GPU are making good contact!
Yea I did it 5 or 6 times now, using pads provided with block and stock cooler.
I just orders new pads and few other bits.
I will remove the radiator from the bottom and put new pads on, see if that helps.
Would you say waterblock from Bykski would be better quality ?
 
Yea I did it 5 or 6 times now, using pads provided with block and stock cooler.
I just orders new pads and few other bits.
I will remove the radiator from the bottom and put new pads on, see if that helps.
Would you say waterblock from Bykski would be better quality ?
Might be better quality, but it might also be cheaper to just get thinner thermal pads.

However, depending how much you paid for the alphacool block, it might be worth returning and going the Bykski route..
 
Not sure how return would work, I bought it on 08/08 and had to wait for some other bits to build it.
Tying to find what is the problem took me best part of two weeks.
I’ve ordered new pads and will give it another go, I’ve noticed that using thinner pads on the front helped with GPU temps.
I think they need to do more testing before releasing those blocks.
 
Not sure how return would work, I bought it on 08/08 and had to wait for some other bits to build it.
Tying to find what is the problem took me best part of two weeks.
I’ve ordered new pads and will give it another go, I’ve noticed that using thinner pads on the front helped with GPU temps.
I think they need to do more testing before releasing those blocks.
Issues when WB is installed, no issues when stock cooler is put back on. That's enough for an RMA.

I think it's too risky trying new pads etc. It shouldn't have these issues to begin with, not worth potentially killing the card.
 
I’ve had no issues with my Alphacool block on my 5090 (gaming trio).

I’m not sure how the block itself would impact power delivery?
 
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A little update, I decided to give it another go with new pads/paste all around and results are much better.
I used bit thicker pads at the back and front.
I did 20 loop run of 3DMark stress test and GPU goes up to 76C and memory 80C but power remains steady and no thrm limit.
I think pads supplied with this block are not very good.
So overall temps are higher but now GPU seems to work ok
It looks like the pads supplied With the block are not very good and did not make proper contact.
 
A little update, I decided to give it another go with new pads/paste all around and results are much better.
I used bit thicker pads at the back and front.
I did 20 loop run of 3DMark stress test and GPU goes up to 76C and memory 80C but power remains steady and no thrm limit.
I think pads supplied with this block are not very good.
So overall temps are higher but now GPU seems to work ok
It looks like the pads supplied With the block are not very good and did not make proper contact.
Whats your fluid temp ? 76c is still too high. Those alphacool blocks do about 15c core/ fluid delta. Assuming you made proper contact fluid temp would be around 60c which doesn’t sound right.
 
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Not sure about fluid temperature tbh, don’t have anything measuring it.
It does seem a bit too high, I may have to re do it again with less paste.
So far it’s working fine and no crashes so it’s a big improvement
 
Not sure about fluid temperature tbh, don’t have anything measuring it.
It does seem a bit too high, I may have to re do it again with less paste.
So far it’s working fine and no crashes so it’s a big improvement
Too much paste wouldn't cause that, those core temps are worse than air. Definitely a contact issue.
 
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