Lower case fan speed having positive impact on GPU temps?

[MerchantBanker]

Ok, so since I follow Linus and his followers seem to be quite clued up I thought I'd join the forum because I want to gather some opinions/facts regarding case fan speed and airflow having an effect on GPU temps. 

Basically, I've been running my PC in a Car00GTXbide Air 540 for some time now and I've been using the corsair sp120 fans and a 140 in the exhaust. 
My GPU's are 2 gtx 780 reference design.

I have quite an extreme fan profile, I like my GPU to run as cool as possible so in game the fans are generally kicking at 90%. I don't mind the noise as I use a headset. Playing under full load in Far Cry 4 they tend to run at about 75-79c (bearing in mind I am running in Sli.)

I just added the little voltage reduction things onto my fans to see if there was a dramatic difference in performance and noise etc...  

SO now my fans are running at slower speeds and moving less air but my GPU's are still running at 90%, the odd thing is my temps under load are now considerably lower 55-73c.

I want to know why and if it is possible that high airflow can actually pull air away from the GPU fan enough to have a negative impact on thermal performance.



Cheers,

 

James

 

[Kyuubixchidori]

Ok, so since I follow Linus and his followers seem to be quite clued up I thought I'd join the forum because I want to gather some opinions/facts regarding case fan speed and airflow having an effect on GPU temps. 

Basically, I've been running my PC in a Car00GTXbide Air 540 for some time now and I've been using the corsair sp120 fans and a 140 in the exhaust. 

My GPU's are 2 gtx 780 reference design.

I have quite an extreme fan profile, I like my GPU to run as cool as possible so in game the fans are generally kicking at 90%. I don't mind the noise as I use a headset. Playing under full load in Far Cry 4 they tend to run at about 75-79c (bearing in mind I am running in Sli.)

I just added the little voltage reduction things onto my fans to see if there was a dramatic difference in performance and noise etc...  

SO now my fans are running at slower speeds and moving less air but my GPU's are still running at 90%, the odd thing is my temps under load are now considerably lower 55-73c.

I want to know why and if it is possible that high airflow can actually pull air away from the GPU fan enough to have a negative impact on thermal performance.

Cheers,

 

James

 

let games run for awhile. Let the case "heatsoak". like it may take up to a hour for the whole case to warm up. and once it fills up with hot air, The lower speed fans wont be able to take it out as fast. The best way to reduce temps is to undervolt your graphics cards. I have 7970s in crossfire, and they are a freaking furnace. My normal overclock when I had 1, was okay, but with both they get up to low 90s C. took them back to stock, and did a mild undervolt, and now they rarely break 65*C

[MerchantBanker]

Oh the temps don't bother me, I'm just curious as to why they're suddenly running much cooler when my case is theoretically less effectively cooled. 

[MerchantBanker]

You experience this phenomenon because your cards are using the reference blower design.

 

Because they do not discharge warm air inside the case, they do not benefit from the rear exhaust fan.

 

In fact the exhaust fan is working against your cards because they are also acting as exhaust fans.

 

I wouldn't be surprised if they get cooler if you totally block off the rear fan.

So having positive air pressure aids in the blower design set up. Makes sense.

It's interesting I'm actually quite interested to see what will happen if I unplug my exhaust fan now.