Question CPU hitting 95C - - - cooling fan upgrade ?

[shawnhalf]

Hi all... a few days ago I received a PC that I bought on eBay - a Dell Optiplex 7020 SFF Desktop PC 3.6GHz Core i7-4790 8GB DDR3 ram with no HDD. Upon receiving, I installed Win 7 Home Premium 64-bit and added another 8gb RAM and a 128GB SSD drive.

I got this machine to mainly run trading system backtests (lots of number crunching, lots of continuous hours use) so as soon as I got everything up and operational, I gave it a whirl. The CPU heated up to around 95C while doing a backtest and the fan was going like a jet engine... didn't sound too good. In the Windows Power Settings screen, I backed off the Max Processor Utilization from 100% to 99% and this dropped the CPU temp to around 89C/90C and quieted the fan down. Better, but still running pretty hot. Dropping the Max Processor Utilization % even more is an option, but this slows down the backtesting speed pretty significantly.

Ideally. I'd like to leave CPU usage at 100% and have a better cooling fan do the work of keeping the temps down. Would anyone be able to recommend a cost-effective cooling fan/heatsink for this PC that could do the job? I didn't pay a lot for this machine, so it really wouldn't make sense to pay a whole lot for a super-duper cooler... just something a little better than what's in there now (I'm assuming it's the stock Dell cooler) to bring the temp down a bit. This is my first experience with an "SFF" - there's not a lot of empty space inside the case, things are pretty crammed in there!


The full PC specs are:

- Win 7 Home Premium 64 bit
- Intel i7-4790 cpu
- Generic no-name el-cheapo 128gb SSD bought on temu.com
- 255W stock Dell PSU
- 16 gb DDR3 ram. 8gb already in there, added 1 8gb Corsair Vengeance stick.


Thank you everyone...
Shawn

 

[satrow]

First thing I'd check would be to reverse the case fan to see if it's fitted correctly, could make a difference. Unsure of the layout of that model but there may also be an alt. fan position.

 

[stonecarver]

My first thought is to redo the CPU's thermal paste. If it's the original paste 100% most likely hard and crusty. That model Dell came out in 2014.

That's where I would start.

 

[shawnhalf]

Thanks satrow & stonecarver.

Satrow - the case fan seems to be good... when I put a piece of paper against the case it sucks it in (instead of blowing it out). So it's drawing in air okay.

Stonecarver - I will check about the thermal paste. I've never fiddled with CPU manipulations like that nor applying new thermal paste, but I'll check some youtube videos on how to do it. I've actually got a little syringe of thermal paste here... it's not the best but if the existing paste is all hard and crusty, it ought to make an improvement. Any preliminary thoughts about a possible upgrade cooling fan/heatsink and estimated cost?

Cheers
Shawn

 

[stonecarver]

Honestly the Dell factory heatsink and fan actually do a acceptable job cooling. I would just take your time dismantling your cooler and also remove the fan to clean the underside.

Between the underside of the CPU fan and the top of the heat sink can get a layer of dust bunny blanket that is hard to see with a quick look with out removing the fan. Heck try that first and see how dirty or not that area is.

If you do get in there and there is a lot of dust use a paint brush to just loosen the dust than hit it with a blow dryer on cool. Keep your fan from spinning while your hitting it with blow dryer.

 

[satrow]

So it's drawing in air okay.

Reversing the fan might make a difference, very easy to do (and easy to get it the wrong way around during a big clean/rebuild) and it then exhausts the hot air which may give lower temps.

 

[shawnhalf]

Success guys! I applied a new coat of thermal paste (old stuff was almost all dried out and gone) and tried a backtest at 100% CPU power. Temps went down from 95C to about 88C-90C. Good improvement, but wait there's more! I had read online that there was a bios setting to have the fan go at full speed all the time, so I enabled that. Tried another backtest and wow, temps down to 73C-75C ! Little bit noisy but I don't care. I think I'm good with the stock Dell cooler... for now anyways. What do you think guys? Thank you so much for the assistance.

Cheers
Shawn

 

[BFG-9000]

You know one of the things I've noticed after working on many, many Dells over 30 years is their later BIOSes consistently seem to run the fan noticeably faster at idle. When Dells are new, they are nearly silent, and stay that way right until you go update the BIOS to a much newer one...

I don't know if they do this to compensate for drying paste or accumulating dust over time to reduce RMAs, their engineers decided the original cooling was actually insufficient for stability or lifespan, or to simply annoy you into buying a shiny new SFF or laptop from all the noise. But I'll bet even that isn't as loud as running the fan at full blast all of the time, so you might look to see if there is a newer BIOS available.

 

[kira-faye]

As long as you can live with the nose [noise ?] that will be fine, yes.

 

[shawnhalf]

You know one of the things I've noticed after working on many, many Dells over 30 years is their later BIOSes consistently seem to run the fan noticeably faster at idle. When Dells are new, they are nearly silent, and stay that way right until you go update the BIOS to a much newer one...

I don't know if they do this to compensate for drying paste or accumulating dust over time to reduce RMAs, their engineers decided the original cooling was actually insufficient for stability or lifespan, or to simply annoy you into buying a shiny new SFF or laptop from all the noise. But I'll bet even that isn't as loud as running the fan at full blast all of the time, so you might look to see if there is a newer BIOS available.

Thanks for the response BFG. Well, my top priority is to keep the CPU in this little SFF half-decently cool... I don't mind if the fan has to go like a 747 jumbo jet to do that! (the computer is in another room cranking away so the noise is not a problem).

Cheers
Shawn

 

[shawnhalf]

As long as you can live with the nose [noise ?] that will be fine, yes.

I can live with it!