Storage HDD sat on PSU?

[nedge2k]

I built a custom HTPC into a Marantz CD player. The initial build was with a quiet 250w Flex ATX PSU (80x40x180mm). Then I fitted a low profile GTX 750ti and upgraded to a 400w 1U PSU (100x40x235mm). However, despite claiming to have thermal fan control, it's like a jet engine at all times.

There are a few 1U PSUs I could replace it with BUT the ones I want are generally not available to the consumer market.

So, what I'm considering is an SFX or SFX-L PSU. The problem is, the 3.5" HDD must be mounted above the PSU. Currently, with the 1U PSU, I have an air gap between the PSU and HDD of around 20mm. I have around 90mm of space (vertically) in the case, an SFX PSU is 63mm high and a 3.5" drive is 26mm.

Ideally i'll be using a Gold/Platinum/Titanium SFX-L PSU so it generates as little heat as possible.

Question is, would having the HDD sat directly on the PSU (possibly separated by 1mm aluminium plate/bracket) have a detrimental effect (heat/vibration/EMI)? It likely would have little to no space above the HDD also.

TIA

 

[jeshikat]

Unless the fan is defective in the PSU, vibration shouldn't be much of a concern. EMI shouldn't be an issue either since both are enclosed in metal.

Heat is trickier to say, but you're not drawing that much wattage so if you use the SX500-LG V2.0 there shouldn't be much heat buildup in the PSU since it has an always-on fan.

 

[nedge2k]

Well, those were my thoughts also tbh, although I was planning on using the SilverStone SX800-LTI as a belt and braces approach. Plus it would future proof me should any decent low-profile cards come out. I know a low profile GTX 1050 was announced recently so hopefully other stuff will follow!

Cheers

 

[jeshikat]

Well, getting a 800W Titanium-rated unit is definitely one way of addressing the heat issue

 

[nedge2k]

Go big or go home

 

[confusis]

I've run drives in hotter locations (directly above CPU heatsinks), I think you'll be ok at these wattages

 

[ChainedHope]

You're fine on the heat topic. Before I tore down my acorn build, I had an ssd duct-taped to the top of a SX600-G. It got a bit toasty (ventilation went over and around the SSD) but was within operating range under heavy load.

 

[nedge2k]

You're fine on the heat topic. Before I tore down my acorn build, I had an ssd duct-taped to the top of a SX600-G. It got a bit toasty (ventilation went over and around the SSD) but was within operating range under heavy load.

I'm talking HDD, not SSD. If it were an SSD I wouldn't be worried!

 

[nedge2k]

I think i've come to a compromise. From back the front I have approx. 280mm. So i'm going to try an SFX (100mm) PSU and lay the HDD (150mm) on the floor of the case in front of it. It'll be a bit tight (cable wise) and the SFX might be a bit louder than an SFX-L but I think it's prolly the safest option!

 

[ChainedHope]

I'm talking HDD, not SSD. If it were an SSD I wouldn't be worried!

Edit - Was a bit tired and out of it (had been up for close to 30 hours at that point) so I was the one who ended up being rude with my response and for that im going to apologize to @nedge2k , I'm keeping the reply but throwing it in spoiler tags if someone wants the math. I did show that the HDD should operate between 25-55C, with the better drives being in the 25-40C mark (no matter if they are 2.5'' or 3.5'') which is still under the temps of the google research paper that was linked in the below comment.

Again sorry for my rant/outburst, but I took the reply a bit differently than intended in my dazed state.

I did read that you were using an HDD btw, and I had done the math shortly before I made my original reply. Honestly figured a simple "dont worry about it, ive done worse" was enough to suffice so thats why I gave an example with one of my worst-case scenarios that ive done.

Spoiler

No need to be rude. Lets do a bit of math shall we? Im going to assume conditions for everything, you change the numbers accordingly.

Lets assume your ambient temp is around ~22C (thats what mine was when I did temp testing on my build).
And lets pull some data from a few spec sheets to go off of.
HDD - Operating range is 0 to 60C.
SDD - Operating range is 0 to 95C.
Operating range is the actual temperature in the HDD, not the temp of the outside of the hard drive.

The PSU i used was a SX600-G. In the case, my SSD would reach 55C at full load with the SSD covering up 1/3rd of the ventilation holes on one side with duct tape. So pretty much no airflow and direct heat transfer from the PSU. Outside of the case it averaged at 34C. The delta is ~21C (give or take 1-2C for error). So lets go with the higher error. Lets say the delta is ~23C just from shoving it on top of the PSU. This gives an actual delta of ~35C from ambient temps.

Now then, from my testing a 2.5'' drive gets hotter than a 3.5''. So we are going to use a 2.5'' drive as an example. They have less surface area and less chance for heat exchange. 2.5'' drives will normally run at around 20-35C in a well ventilated area with a ~20C ambient. Well you are killing that ventilated area, so lets assume that the situation is as bad as mine was. And lets use the highest numbers for a giggle. This is going to bring you to around 55-70C. Which for a good HDD would be in the 55-60C area.

Now heres the fun part. You will not be pushing 650w on a 600w psu like I was. You originally said that you were going to use a 250W psu. This is more than enough for any CPU + 1050. Now you want to use a larger SFX-L psu which if memory serves me correct, the good SFX-L PSUs are 500-800W. You are going to be using 50% or less of the PSU in this situation which means that the PSU will not get as hot. Actually most PSUs can passively cool at that rate or with very limited RPM on the fan. This means that your PSU will not be giving you a delta of ~23C like mine on your HDD.

So all that math? pretty much useless. You arent going to see more than a ~5-10C difference on the outside of the HDD which would only be around a ~2-6C difference on the inside of the HDD. Which now brings your HDD to being around 25-55C. And if you go 3.5'' its brought down even further because there is more surface area for the heat exchange.

*note - Im a bit tired, might have messed up some math at some point, but the logic holds

 

[nedge2k]

No need to be rude.

I wasn't being rude, I was merely pointing out that you hadn't bothered to read my post as the distinction between a HDD and an SSD is quite significant. I mean, the title kinda gives it away, no?

An SSD will happily run hotter and it'll run hotter because it's solid state and, unlike a HDD, it doesn't have a metal case to dissipate the heat (in most cases).

Google published a paper on HDD temps vs failure rates, the tldr; version is here: http://www.buildcomputers.net/hdd-temperature.html but in short, anything over 45°C leads to higher HDD failure rates.

Currently, in my case - with it's single 80mm exhaust fan and the HDD mounted above a 1U server PSU, with the fans at full speed seemingly constantly and a ~20mm air gap between them - the (5200RPM ECO) HDD sits at 42°C when gaming.

I was going to risk it until I had another look at my case last night and did some measuring but I think I can get away with having an 100mm SFX and HDD mounted on the floor of the case - something I should have done originally instead of keeping the 250w Flex PSU and then upgrading it to the 400w 1U when I got the GTX 750ti because of how I ended up mounting the HDD. If your assumption of 2-6°C is correct, that's puts me in the danger zone when gaming and i'd rather have as much headroom/reliability as possible as it's our main and now only source of TV/Film/Gaming.

 

[nedge2k]

Edit - Was a bit tired and out of it (had been up for close to 30 hours at that point) so I was the one who ended up being rude with my response and for that im going to apologize to @nedge2k , I'm keeping the reply but throwing it in spoiler tags if someone wants the math. I did show that the HDD should operate between 25-55C, with the better drives being in the 25-40C mark (no matter if they are 2.5'' or 3.5'') which is still under the temps of the google research paper that was linked in the below comment.

Again sorry for my rant/outburst, but I took the reply a bit differently than intended in my dazed state.

We've all been there

Out of interest, you mentioned drawing more power from a PSU than it's rated for - is this something you do regularly? If so, how well to PSUs hold up to that these days?

Now heat isn't as much of an issue, i'm considering a 450w PSU instead - which should be fine up to a GTX 1080 (if one ever comes out in LP) but if something more came out in LP form, like the Titan X (unlikely I know), which would require about 500w - how safe would it be before things went titsup? Only talking 1080p gaming also, not switching to 4k for a few years yet.

 

[ChainedHope]

We've all been there

Out of interest, you mentioned drawing more power from a PSU than it's rated for - is this something you do regularly? If so, how well to PSUs hold up to that these days?

Now heat isn't as much of an issue, i'm considering a 450w PSU instead - which should be fine up to a GTX 1080 (if one ever comes out in LP) but if something more came out in LP form, like the Titan X (unlikely I know), which would require about 500w - how safe would it be before things went titsup? Only talking 1080p gaming also, not switching to 4k for a few years yet.

Its not recommended but you definitely can do it for short bursts of time. Because of the overclock on both my CPU and dual Nanos, It would go over the rated wattage. All in all it handled it fine for a few hours at a time, but I wouldnt ever put it under 24hr load testing. The longest session I had was when I streamed for 24hrs for a charity event, but I wasnt playing the most demanding games.

 

[nedge2k]

Good enough for me. Corsair SF450 ordered. Cheers

 

[nedge2k]

...and here's how she fits:

https://smallformfactor.net/forum/threads/marantz-cd5005-gaming-htpc-case.1494/