Question NewEgg's calculator recommends 800~900 Watts but I've got a 750, do I really need to upgade?

Aug 26, 2022
8
1
15
0
I have a Mini ITX with the following specs:

MB: ASUS ROG STRIX Z590-I GAMING
CPU: Intel Core i9-11900
RAM: 2 * 32 GB DDR4 3200
Storage: Sabrent 1TB Rocket 4 PLUS NVMe 4.0
CPU fan: Noctua NH-D15S
Case fan: None (open concept case)
PSU: Corsair SF Series, SF750, 750 Watt, SFX, 80+ Platinum Certified

Now I'm hoping once the GPU prices settled, I'll buy a RTX 3090. But when I consult NewEgg's PSU calculator, it suggests 800 to 900 Watts. Do I really need to upgrade my PSU? How big of a risk is it if I don't?

And I forgot to mention, I'll use this setup for Machine Learning model training. This means long long hours of number chrunching with GPU (like weeks of running the machine at full speed).
 
Last edited:
Aug 26, 2022
8
1
15
0
What's the CPU usage in this usecase?
The processing will be mostly on the GPU but it does not mean that CPU will be ideal. To be honest, it's been a while since I've had such a setup and as I said in my post, I don't have the GPU yet so I cannot test it right now.
Having said that, I have lost a GPU once before. But that was a different setup. In fact, that's why I'm a bit hesitant. This is my old setup:

CPU: Intel Core i7-4790
RAM: 2 * 16 GB
GPU: EVGA GeForce GTX 1080 Ti FTW3 Gaming
PSU: EVGA SuperNOVA 750 G3, 80 Plus Gold 750W

What happened back then was that the GPU stopped working one day and I had to send it back to EVGA. They replaced it for me since it was still within the guarantee period (it gave up within the first year). I don't think that incident had anything to do with the PSU but still it made me cautious when it comes to dealing with expensive hardware.

I know I didn't really answer your question but that's only because I don't really have an answer.
 

cAllen

Distinguished
Jun 5, 2008
106
25
18,610
0
The 750 watt psu is not sufficient. While NE calculator confirmed 800-900, you want a 20% buffer for spikes and other variables...especially with a hard working gpu cruncher. I might suggest you consider going with an efficient 1200 watts PSU. YMMV
 
Last edited:
Reactions: Inthrutheoutdoor

Inthrutheoutdoor

Reputable
BANNED
Feb 17, 2019
255
66
4,790
6
psu's:

Go big or go home (and suffer the consequences if your system starts going poopoo due to insufficient powah ! )

But as already stated, with the intended use & parts you indicated, having a little extra powah available if needed would be betta, plus if you decide to upgrade later to a moar powahful machine, you won't have to buy anutha PSU at that time :D
 
For that use. I'd be leaning towards 1000 watts. To keep the load lower on the PSU.

That systems probably going to pull 600-650 watts under load (CPU + GPU). You really want more headroom between long term draw and rated capacity, not to mention power spikes. Running weeks at that load at a time. Would keep that PSU pretty toasty for a long time. I'd expect that to at least reduce its lifespan.

If it is too much. The most likely problem is the PSU overheating and cutting power to the computer. Which would be really unpleasant halfway through your number crunching task. It's got good safety features. But in any PSU overheat scenario. Even with the best of PSU. There is always the risk of a blow out. Taking your computer with it.

Bottom line. I just wouldn't want to risk a computer that expensive. Especially one doing actual work. Work that takes weeks to complete. Saving what? $150 to $250 but risking a few thousand in equipment and a bunch of time wasted. The risk to reward just isn't there for me.

If you think you'll add a second GPU. To increase your compute capabilities in the next couple years. Just bite the bullet now and get a 1300+W PSU.

Of course, get a good quality one like you've got now. If you are using a UPS. You'll also want a heavy duty one. Not the $100 junk meant for regular computers.
 
Aug 26, 2022
8
1
15
0
Any particular PSUs? I've been looking online in the past few minutes but so far, I could not find that many options. As a reminder, this is a MiniITX setup. So I believe my options are only SFX and SFX-L form factor (not sure though).

These are what I've found:

  1. Asus ROG Loki 1000W SFX-L
  2. Corsair SF1000L
  3. FSP Dagger Pro 1000
  4. Silverstone SX1000 Platinum
  5. Thermaltake Toughpower SFX 1000
  6. Cooler Master V1100 SFX Platinum
  7. Cooler Master V1100 SFX-L Platinum
  8. Asus ROG Loki 1200W SFX-L
  9. Cooler Master V1300 SFX Platinum
  10. Cooler Master V1300 SFX-L Platinum
But the problem is that out of all the PSUs listed above, it seems only the Silveratone's SX1000 is out and the rest are under development.
 
Aug 26, 2022
8
1
15
0
But this an open concept case...so why are you limited to SFX and SFX-L? Picture might help.
Not sure if "open concept" is the correct term for it. This is my case:

https://www.hydra-shop.com/product-page/hydra-mini

Even though I could ignore the fact that a bigger PSU could simply go beyond the case's boundary, I prefer something that actually fits. Also, I went with Mini ITX because I wanted something small and light. I don't have much room and if I have to relocate, a Mini ITX is more feasible to drag with me.
 

Phaaze88

Titan
Ambassador
View: https://www.youtube.com/watch?v=wnRyyCsuHFQ


^Something to consider.
Steve mentions that Small Form Factor power supplies stand to get shafted the most from a card of that caliber, due to their smaller 'real estate' and the 40-series is rumored to be even worse with it's transients.
Those power supplies in development that you've listed are likely related, with those rumors being true.

SID probably asked about cpu utility in relation to the transients. If a 3090 can do 600+ watts transients by itself, how much does the cpu add to the load?
Granted, power supplies can temporarily handle bursts a little above what they're rated for, but that part is lost on me.
 

cAllen

Distinguished
Jun 5, 2008
106
25
18,610
0
All Due Respects...because I hate people telling me what to do "unsolicited", but you already said you were going to throw an "RTX 3090" on this minimalist "frame"...which is why you need the "larger" PSU. A regroup might be in order. YMMV.

Can you show us a picture of your actual rig as it stands now...including the D15S?
 
Last edited:
Aug 26, 2022
8
1
15
0
Sure, I don't mind. Here you go:



I've got a NH-L9i too but that does not really cool it properly. It works but it throttles so fast.
 
Aug 26, 2022
8
1
15
0
Thanks for the recommendation. I'm not going to buy a GPU right now. I'm not in a rush. I would rather wait for the 40 series to come out so 30 series will be cheaper. But still, it has to be 3090 or 3090 ti. It's not a matter of speed for my use case. But rather memory size. In ML, more memory means larger batch size which translates into higher parallelization and in turn faster training.
 
Reactions: logainofhades
Aug 26, 2022
8
1
15
0
I know this is not directly relevant to this post but in case someone finds it useful, here are the thermals of my system using two different fans:



 
Aug 26, 2022
8
1
15
0
Progress was made, so I thought I should share it here. I got a Watt meter to measure how much power my machine was drawing. Running a stress test that puts all the 16 cores of my CPU under load draws 223W (max). That leaves 750W-223W = 527W for the GPU. Now, is that enough for a 3090? That I need to do more research.
 

cAllen

Distinguished
Jun 5, 2008
106
25
18,610
0
With the high end 30 Series NVDIA you have to figure for spikes. Gamers Nexus was a good video. I would add in X1.5-2 GPU maximum draw. I am "not" the expert here, but if this was my rig I would go 1000-1200 watt platinum. YMMV
 
Last edited:

Vic 40

Titan
Ambassador
Thought about just trying? The SF 750 watt psu is a very good one and if something goes wrong it likley just shuts down because one of the protection features kicked in.

A review about it here by Aris,
https://www.tomshardware.com/reviews/corsair-sf750-psu,5979-3.html

The unit can deliver almost 970W of power, before it shuts down because of the over power protection's triggering. Those are lots of Watts, but OPP is still set below 130% of the unit's max-power-output so it is ideally configured.
seems it can take a hit. As i said if something goes wrong is it likely that this or another protection will keep you safe. Is in the end up to you. If you're really worried get something more powerfull.
 
Reactions: MehranZ

ASK THE COMMUNITY

TRENDING THREADS