300w psu enough for this build?

nycalex

Average Stuffer
Original poster
Nov 6, 2018
77
35
planning my next semi-budget SFF build.

will go in a velka 3 case.

so i was able to buy a seasonic SSP-300SUG. it's a Flex atx psu with 300 watts and rated Gold.

was wondering if this would be enough to power this build:

Ryzen 1700 or 2600 or any other ryzen 5/7 with a tdp of 65w
16gb ram 2 x 8
1 x nvme drive
gigabyte gtx 1070 mini (single fan model)

does motherboard even matter as far as power draw? i have not procured a mini itx mobo yet, but most likely will be either asrock b450i or asus strix b450i

i'm planning to run whatever cpu i get undervolted at around 1.275v to 1.3v, last 3 x r7 1700 i had were able to do 3.8ghz @ 1.275, i'd be very happy to continue this.

GPU will be undervolted to 0.975mv or maybe i'll go down to 0.950mv, clocks i'd most likely set at 1800 with this undervolt.
 

wertigon

Trash Compacter
Sep 13, 2019
54
33
I assume this is the card you had in mind?


In short, not very likely. Power distribution will look something like this:

Motherboard: 10W-15W
Drives: 5W per drive
Fans: 2.5W per fan
CPU: Up to 160W, depending on load - best sweet spot buy is the 3600

This leaves ~100W for the GPU, which seems to draw at most 155W. With undervolting this will give you perhaps a 40W system wide reduction, which is just above the threshold unfortunately. 400W would've been fine.

Perhaps a better option is to put a 3400G in the build and put the money difference towards an x570 and an upgrade to a 4600G coming out next year?
 

nycalex

Average Stuffer
Original poster
Nov 6, 2018
77
35
I assume this is the card you had in mind?


In short, not very likely. Power distribution will look something like this:

Motherboard: 10W-15W
Drives: 5W per drive
Fans: 2.5W per fan
CPU: Up to 160W, depending on load - best sweet spot buy is the 3600

This leaves ~100W for the GPU, which seems to draw at most 155W. With undervolting this will give you perhaps a 40W system wide reduction, which is just above the threshold unfortunately. 400W would've been fine.

Perhaps a better option is to put a 3400G in the build and put the money difference towards an x570 and an upgrade to a 4600G coming out next year?

Thanks for the reply.

i got a second hand gigabyte 1070 mini from a egpu enclosure and i'm planning to build a SFF system around it. Chosed the velka 3 to take advantage of the short GPU and try and minimize the size as much as possible so that it fits in my tv cabinet.
i'm planning to set the cpu at around 1.275v and run all cores @ 3.6 or so.
As for the gpu, i'll be undervollting to anywhere between 0.865mv to 0.950mv and run it at around 1700~1800mhz depending on stability.

i'm just guestimating that a 300w gold seasonic flex psu can perhaps barelly handle this if i lower the voltages of both cpu adn gpu a bit.

My challenge on the flex psu is price. i can purchase a seasonic 300w gold rated flex psu for around $38. a step above this is reaching $89.99, which would be 400w.

Trying to see if i could squeeze this system on the 300w psu as i'm trying to lower costs as much as possible.
 

wertigon

Trash Compacter
Sep 13, 2019
54
33
Looking up some more figures, this seems more likely now;

Ryzen Gen 1 power draw
Ryzen Gen 2 power draw
Ryzen Gen 3 power draw

Especially a 3600 should draw a mere 70W or so, but even the 3700X only draws 90W at max load... Wow. The 3600 is the best price+performance / W right now, but I can understand if $200 is a bit steep for ya.

So CPU 70W, GPU 155W, you are left with 75W for everything else. Yeah, the 300W is doable in that case, not even a need to undervolt.