PSU Size/Efficiency/Brand for a RadeonVII/3850x

Vish Petrol

Vish Petrol

Vish Petrol

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I've had an EVGA 850GS for the last 2 and a half years with a 7 year warranty and have been happy with it. I'm going to be giving it to my friend along with my old computer to my friend who needs one as I don't want to leave in the Antec earthwatts green PSU which I bought 6 years ago for £20 used off the bay.

Currently i'm running a ryzen 1700 at 3.9 and 1.4v and an overclocked radeon 7 at 100hz 3440x1440. When I am running Unigine heaven my power meter says that the system is drawing around 350w. When I start running furmark the system draw is around 400w. The highest recorded on the meter is 449w but I don't know when that happened, possibly when I was testing my radeon 7 at higher clocks as it could run higher clocks when I first got it in furmark and then crash in Heaven/GTA V/Shadow of the Tomb Raider.

I'm not too sure how much to spend which doesn't help, but when I saw there were EVGA/Seasonic PSU's with 12 year warranties I though that it would be worth investing in one. From what I can tell, the EVGA 12 warranty was only for a short period and now only offer a 10 year warranty again.

If the rumours are true, there will be 16 core, 32 thread chips out in a few months which could potentially be overclocked to 5 ghz, and looking at some reviews for the current gen threadripper chips, the potential power draw leaves me unsure what size PSU to look at.

https://www.overclock3d.net/reviews/cpu_mainboard/amd_threadripper_2950x_and_2990wx_review/21

https://bit-tech.net/reviews/tech/cpus/amd-ryzen-threadripper-2990wx-2950x-review/6/

The threadripper systems which are clocked at lower frequencies are drawing a lot of power in the reviews which makes me think that I may need a big PSU, but I dont know what to go for.

Originally I was looking at a Seasonic Prime Ultra 650 GOLD which I had seen for £105 but now that appears to be too small.

At a minimum it looks like I would need 750W, for which i've found a Seasonic Prime (non Ultra) 750w Platinum, which has better efficiency and the same 12 year warranty but is an older model for £130.

Then if I want some headroom it looks like i'm going to be spending £150 plus for which i've found

EVGA 850w T2 which is a titanium model for £160 but only comes with a 10 year warranty.

Seasonic Prime Ultra Gold 1000w for £170 with more headroom but less efficiency

Seasonic Prime (non Ultra 1300w) for £190 which is also an older model but still had the 12 year warranty and more capacity than i'll ever need.

The system would be for gaming and some photo editing. Possibly some video in the future but unlikely. 16 cores/32 threads is massive overkill at the moment and I could just get an 8 core or 12 zen 2 processor but I anticipate that there will be some benefit in the distant future in upgrading to the 16 core so I want this PSU purchase to be able to cover that.

I'm not sure what to go for. I know Antec is the same as Seasonic and made by Seasonic but when I look for reviews I find too many negative points. Is it worth investing in a more efficient PSU? According to the below review, the components in the Prime Gold series are the same as the higher end models, and the only difference is efficiency. Should I just go for the EVGA even with a shorter warranty and better efficiency?

https://www.hardocp.com/article/2017/08/23/seasonic_prime_1000w_gold_power_supply_review/9

I didn't link any PSU's because I found them on another site and I don't know if its allowed. Any advice or suggestions would be appreciated.

I probably average an hour of gaming and 2 hours of youtube a day. Would it pay off to purchase a higher efficiency PSU?
 
Hardware wise there's going to be little common between current AMD CPUs and Zen2 based.
Current ones are made on originally Samsung's phone/tablet CPU node.
Leading to crappy clocking and high power consumption increase for getting 4Ghz...

Zen2s are made on TSMC's 7nm High Performance node designed from the start to give good clock speeds.
We don't know final clocks etc yet, but in CES AMD demoed eight core engineering sample matching 9900K's processing power at ~50W lower power consumption.
So considering I/O die being responsible for part of power draw I would say TDPs in AdoredTV's rumours in December are very realistic.
Meaning 12c/24t likely drawing less than 9900K's actual power draw unless pushed.
Even 16c model could fit to that.
Currently AMD is more honest about TDP meaning max consumption while Intels grossly break their TDP when loaded unless BIOS is limited to marketing TDP.

Though in gaming you won't be needing 16 cores in long time and it's likely going to be pretty total waste of money.
All overpriced low core/thread count Intels are going to take care of that.

And even if games do start needing more cores than Intels have, there's going to be few primary threads setting limit for performance.
So unless you manage to get all core clocks to same level as automatic boosts, performance might just drop.
And with 16 cores there would be heck of time in trying to push all of them there.
AMD already has very complex and granular automatic boosting to clock high individual cores which are the best clocking on that CPU.
Time of manual clocking making sense is simply dropping farther and farther into past.
Unless you just want space heater.
 
Based on what you've said I guess I wouldn't need more than 750w and after doing more research the 2 i've narrowed it down to are:

Seasonic Focus Plus+ 750 Watt Gold Modular PSU/Power Supply for £89.99
10 year warranty

Seasonic 750 Watt Prime Fully Modular 80+ Platinum PSU/Power Supply £129.99
12 year warranty

Is it worth paying the extra for the extra efficiency and 2 year extra warranty? From the below page it seems that they are based on the same platform

http://www.jonnyguru.com/forums/sho...orm-for-their-new-lower-wattage-Prime-Ultra-s
 
750W is pretty much biggest size needed, unless you're going to have two high end graphics cards, or do very heavy space heater building/overclocking.
And if avoiding worst power hogging graphics cards, simply reaching 400W power draw in games would be lots of work with 650W leaving good reserve.

Games being bad at fully loading arbitrary high count of CPU cores means CPUs don't draw that high amount of power in them.
And Zen2 is going to have low power draw under say only four truly stressed cores load.
That all 8 cores/16 threads heavily loaded with Cinebench CES demo CPU had around 70-80W power consumption when power draw of system (likely including PSU losses) was fair 130W:
https://youtu.be/buQ_Qiacz8U?t=7m30s


Efficiency wise differences between 80+ Gold and Platinum are small.
There's never been that big difference between PSUs separated by single step and with higher efficiencies those get smaller.
Under gaming load power consumption difference would likely be ~8 - max 10 watts. (using SilentPCreview's measurements as base)

Though at very low loads like during idling (desktop/web surfing) that difference doesn't shrink linearly with absolute power draw and older designs lose efficiency faster.
Especially best 80+ Titaniums keep very high efficiency to very low loads.
Difference from Gold to Titanium would be in five watts class during PC idling, with 80+ Gold PSU heating itself with twice the power of 80+ Titanium.
But 80+ Titanium has that literal high end cost.

While no doubt having lots of common, Focus and Prime serie are built differently with Focus build to be very compact.
https://www.kitguru.net/components/...easonic-focus-plus-gold-fx-850w-psu-review/4/
https://www.kitguru.net/components/power-supplies/zardon/seasonic-prime-850w-gold-psu-review/4/
Prime serie has more component oversizing and less cost control like highly ribbed heatsink.
Along with including room for some literally up to twelve and half level oversizing in Titanium models:
650W Titanium has input/hold up capacitance usually found from 1kW level PSUs to almost double hold up time from that required by ATX specification.
(would keep going over 30ms power cut)
 
Prime has 150,000 hours MTTF, Focus has 100,000 hour MTTF.

It's as EsaT has said Prime is more over-engineered compared to the Focus, however Focus will still be very high quality.
 
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