# 8+8 pin cpu pwr motherboard, but the psu has only 1 4+4 pin?



## PeterX9 (Jul 14, 2020)

I have an older FSP Gold S 750W psu that has 1 4+4 cpu pwr header, but some z490 motherboards have 8+8 pwr header, will it work (at least at stock settings), or should i just buy a new one since it wont even boot up?


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## agent_x007 (Jul 14, 2020)

Unless LN2, you should be fine with one.


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## maxfly (Jul 14, 2020)

No itll boot. Just connect the 4+4 to a 8 and itll work(make sure the pins all match). The only real reason there are 2 8s is if you were doing some hardcore sub ambient ocing. Youll be fine if you oc with air or watercooling.
Altho if your current psu is 8-10 yo it may be a good idea to upgrade.


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## PeterX9 (Jul 14, 2020)

maxfly said:


> No itll boot. Just connect the 4+4 to a 8 and itll work(make sure the pins all match). The only real reason there are 2 8s is if you were doing some hardcore sub ambient ocing. Youll be fine if you oc with air or watercooling.
> Altho if your current psu is 8-10 yo it may be a good idea to upgrade.


Thanks, its a good idea its "only" 7 years old, but yeah maybe this year i get a new one.


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## Vya Domus (Jul 14, 2020)

What board is that 8+8 is pretty damn uncommon and usually reserved for stuff like X299 or X399, I'd be concerned about that actually.


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## kayjay010101 (Jul 14, 2020)

Vya Domus said:


> What board is that 8+8 is pretty damn uncommon and usually reserved for stuff like X299 or X399, I'd be concerned about that actually.


OP mentioned it's a Z490 board, and there are a few ones that do use 8+8 instead of the usual 8+4, like the flagships. MEG Godlike and Auros Z490 Extreme, for example.


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## PeterX9 (Jul 14, 2020)

To clarify, I was considering the MSI z490 Unify (However the z490 tomahawk also has 8+4 pwr pin)


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## phill (Jul 14, 2020)

Personally If there's two power connections, I'd use them.  If your looking at a higher end motherboard with those sorts of connections, make sure you have a PSU that will supply those connections.

A mate and I did a test on an X99 SOC board, the noise that came from the VRMs when running at stock was quite noticable but it did as everyone said, worked fine.  I think we ran a few tests on CB or XTU (which I never recommend...)   When we connected the second connection, the noise went away.

I have some Z77 and Z97 motherboards with dual 8 pin configurations for the CPU, I always connect them up.  Yes it won't make masses of difference if you only use one and your not pushing the overclocks or power draw through the socket, but if there's two connections on the board, use them.  If your PSU doesn't support it, upgrade it.  You won't need a 2000w PSU, 650W to 850W is fine depending on what else you have in the system, but I'd definitely recommend a PSU upgrade.

What are your current system specs just so we can advise you a little more 'exact'?


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## PeterX9 (Jul 14, 2020)

Yes, I see its a" better" to have them plugged in however I never need more than 8 before. 
I am getting a 10700k with either a z490 unify or a z490 tomahawk (both of them are in a very good price range here), rtx 2070 super, 6x samsung 860 ssd, 1x 970 evo plus, Dark rock pro 4 and a Thermaltake j22 case with a total of 5 fans.


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## kayjay010101 (Jul 14, 2020)

PeterX9 said:


> Yes, I see its a" better" to have them plugged in however I never need more than 8 before.
> I am getting a 10700k with either a z490 unify or a z490 tomahawk (both of them are in a very good price range here), rtx 2070 super, 6x samsung 860 ssd, 1x 970 evo plus, Dark rock pro 4 and a Thermaltake j22 case with a total of 5 fans.



Just to clarify a bit here, the second connector will do pretty much nothing for a 10700K. The 8pin EPS connector is able to supply 235W if it's the bad type. Upto 350W (IIRC) if it's the better type. The 10700K peaks at ~190W as far as I could find on Google. The PL2 limit is even 229W so you'll hit that before you ever hit an actual power restraint in which case the second connector would actually be used. So unless you raise PL2 manually, there's no way for the chip to ever draw close to the maximum for a single 8pin connector, and if you do raise it, it still might not be able to do it without some serious cooling. 

That being said, if you're getting as expensive components as all that, I'd spend another $100-150 on a decent PSU just to be safe, as if the PSU is that old, I wouldn't really trust it not to fail and take your expensive components with it.



phill said:


> Personally If there's two power connections, I'd use them.  If your looking at a higher end motherboard with those sorts of connections, make sure you have a PSU that will supply those connections.
> 
> A mate and I did a test on an X99 SOC board, the noise that came from the VRMs when running at stock was quite noticable but it did as everyone said, worked fine.  I think we ran a few tests on CB or XTU (which I never recommend...)   When we connected the second connection, the noise went away.
> 
> ...



That sounds like a defective VRM to me. I've never had any noise from a VRM before, and I've never used more than a single 8pin, including on my older X99 board.


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## PeterX9 (Jul 14, 2020)

kayjay010101 said:


> Just to clarify a bit here, the second connector will do pretty much nothing for a 10700K. The 8pin EPS connector is able to supply 235W if it's the bad type. Upto 350W (IIRC) if it's the better type. The 10700K peaks at ~190W as far as I could find on Google. The PL2 limit is even 229W so you'll hit that before you ever hit an actual power restraint in which case the second connector would actually be used. So unless you raise PL2 manually, there's no way for the chip to ever draw close to the maximum for a single 8pin connector, and if you do raise it, it still might not be able to do it without some serious cooling.
> 
> That being said, if you're getting as expensive components as all that, I'd spend another $100-150 on a decent PSU just to be safe, as if the PSU is that old, I wouldn't really trust it not to fail and take your expensive components with it.
> 
> ...


Can you recommend a "2020" (preferably silent) PSU for around 100-150? The corsair hxi series are about 230 USD in my currency here, so they are off the table, and sadly FSP doesn't have any 500+ PSU too.


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## kayjay010101 (Jul 14, 2020)

PeterX9 said:


> Can you recommend a "2020" PSU for around 100-150? The corsair hxi series are about 230 USD in my currency here, so they are off the table, and sadly FSP doesn't have any 500+ PSU too.


Corsair's  RMx line is good. Something like the RM750x, maybe? I have one in my server currently and a 650W model that's been in my dad's PC for a couple years with 0 issues. I know PSUs were in short supply when Covid first hit though so I'm not sure if availability is great yet, which might be why you're seeing inflated prices.


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## PeterX9 (Jul 14, 2020)

kayjay010101 said:


> Corsair's  RMx line is good. Something like the RM750x, maybe? I have one in my server currently and a 650W model that's been in my dad's PC for a couple years with 0 issues. I know PSUs were in short supply when Covid first hit though so I'm not sure if availability is great yet, which might be why you're seeing inflated prices.


Sadly the RMx have the same price as the HX line (about 5-10 USD less), bequiet also have similar prices due to the situation.


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## phill (Jul 14, 2020)

kayjay010101 said:


> That sounds like a defective VRM to me. I've never had any noise from a VRM before, and I've never used more than a single 8pin, including on my older X99 board.


I'd hope not, it was a brand new board at the time   Just an experience that I have always remembered.  Besides, if you can buy brand new kit, why not re-fresh the PSU?  It can always be used for something else if not required right this second.
Never skimp on PSUs, a good one will and can save your system.


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## PeterX9 (Jul 14, 2020)

phill said:


> I'd hope not, it was a brand new board at the time   Just an experience that I have always remembered.  Besides, if you can buy brand new kit, why not re-fresh the PSU?  It can always be used for something else if not required right this second.
> Never skimp on PSUs, a good one will and can save your system.


I didn't want to skimp on it however, its been working great, (and my other pcs too, powered by the lower quality fsp hexa 500w) and before this fsp unit I had 2 doa corsairs so I thought I was lucky with this unit.


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## kayjay010101 (Jul 14, 2020)

PeterX9 said:


> Sadly the RMx have the same price as the HX line (about 5-10 USD less), bequiet also have similar prices due to the situation.


Ah, that's too bad then. You could get by with your current PSU and maybe wait until prices deflate again to normal levels. I do urge you to change it though when you can.



phill said:


> I'd hope not, it was a brand new board at the time   Just an experience that I have always remembered.  Besides, if you can buy brand new kit, why not re-fresh the PSU?  It can always be used for something else if not required right this second.
> Never skimp on PSUs, a good one will and can save your system.


I don't disagree with that, I always say the PSU is the most important part of any PC, moreso than any CPU or GPU. If it's the part you decide to cheap out on, it'll just be more expensive to replace your dead components.


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## arbiter (Jul 14, 2020)

Check the MB manual as likely tell you which one to plug in to for it to work properly. The 2nd 8 pin is likely for OC reasons more then anything.


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## phill (Jul 14, 2020)

PeterX9 said:


> I didn't want to skimp on it however, its been working great, (and my other pcs too, powered by the lower quality fsp hexa 500w) and before this fsp unit I had 2 doa corsairs so I thought I was lucky with this unit.





kayjay010101 said:


> I don't disagree with that, I always say the PSU is the most important part of any PC, moreso than any CPU or GPU. If it's the part you decide to cheap out on, it'll just be more expensive to replace your dead components.


I've seen so many people on the forum and with friends as well trying to skimp on PSUs, they aren't cheap considering what you will fork out for a CPU or GPU..  Spend a little more, get something much better...

Personally, EVGA G+ series are decent enough.  I have 4 or so of them, 650w and 850w models.  One of those are more than enough.  Gold rated and 12 year warranty (when I bought mine) and I wouldn't suggest them if they are a decent unit.  Obviously anything in the top tier of PSUs is a solid buy.  Seasonic, Super Flower etc. any of these would be a worth buy.


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## PeterX9 (Jul 14, 2020)

phill said:


> I've seen so many people on the forum and with friends as well trying to skimp on PSUs, they aren't cheap considering what you will fork out for a CPU or GPU..  Spend a little more, get something much better...
> 
> Personally, EVGA G+ series are decent enough.  I have 4 or so of them, 650w and 850w models.  One of those are more than enough.  Gold rated and 12 year warranty (when I bought mine) and I wouldn't suggest them if they are a decent unit.  Obviously anything in the top tier of PSUs is a solid buy.  Seasonic, Super Flower etc. any of these would be a worth buy.


Sadly the 650 is the only available model (evga is very rare in eastern Europe), however most watt calculator calculated my PC  around 680-780 watt, so I'm not sure the 650 would be a sufficient.


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## kayjay010101 (Jul 14, 2020)

PeterX9 said:


> Sadly the 650 is the only available model (evga is very rare in eastern Europe), however most watt calculator calculated my PC  around 680-780 watt, so I'm not sure the 650 would be a sufficient.


Uh, I don't know what calculator you're using but it's pretty wrong if it says 680-780W. The 2070S is about 215W, 280W at most. The 10700K is about 200W at most, the rest is pretty negligible so the overall consumption shouldn't be more than 500-550W. 650W should be just fine. My 2080 Ti watercooled build is running on a 750W EVGA PSU (G2 Supernova) and I've never seen the GPU go over 125% TDP (250 x 1.25 = 313W) and the CPU is usually around 120W, so total is usually around 450-500W. 
An easy way to find out how much your GPU could ever draw is to look at the power limit. The highest power limit on the 2000 series NVIDIA cards is 130% (IIRC there's one with 150% but that's not common) so take TDP x power limit to get the absolute highest it would be allowed to draw. So for the 2070S the TDP is 215, x 130% (1.3) we get 280W. With CPU at 200W, that's 480W. Add in about 100W of headroom, we get 580W. So 650W should be plenty.


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## EarthDog (Jul 14, 2020)

PeterX9 said:


> I have an older FSP Gold S 750W psu that has 1 4+4 cpu pwr header, but some z490 motherboards have 8+8 pwr header, will it work (at least at stock settings), or should i just buy a new one since it wont even boot up?


Of course it will work. The second 4/8 pin is optional. See any manual for z490.



kayjay010101 said:


> OP mentioned it's a Z490 board, and there are a few ones that do use 8+8 instead of the usual 8+4, like the flagships. MEG Godlike and Auros Z490 Extreme, for example.


Several do. No cause for concern as someone else blathered about.



kayjay010101 said:


> So 650W should be plenty.


Indeed it is in his case. Id be surprised if that system fully overclocked pulled 475W. 650W is plenty assuming it has all the connectors you


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## PeterX9 (Jul 14, 2020)

If an evga g1+ 650w and a fractaldesign ion+ 760p is at nearly the same price, which would be better? (never used evga or fractal design).


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## Assimilator (Jul 14, 2020)

Would help if you could provide a link to your PSU. A 750W should have dual 8-pin EPS connectors anyway. But you absolutely will not need the extra connector unless you are running a 10900K AND pushing the power limits to extreme values.



PeterX9 said:


> If an evga g1+ 650w and a fractaldesign ion+ 760p is at nearly the same price, which would be better? (never used evga or fractal design).



Fractal is higher efficiency and 110W more output, no question it's the better choice. Reviewed right here: https://www.techpowerup.com/review/fractal-design-ion-plus-series-760-w/


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## phill (Jul 14, 2020)

PeterX9 said:


> Sadly the 650 is the only available model (evga is very rare in eastern Europe), however most watt calculator calculated my PC  around 680-780 watt, so I'm not sure the 650 would be a sufficient.


If your concerned about which PSUs to buy, feel free to put up a screen grab for the items you can get, we can always weigh on what we think is better or best or worse


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## PeterX9 (Jul 14, 2020)

phill said:


> If your concerned about which PSUs to buy, feel free to put up a screen grab for the items you can get, we can always weigh on what we think is better or best or worse


Thank you, so I have the following PSUs in range: Fractal Design 760p ION+ (about 200 USD), Seasonic focus plus gold 750w (about 180USD), EVGA G1+ 650W (about 150 USD), Cooler Master MWE Gold 750 (180 USD)


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## phill (Jul 15, 2020)

I couldn't find a review on the Fractal PSU from JohnnyGuru, I do believe TPU had done a review on it which was very good, so I would say that the going by the TPU review, the Fractal PSU would be the one I'd consider most.  I can only go by what I use and the EVGA G+ has been great for me, but if it's a little too close to the maximum power for you, then I'd say the Fractal unit is the next best thing there 

I couldn't see many good reviews about the Seasonic unit but I think there's a few lower quality/priced units out there, which I'm not sure is what you'd be after.  I'm unsure on the Cooler Master unit as well..  I'd stay clear of that one


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## Mr.Scott (Jul 15, 2020)

The Seasonic Focus units are very good units.


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## kayjay010101 (Jul 15, 2020)

phill said:


> I couldn't find a review on the Fractal PSU from JohnnyGuru, I do believe TPU had done a review on it which was very good, so I would say that the going by the TPU review, the Fractal PSU would be the one I'd consider most.  I can only go by what I use and the EVGA G+ has been great for me, but if it's a little too close to the maximum power for you, then I'd say the Fractal unit is the next best thing there
> 
> I couldn't see many good reviews about the Seasonic unit but I think there's a few lower quality/priced units out there, which I'm not sure is what you'd be after.  I'm unsure on the Cooler Master unit as well..  I'd stay clear of that one


The Seasonic unit seems to be decent from reading reviews online, and JonnyGuru gave it a 9.6/10. That EVGA G1+ specifically (the G2 and G3 line is good) is actually not that good. It seems to be overpriced and has terrible transient response according to the reviews I found online. The cooler master unit is the same price as the seasonic unit, so I wouldn't bother. The last unit is also $20 more so it's not worth considering over the Seasonic unit.

It seems clear to me that the Seasonic PSU is the most sound choice of the four.


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## phill (Jul 15, 2020)

kayjay010101 said:


> The Seasonic unit seems to be decent from reading reviews online, and JonnyGuru gave it a 9.6/10. That EVGA G1+ specifically (the G2 and G3 line is good) is actually not that good. It seems to be overpriced and has terrible transient response according to the reviews I found online. The cooler master unit is the same price as the seasonic unit, so I wouldn't bother. The last unit is also $20 more so it's not worth considering over the Seasonic unit.
> 
> It seems clear to me that the Seasonic PSU is the most sound choice of the four.


Maybe it's just me being picky, but the Seasonic unit in the review was an FX..?  I was going with the assumption that the OP didn't mention the FX.. lol  But as mentioned before, most Seasonic units are very good units  
The reason I have the G+ units from EVGA was the price, when I bought them, they where something like £50 and £60 I think, half price basically!  I don't think I could have done better at that price point... 

Sounds like @PeterX9 has the nod from everyone for the Seasonic unit


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## PeterX9 (Jul 15, 2020)

Thank you all for your kind help.
I am now deciding between the Seasonic Focus plus gold 750W (SSR-750FX) and between the bequiet(ION+ 760p) since the TPU review mentions it one of the most silent psu (about 16 dbi avg noise), the place that has them on stock has only 15 USD difference between them (the Seasonic is the cheaper). I found a tomshw review about the seasonic that mentions it is noise under loads, so I am not sure yet.


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## phill (Jul 15, 2020)

Unless you live in a place where there's no noise, I don't think you'd ever notice any differences   I can't say I have really hear any of my PSU fans (my 1200w EVGA P2 is a little noisy at times) but I only notice it when there's nothing going on around me.  If the house is dead quiet, I just think, ah, louder music required 

@Mr.Scott Do you use the Seasonic units for your benching?


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## EarthDog (Jul 15, 2020)

PeterX9 said:


> Thank you all for your kind help.
> I am now deciding between the Seasonic Focus plus gold 750W (SSR-750FX) and between the bequiet(ION+ 760p) since the TPU review mentions it one of the most silent psu (about 16 dbi avg noise), the place that has them on stock has only 15 USD difference between them (the Seasonic is the cheaper). I found a tomshw review about the seasonic that mentions it is noise under loads, so I am not sure yet.


At this point, you are really in the minutia. You can't go wrong with either. 


phill said:


> Unless you live in a place where there's no noise, I don't think you'd ever notice any differences   I can't say I have really hear any of my PSU fans (my 1200w EVGA P2 is a little noisy at times) but I only notice it when there's nothing going on around me.  If the house is dead quiet, I just think, ah, louder music required
> 
> @Mr.Scott Do you use the Seasonic units for your benching?


How do you even hear that 1.2KW Platinum level PSU is beyond me...though your system specs say T (Titanium) and this say P (platinum).

Either way, I believe those have an eco mode where it doesn't spin up for a while.. I'd suggest using that. There is no reason a 1.2KW PSU with your system in the sig is running the fan. honestly. Hell, my 750W Evga G2 doesn't spin up in eco mode with a 4.5 GHz 7960x and 2080 Super....


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## Mr.Scott (Jul 15, 2020)

phill said:


> @Mr.Scott Do you use the Seasonic units for your benching?


I use Seasonic for everything. 
Only rig that doesn't have Seasonic in it is my SR-2 daily. That has an EVGA 750 in it, only because I got a screaming deal I couldn't pass on.


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## phill (Jul 16, 2020)

What's the smallest to biggest unit you use for Seasonic @Mr.Scott ?  I'm just curious as you push the bounderies of all things when it comes to these components and I bet more than most on this forum, that you'd be able to share a few power draws from lower powered PSUs that surprised you etc.? 

I mean as an example my SR-2 has a 1200w unit in it lol  I found I was hitting nearly 600w for just a CPU overclock when I was benching back a few years ago...  It's me on HWbot LOL


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## Mr.Scott (Jul 16, 2020)

Nice link. I remember you Phill. 
I have Seasonics from 430 to 1200 watts. It is my preferred brand after more than a decade of nothing but good luck. Only ever had a problem once, and their CS was outstanding.
Primarily for benching I'm on 750 or 1200.
Believe it or not, that is an 8 year old TurboCool 1200. Still cranks out stable voltage like no tomorrow.
My SR-2 / x2 5675 @ 4.3  (yes, that's my daily, lol) loaded hard will push not quite 700 watts on the EVGA 750, but it's only because I have a workstation vid card in it, otherwise it would be a lot higher. 750 watts would not be enough PSU to make me comfortable with a good gaming card in it.

My daily.


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## phill (Jul 16, 2020)

Thank you @Mr.Scott for your reply   I think you might have your answer now @PeterX9 



EarthDog said:


> At this point, you are really in the minutia. You can't go wrong with either.
> How do you even hear that 1.2KW Platinum level PSU is beyond me...though your system specs say T (Titanium) and this say P (platinum).
> 
> Either way, I believe those have an eco mode where it doesn't spin up for a while.. I'd suggest using that. There is no reason a 1.2KW PSU with your system in the sig is running the fan. honestly. Hell, my 750W Evga G2 doesn't spin up in eco mode with a 4.5 GHz 7960x and 2080 Super....


For some reason this 1200w unit is a little noiser than most of my other EVGA units..  I think the bearing in the fan might be showing some signs of where and tear as I do get the odd squeek from it.  I tend to not run it in Eco mode as for me I feel it gets too warm and when driving the 3900X + 2 1080TI's for folding, I'd rather have the fan going constantly.  My rigs when on, do never idle at all.  They are always under 100% load with the WCG  
The 1200w I have is a P2 (I'll amend that, thank you!! ) but I do have a 1600w T2 that's yet to be used....  I'll see if I can get a recording for you to show.  Everything is on the desk, not in a case as yet and I think this is half the battle with this...  Until I get the water loop sorted, it'll have to stay there because I don't have the bracket for the 14D air cooler to fit it properly too the motherboard.

But I digress..  @PeterX9 please post up some pictures and let us know what you think whenever you get the new PSU   Would love to hear about it and your experience too


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## PeterX9 (Jul 16, 2020)

I bought the fractal ion+ 760p, since the local retailer only had a 5-year warranty for the Seasonic while the fractal had 10 years (as stated by the company). 
I am now putting the build together however, this new PSU have 1x8 and 2x4 pin CPU power pin, and I'm not sure which of the 2 4pin should I plug onto the motherboard since both of them are compatible.

edit: compared both manual and it is the same, the lower 2 is the ground and the upper 2 is the 12V

I will post pictures tomorrow of the final build


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## phill (Jul 16, 2020)

From memory, any CPU 4/8 pin plugs I believe they only go in one way, so you might find that one is not the same as the other.  I noticed it a while back with my EVGA PSUs, but you can always check by looking at the connections on the board and pairing them with the side that fits.  I don't think that both sides of the 4 pin plugs would...  Don't quote me tho as it might be different with the PSU you have


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## PeterX9 (Jul 17, 2020)

This is my before cable management picture, i am however struggling to get tests running since hwmonitor doesnt show motherboard or cpu temperate and freqency(neither msi afterburner). The uefi shows the temps but maybe the apps arent updated with 10th gen cpus?


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