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

[PeterX9]

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?

 

[agent_x007]

Unless LN2, you should be fine with one.

 

[maxfly]

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.

 

[PeterX9]

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.

 

[Vya Domus]

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.

 

[kayjay010101]

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.

 

[PeterX9]

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

 

[phill]

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'?

 

[PeterX9]

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.

 

[kayjay010101]

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.

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'?

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.

 

[PeterX9]

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.



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.

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.

 

[kayjay010101]

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.

 

[PeterX9]

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.

 

[phill]

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.

 

[PeterX9]

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.

 

[kayjay010101]

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.

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.

 

[arbiter]

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.

 

[phill]

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.

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.

 

[PeterX9]

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.

 

[kayjay010101]

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.

 

[EarthDog]

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.

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.

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

 

[PeterX9]

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).

 

[Assimilator]

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.

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/

 

[phill]

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

 

[PeterX9]

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)