RTX 3090 / 3080 (3x8 pin AIB) with Corsair SF750 question

[Jurrunio]

26 minutes ago, BTGbullseye said:

"(and this is not just the case of AMD, but all other vendors)"

 

Nvidia is the exact same.

"this" refers to "not having dedicated monitoring for minor rails". We know Nvidia cards monitor right through the power connectors, otherwise shunt mods wont work

[BTGbullseye]

1 hour ago, Jurrunio said:

"this" refers to "not having dedicated monitoring for minor rails". We know Nvidia cards monitor right through the power connectors, otherwise shunt mods wont work

And nobody has even tried doing a shunt mod on a 5700 XT, so we don't know that it doesn't monitor there. You keep wanting to paint Nvidia as superior, but you're not doing an apples to apples comparison to do it.

[LJA]

On 9/6/2020 at 8:40 PM, talos91 said:

To my fellow SF750 owners, if anyone is getting an AIB 3x8 pin RTX 3080 / 3090, are you going to run the 2 x 8 pins from one rail and use the 2nd rail for the last 8 pin? Is this safe? Nvidia recommends using separate cable connections for each 8 pin connector, i was wondering if this was the same for Board partner versions.

 

 

I noticed the SF750 has 2x GPU cables and 2X CPU 8 pin cables which kinda make no sense for an SFX PSU. I don't understand why they would include 2 x 8pin CPU cables. I don't think i've seen an ITX board require more than 1 x 8 pin connector. Is it safe to connect the extra CPU 8 pin to the 3rd 8 pin connector on the 3080/3090?

 

 

Sorry for all the questions and bad structure, i'm just wondering what i need to do to prepare for my upcoming card. Thanks!

Hi, english ain't my first language so I'm a bit confuse. I have a SF 750 and I mighjt upgrade to an 3080 in the future. From what  you are saying, the new cards uses three pcie cables? I don't really get what is the AIB 3x8 pin stuff. I'm currently running a 1080 ti connected with the two PCIex cables that come with this PSu, that cable configuration won't be enough to certain 3080 or 3090 models? Thanks in advance!

[BTGbullseye]

5 hours ago, LJA said:

From what  you are saying, the new cards uses three pcie cables? I don't really get what is the AIB 3x8 pin stuff.

The cards coming directly from Nvidia will have a 2x8-pin adapter in the box, and will run off that. Almost all the other card vendors (EVGA, MSI, Gigabyte, etc) are using 38-pin connectors on the board, because it's part of the reference design. The Founders Edition card from Nvidia is not a reference design this generation.

 

If you're only able to use 2x8-pin connectors, then a founders card is the way to go. If you have 3 connectors available, even if it's only on 2 cords, than you can still do any of them.

[LJA]

21 hours ago, BTGbullseye said:

The cards coming directly from Nvidia will have a 2x8-pin adapter in the box, and will run off that. Almost all the other card vendors (EVGA, MSI, Gigabyte, etc) are using 38-pin connectors on the board, because it's part of the reference design. The Founders Edition card from Nvidia is not a reference design this generation.

 

If you're only able to use 2x8-pin connectors, then a founders card is the way to go. If you have 3 connectors available, even if it's only on 2 cords, than you can still do any of them.

Thanks man, but the language barrier still makes me struggle to fully understand the situation.

Let me tell what are my doubts:

 

. When you've mentioned "If you have three connectors avaiable", are you reffering to three connectors/slots in the PSU to plug PCIe cables? If it's the case, I don't have them, since I have the SF750 with only two slots to connect PCIe cables.

 

. Or you are reffering to having: three 8 pin PCie cables, or at least two cables with double  8 pin connectors (6+2)?

 

To resume: 

Founders cards have a single new connector that comes with an adapter in order to use a single double 8pin cable (not recommended) or better use two 8 pin cables, each one connected to one each side of the adapter.

And other card vendors designs have three 8pin connectors in the card that ideally must be plugged to three  PCIe  slots in the PSU but it might be feasible to use just 2 cables:

both connected to the only two PCIe slots that I have in my SF750 and one of those cables must be connected to TWO 8pin slots in the VGA and the other cable connected to the  third  VGA 8 pin slot. And this last solution being discussed here as not ideal?

 

If that is the case.t sucks for ITX builds and down here in Argentina it's even more difficult to grab a Founders edition. But I might got it entirely wrong.

[BTGbullseye]

1 hour ago, LJA said:

. Or you are reffering to having: three 8 pin PCie cables, or at least two cables with double  8 pin connectors (6+2)?

This.

[LJA]

1 hour ago, BTGbullseye said:

This.

Thanks for the help and patience!

[BTGbullseye]

3 minutes ago, LJA said:

Thanks for the help and patience!

Any time.

[Deli]

On 9/7/2020 at 1:40 AM, talos91 said:

To my fellow SF750 owners, if anyone is getting an AIB 3x8 pin RTX 3080 / 3090, are you going to run the 2 x 8 pins from one rail and use the 2nd rail for the last 8 pin? Is this safe? Nvidia recommends using separate cable connections for each 8 pin connector, i was wondering if this was the same for Board partner versions.

 

 

I noticed the SF750 has 2x GPU cables and 2X CPU 8 pin cables which kinda make no sense for an SFX PSU. I don't understand why they would include 2 x 8pin CPU cables. I don't think i've seen an ITX board require more than 1 x 8 pin connector. Is it safe to connect the extra CPU 8 pin to the 3rd 8 pin connector on the 3080/3090?

 

 

Sorry for all the questions and bad structure, i'm just wondering what i need to do to prepare for my upcoming card. Thanks!

I know there are four 8-pin CPU/VGA sockets for either CPU or GPU on the SF 750. Some M-ATX mobos have one 8-pin and one 4-pin sockets for the CPU. And some compact M-ATX cases use SFF power supply. That explains why you see two 8-pin CPU cables.

 

In case you only need one 8-pin CPU cable. There are three sockets left for the GPU. If the card you choose requires three 8-pin VGA cables. You can buy an extra cable. Or, I think it is fine to connect the graphics card with just two. One used as "daisy-chain" way, so two cables can connect to three sockets/connectors. A single 8-pin connector can handle 150w of power. So two cables, plus the PCIe shot can supply 75w of power, should be enough for the 3080. Although we'll have to wait until some reviews and testes then we know how much power the 3080 actually draws.

 

 

[MrsBuklao]

On 9/15/2020 at 12:53 AM, BTGbullseye said:

The cards coming directly from Nvidia will have a 2x8-pin adapter in the box, and will run off that. Almost all the other card vendors (EVGA, MSI, Gigabyte, etc) are using 38-pin connectors on the board, because it's part of the reference design. The Founders Edition card from Nvidia is not a reference design this generation.

 

If you're only able to use 2x8-pin connectors, then a founders card is the way to go. If you have 3 connectors available, even if it's only on 2 cords, than you can still do any of them.

Hey. I was googling around on this topic as i am sure many others are currently doing. Most people have the problem of owning a PSU with only 2 dedicated PCI-e outputs. Almost everyone with a PSU has the 8pin cables with daisy-chained 2x6+2pin on one end.

So, are you sure that us with 750W+ PSU, can run an AIB 3080 or 3090(3x8pin), with 2 cables going from the PSU to the card, where one cable uses daisy chained 2x6+2pin?

 

So 2 cables, 3 connectors. And from what i have read online so far, the one cable that is 8to8 should be on first port, and the daisychained one on the second-third port, for extra stability?

 

Thanks for your help, i tried to write it clearly so future googlers might get their answer once you answer. @BTGbullseye

[jasonc_01]

2080ti spec is 250w, my FTW3 pulls 378w overclocked.

 

So I asked you before why are you bothering to look at triple 8 pin 30 series cards when you have an sf750. A triple 8 pin 30 series could pull up to 525w round about, so you have less than 225w for the rest of the system.

 

I'll tell you my OC'd 10850k and 2080ti pulls 768w from the wall and outputs 700w-710w.

 

So looking at triple 8 pin cards is a waste of time because 750w is not enough. Silverstone has an 800w which still isn't enough. They are supposed to have a 1000w SFXl power supply available but so far nothing. 

[BTGbullseye]

1 hour ago, MrsBuklao said:

So, are you sure that us with 750W+ PSU, can run an AIB 3080 or 3090(3x8pin)

It depends entirely on the quality of the PSU. There are several 650W PSUs I would trust way more than several 1000W units. Also, 80+ certification is meaningless as to whether or not they'll light your house on fire.

 

Tier A or B with 650W at minimum from this list for the RTX 3070/3080, and 750W minimum for 3090. (note that this is the absolute minimum, not recommended) Recommended is 750W+ for 3070/3080, and 800W+ for 3090.

 

1 hour ago, MrsBuklao said:

with 2 cables going from the PSU to the card, where one cable uses daisy chained 2x6+2pin?

 

So 2 cables, 3 connectors. And from what i have read online so far, the one cable that is 8to8 should be on first port, and the daisychained one on the second-third port, for extra stability?

That would be my suggestion, yes. Note that the "first" port is the one closest to the IO shield.

[MrsBuklao]

9 hours ago, BTGbullseye said:

It depends entirely on the quality of the PSU. There are several 650W PSUs I would trust way more than several 1000W units. Also, 80+ certification is meaningless as to whether or not they'll light your house on fire.

 

Tier A or B with 650W at minimum from this list for the RTX 3070/3080, and 750W minimum for 3090. (note that this is the absolute minimum, not recommended) Recommended is 750W+ for 3070/3080, and 800W+ for 3090.

 

That would be my suggestion, yes. Note that the "first" port is the one closest to the IO shield.

Thank you for your answer! Seasonic GX 750 seems to be an A-tier PSU, and the one i have.

I'm running a Ryzen 9 3900x and will get a 3090 ROG. Keep going with same PSU or buy a 850w?

[BTGbullseye]

4 hours ago, MrsBuklao said:

Thank you for your answer! Seasonic GX 750 seems to be an A-tier PSU, and the one i have.

I'm running a Ryzen 9 3900x and will get a 3090 ROG. Keep going with same PSU or buy a 850w?

It's good enough. The Ryzen CPUs don't use as much power as Intel chips, so the 750 is good. You will be at the upper end of the efficiency curve, (not power limit, that will be about 200W away, which is good) but only at maximum system power draw.

[Phantom-NcaseM1v6.1]

On 9/25/2020 at 10:43 PM, BTGbullseye said:

It depends entirely on the quality of the PSU. There are several 650W PSUs I would trust way more than several 1000W units. Also, 80+ certification is meaningless as to whether or not they'll light your house on fire.

 

Tier A or B with 650W at minimum from this list for the RTX 3070/3080, and 750W minimum for 3090. (note that this is the absolute minimum, not recommended) Recommended is 750W+ for 3070/3080, and 800W+ for 3090.

 

That would be my suggestion, yes. Note that the "first" port is the one closest to the IO shield.

Can you post a picture of this to illustrate?

[BTGbullseye]

4 hours ago, Phantom-NcaseM1v6.1 said:

Can you post a picture of this to illustrate?

A picture of what?

[SuperDiogenes]

On 9/16/2020 at 12:32 PM, Deli said:

A single 8-pin connector can handle 150w of power. So two cables, plus the PCIe shot can supply 75w of power, should be enough for the 3080. Although we'll have to wait until some reviews and testes then we know how much power the 3080 actually draws.

New dude here. Came across this thread while googling.

 

Where's this 150w per 8-pin connector number being pulled from? I'm trying to find out the limits of my SF750 to see if it is causing my brick wall when it comes to OC'ing my 3080Ti. It's very likely the power limit on my particular GPU but just ruling out all possibilities to see what I can do to tweak it.

 

Cheers