[SOLVED] 850W PSU Enough for this RTX 3080 Build?

[8PinConfusion]

Hi there,

Below is the build that I currently have with the Corsair RMx 850W. I'm looking to upgrade to either a 3080 or 3090, but I was informed that the 3090 had power spikes that the 850W couldn't handle. So instead of that, I was looking to upgrade to a 3080 instead. There doesn't seem to be much space in the case for a bigger PSU, and I'd prefer not to replace that right now if I don't need to.

Will the 850W be able to handle the all of the 3080 cards, or will certain ones still be too much despite the 750W recommendation? The retailers I'm looking at has the MSI Suprim, ASUS ROG Strix, Gigabyte Aorus Extreme / Vision / Gaming OC, and EVGA FTW3 Ultra in stock, but I wasn't sure if all of these will have too much power draw and I'd need to stick to the 2 x 8-pin cards.

PCPartPicker Part List
CPU: Intel Core i9-10900K 3.7 GHz 10-Core Processor
CPU Cooler: Cooler Master MasterLiquid ML360R RGB 66.7 CFM Liquid CPU Cooler
Motherboard: MSI MPG Z490 GAMING CARBON WIFI ATX LGA1200 Motherboard
Memory: Corsair Vengeance LPX 64 GB (2 x 32 GB) DDR4-3200 CL16 Memory
Storage: Samsung 970 Evo Plus 1 TB M.2-2280 NVME Solid State Drive
Storage: Seagate BarraCuda Pro 8 TB 3.5" 7200RPM Internal Hard Drive
Video Card: MSI GeForce RTX 2080 SUPER 8 GB GAMING X TRIO Video Card
Case: Cooler Master MasterBox TD500 Mesh w/ Controller ATX Mid Tower Case
Power Supply: Corsair RMx (2018) 850 W 80+ Gold Certified Fully Modular ATX Power Supply
Operating System: Microsoft Windows 10 Pro OEM 64-bit
Case Fan: ARCTIC F12 PST 53 CFM 120 mm Fans

Thanks!

 

[jay32267]

I read the post regarding the shutdowns with the RM850X.
I don't think the RM850X should shutdown under the circumstances he mentions.
In other words...I am a little surprised this>>>
"however any large GPU spikes as mentioned crashes the entire system, even if total load is way below 850W. "
is happening.
It's possible he may have a defective unit.
If it were me....I would get whatever GPU I wanted all the way up to a 3090 and try it.
You may be fine.

 

[TommyTwoTone66]

Yes, RM850x is more than enough for two 3080 or 3090 cards. With one card you are completely fine.

The other thread you linked has quite a bit of misinformation in it I’m sorry to say.

 

[8PinConfusion]

Yes, RM850x is more than enough for two 3080 or 3090 cards. With one card you are completely fine.

The other thread you linked has quite a bit of misinformation in it I’m sorry to say.

Oh, that's great to hear. I had it link to me from a previous post on here asking about the RTX 3090. Will there be any limitations on what RTX 3090 I could go for then? Or should even the higher-end ones (like the ASUS ROG Strix / MSI Suprim) even be fine with my build? Thanks!

 

[DSzymborski]

Yeah, it's likely the person in the other thread had another issue going on. There have been reports of 30 series issues with some good GPUs, but for different reasons that wouldn't affect the Corsair.

 

[jay32267]

"Will there be any limitations on what RTX 3090 I could go for then? "
No.
It should work with any 3090.

 

[8PinConfusion]

"Will there be any limitations on what RTX 3090 I could go for then? "
No.
It should work with any 3090.

Brilliant, thank you very much

 

[jay32267]

Brilliant, thank you very much

You're welcome.

 

[jonnyguru]

Hi there,

Below is the build that I currently have with the Corsair RMx 850W. I'm looking to upgrade to either a 3080 or 3090, but I was informed that the 3090 had power spikes that the 850W couldn't handle. So instead of that, I was looking to upgrade to a 3080 instead. There doesn't seem to be much space in the case for a bigger PSU, and I'd prefer not to replace that right now if I don't need to.

A CHEAP 850w like an EVGA GA850, cannot handle a 3090. A GOOD PSU like a RM850x can handle it with no problem.

 

[8PinConfusion]

A CHEAP 850w like an EVGA GA850, cannot handle a 3090. A GOOD PSU like a RM850x can handle it with no problem.

That makes sense. A lot I don't know about building PCs and especially PSUs, so I've learned a lot from here.

I've decided to go with the MSI GeForce RTX 3090 Suprim X 24G, which I'm thinking this build has enough for based on the comments?

Is there any downside to using 2 8-pin cables with this PSU and setup? 1 8-pin on it's own, and the second cable which has 2 8-pin connectors on it (to make up the 3 required). I don't want to mess with the existing cable management if I don't have to is all.

 

[TommyTwoTone66]

Is there any downside to using 2 8-pin cables with this PSU and setup?

Not really, no.

 

[novoalg]

I have the same PSU and I was trying to find accurate information about the power cables when plugging it in.
On my future 3080 there are 3x 8pin connectors , and my PSU only came with 2x6+2 pin PCIe cables that have a pigtail.
Is it safe to plug in those two cables with one of the pigtail occupying the third 8 pin slot in the card?
Would I need to get a third cable?

 

[jonnyguru]

I have the same PSU and I was trying to find accurate information about the power cables when plugging it in.
On my future 3080 there are 3x 8pin connectors , and my PSU only came with 2x6+2 pin PCIe cables that have a pigtail.
Is it safe to plug in those two cables with one of the pigtail occupying the third 8 pin slot in the card?
Would I need to get a third cable?

Yes.