[SOLVED] Corsair RM650, 750 or 850i

TimH77

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Jul 21, 2017
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I've been going back and forth between different brands of PSU's, mainly the Phanteks AMP, ASUS Rog, Seasonic and Corsair RMx and RMi.

Current Setup:
  • Ryzen 7 2700x w/ Prism Cooler
  • MSI B450 Gaming Pro Carbon
  • Corsair Dominator Platinum RGB 2x16GB
  • 970 Evo M.2 SSD
  • WD Blue HDD
  • PNY GeForce 1050ti
  • Corsair CX650m
  • 3 Corsair ML120 Pro RGB
  • Thermaltake V3 Case
I have an MSI 2070 Super sitting here but it won't fit in the case otherwise I would have tried installing it even though the mobo only has the 8 pin (and not the additional 4 pin) for CPU power from the CX650m.

I'm trying to decide on a case between the Corsair 220t Airflow, Lian Li Lancool II or a Phanteks P600S. With the latter two I'll likely be adding 3 more Corsair ML120/140 fans.

I've basically decided on a Corsair RMI, to work with the other Corsair components, the Corsair software and monitor power (also adding a Commander Pro), but I'm stuck on which one to get- 650, 750 or 850.

I calculated my current load here, including with any foreseeable upgrades, and it came out at just under 500W.

I have never done any overclocking and I'm not sure I will, but at some point I'll update the processor to either a Ryzen 9 3900x or 3950x...which both are 105W like the 2700x currently installed.

The 650 and 750 both have 3 CPU(EPS)/PCIe connections on the PSU side. The 850 shows five. From what I read the CPU and PCIe connections are interchangeable.

Here's what I'm not sure about. I need connection for 8 pin EPS, one for 4 pin EPS, and the 2070 Super takes 8 pin and 6 pin.

Obviously the 850 has connections for each, but I didn't plan on paying over $200 for a PSU. With the 650/750 having three connections I figured one for each 8 pin and 4 pin EPS cable and the third connection for a dual 6+2 PCIe cable.

I was thinking since they actually include a dual 6+2 PCIe cable there is no issue with this, but I was also wondering if it would be better (power/load wise) for the 8 pin and 6 pin PCIe connections to have their own cable/connection to the PSU.

The best prices I found are-
RM650i- $115
RM750i- $177
RM850i- $220

MSRP for the RM750i is $149.99 and RM850i is $169.99, but on Corsair.com they are out of stock and no retailer has them for those prices, otherwise this wouldn't even be an issue...I'd get the 850.

I'm not sure how much of a 'cushion' over the 500W load is enough, say if I went with the 650.

I emailed Corsair to ask these questions, plus when the 750 and 850 will be back in stock, but the response I received didn't give answers and said they would pass the message to others...and no further response yet.

Any help would be greatly appreciated!




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Solution
The CX650m only has the one 8 pin for CPU power, which is how I'm running it now with the 1050ti.

One user said last week that the 2070 Super will likely require both the 8 pin and 4 pin for CPU power, and that the motherboard may not work without it (although I'm using it now with just the 8 pin for CPU power) . I'm wondering if the additional 4 pin is more for or necessary when overclocking? I do plan on upgrading to either a Ryzen 9 3900x or 3950x in the near future, but again, it's 105W same as the 2700x currently installed, so I don't think there will be much difference. Since I'm recording, editing and streaming video as well as some CAD, from what I understand the processor is most important and I don't see needing a 2080...

TimH77

Reputable
Jul 21, 2017
155
7
4,595
The CX650m only has the one 8 pin for CPU power, which is how I'm running it now with the 1050ti.

One user said last week that the 2070 Super will likely require both the 8 pin and 4 pin for CPU power, and that the motherboard may not work without it (although I'm using it now with just the 8 pin for CPU power) . I'm wondering if the additional 4 pin is more for or necessary when overclocking? I do plan on upgrading to either a Ryzen 9 3900x or 3950x in the near future, but again, it's 105W same as the 2700x currently installed, so I don't think there will be much difference. Since I'm recording, editing and streaming video as well as some CAD, from what I understand the processor is most important and I don't see needing a 2080 Super or TI... likely not but maybe some minor overclocking before (and after) upgrading to a 3900x or 3950x.

Another person on here...who was helping me decide on components...said something like the lower tier Corsair units like the CX650m are unreliable, specifically mentioning not having Japanese caps as well as a few other reasons.

I have to switch to a new case to fit the 2070 Super and planned on upgrading to a top tier, fully modular PSU at some point, so I figured I could get it done while swapping the case and save time and work. Plus, the RMi works with other Corsair components and the Corsair software.

If the CX650m will work I may just use it, put it in the new case and when I get a better/top 750W PSU I'll get sleeved cables then put it in.

You mentioned the 650 working, even with some minor overclocking. I imagine that would put it at the limit close to 650W, but how much use is too much... although I don't use it where resources would be pushed to their limit all of the time, i'd think if it was constantly close to 650W it wouldn't be ideal fir the PSU, correct?

I'm assuming you would use the CX650m, at least for the time being?
 
The CX650m only has the one 8 pin for CPU power, which is how I'm running it now with the 1050ti.

One user said last week that the 2070 Super will likely require both the 8 pin and 4 pin for CPU power, and that the motherboard may not work without it (although I'm using it now with just the 8 pin for CPU power) . I'm wondering if the additional 4 pin is more for or necessary when overclocking? I do plan on upgrading to either a Ryzen 9 3900x or 3950x in the near future, but again, it's 105W same as the 2700x currently installed, so I don't think there will be much difference. Since I'm recording, editing and streaming video as well as some CAD, from what I understand the processor is most important and I don't see needing a 2080 Super or TI... likely not but maybe some minor overclocking before (and after) upgrading to a 3900x or 3950x.

Another person on here...who was helping me decide on components...said something like the lower tier Corsair units like the CX650m are unreliable, specifically mentioning not having Japanese caps as well as a few other reasons.

I have to switch to a new case to fit the 2070 Super and planned on upgrading to a top tier, fully modular PSU at some point, so I figured I could get it done while swapping the case and save time and work. Plus, the RMi works with other Corsair components and the Corsair software.

If the CX650m will work I may just use it, put it in the new case and when I get a better/top 750W PSU I'll get sleeved cables then put it in.

You mentioned the 650 working, even with some minor overclocking. I imagine that would put it at the limit close to 650W, but how much use is too much... although I don't use it where resources would be pushed to their limit all of the time, i'd think if it was constantly close to 650W it wouldn't be ideal fir the PSU, correct?

I'm assuming you would use the CX650m, at least for the time being?
No the extra 4pin CPU plug is only for extreme overclocking like 5+Ghz on LN2 (Liquid Nitrogen). You won't need even if you OC a 3950X on water.

The CX650M is ok, not bad not the best.
When you get the 3950X and OC both CPU and GPU get the 750W.
These are the best PSUs:
Seasonic Focus/Prime and Corsair RM/TX.
 
Last edited:
Solution

TimH77

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Jul 21, 2017
155
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No the extra 4pin CPU plug is only for extreme overclocking like 5+Ghz on LN2 (Liquid Nitrogen). You won't need even if you OC a 3950X on water.

The CX650M is ok, not bad not the best.
When you get the 3950X and OC both CPU and GPU get the 750W.
These are the best PSUs:
Seasonic Focus/Prime and Corsair RM/TX.

Thanks for that info, definitely helps! I'll get epworth in a new case with the new GPU then I'll get the PSU, which then I'll be able to measure and get CableMod Pro cables at the correct length.

Yeah, the Seasonic Focus/Prime and the Corsair RMi and HXi were the main PSU's I was trying to decide between (I didn't look closely but I imagine the RM/RMi and HX/HXi are basically the same, respectively, except the 'i' works with iCUE).
 
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TimH77

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Jul 21, 2017
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What is the difference?

I guess I should have figured that since
RM/RMi and HX/HXi are basically the same, respectively, except the 'i' works with iCUE). Nope not the case , not the same.

What's the difference, other than iCUE? I said 'RM/RMi' in my OP but I was actually thinking of the RMx/RMi, which is probably still the same result.

I knew there was some difference(s) because when I was trying to decide I was relying on https://linustechtips.com/main/topic/1116640-psu-tier-list-40/, which has the RM and RMx as 'Tier A' and the RMi as 'Tier A+.'
 
What is the difference?

I guess I should have figured that since

What's the difference, other than iCUE? I said 'RM/RMi' in my OP but I was actually thinking of the RMx/RMi, which is probably still the same result.

I knew there was some difference(s) because when I was trying to decide I was relying on https://linustechtips.com/main/topic/1116640-psu-tier-list-40/, which has the RM and RMx as 'Tier A' and the RMi as 'Tier A+.'

So, FYI, there are websites that talk about PSUs outside of Linus Tech Tips. One good resource is Tom's Hardware (where you are currently posting this): https://www.tomshardware.com/reviews/corsair-rm750i-power-supply,4223.html

So an RMi not only has the LINK/iCUE capability of monitoring and (fan) control, but also an upgraded fan (FDB vs. rifle brearing).

For the HX vs. HXi, you're only really talking about the addition of the capacitors and sense wires to the cable set, which improves ripple and voltage regulation, but only marginally. Otherwise, the hardware is the same outside of the LINK/iCUE compatability.
 

TimH77

Reputable
Jul 21, 2017
155
7
4,595
So, FYI, there are websites that talk about PSUs outside of Linus Tech Tips. One good resource is Tom's Hardware (where you are currently posting this): https://www.tomshardware.com/reviews/corsair-rm750i-power-supply,4223.html

So an RMi not only has the LINK/iCUE capability of monitoring and (fan) control, but also an upgraded fan (FDB vs. rifle brearing).

For the HX vs. HXi, you're only really talking about the addition of the capacitors and sense wires to the cable set, which improves ripple and voltage regulation, but only marginally. Otherwise, the hardware is the same outside of the LINK/iCUE compatability.

On Corsair.com the 650/750/850 RMi's are out of stock (Corsair can't give me an ETA on new inventory), and everywhere I find the 750 and 850 the prices are basically the same as the HXi...$200 and $220.

I saw the RMi has a graphic that specifically mentions Japanese capacitors. The HXi doesn't show that graphic but the review mentioned above says what caps are in the HXi, Japanese. Surprisingly, the review said even though it is Platinum, it's less efficient.

I was wondering since I'd be paying the same price for either an RMi or HXi 750/850, which would be the better option?