[SOLVED] Corsair CX 750 with 2x PowerColor Red Devil RX 580

[Hatsuni03]

My friend gave me two PowerColor Red Devil RX 580 8GB graphics cards and I was wondering if my CX 750 power supply could run them both for maybe half a year or so till I get a better one?

Motherboard: Asrock 890FX Deluxe 4
Cpu: phenom ii x6 1055t 125w
Ram: 4x4 ddr3
Hard drives: 4 western digital 7200k

 

[jankerson]

How old is the PSU?

 

[Hatsuni03]

How old is the PSU?

About a year old

 

[jankerson]

I would run one card on it, you are pushing it with that PSU running 2 cards as they aren't exactly made for gaming machines in the 1st place.

You can try 2 cards if you want and see how it works, 1st hiccup I would pull one of the cards out and replace the PSU with a higher quality UNIT.

 

[jonnyguru]

CX750 or CX750M?

What color is the label? With green letters or grayscale?

If it's a CX750 (no M) with the grayscale label, it's perfectly fine for any dual card setup, despite what jankerson says.

The newest CX series use an LLC resonant front end with DC to DC on the +3.3V and +5V.

Even the CX750M has DC to DC on the secondary side, but it has a double forward front end. Perfectly adequate power for your build, but the transformer can make noise when running certain games and benchmarks. Still won't blow up on you, though.

 

[jankerson]

CX750 or CX750M?

What color is the label? With green letters or grayscale?

If it's a CX750 (no M) with the grayscale label, it's perfectly fine for any dual card setup, despite what jankerson says.

The newest CX series use an LLC resonant front end with DC to DC on the +3.3V and +5V.

Even the CX750M has DC to DC on the secondary side, but it has a double forward front end. Perfectly adequate power for your build, but the transformer can make noise when running certain games and benchmarks. Still won't blow up on you, though.

I said they can try it and see how it does.

So we will see how it does I suppose if he tries it.

I think he would be better off with an RMX however in the long run.

I wouldn't say any dual card setup however, some of those GPU's can pull well over 300W each, easily 350W each for some of them... Would be quite a lot for 2X PCIe cables.

I have seen my RTX 2080Ti pull like 365W when OCed, that's just one card.

The RX 580's pull like 240W so that's a rather large difference, a lot less.

 

[jonnyguru]

I said they can try it and see how it does.

So we will see how it does I suppose if he tries it.

I think he would be better off with an RMX however in the long run.

I wouldn't say any dual card setup however, some of those GPU's can pull well over 300W each, easily 350W each for some of them... Would be quite a lot for 2X PCIe cables.

I have seen my RTX 2080Ti pull like 365W when OCed, that's just one card.

The RX 580's pull like 240W so that's a rather large difference, a lot less.

Right. But a CX750 or CX750M can actually put out 750W continuous as long as temps are at or lower 40°C. So I don't see the issue.

 

[Hatsuni03]

The power supply is the CX 750 with the green and white letters and numbers. I put both cards in booted up just fine and installed the drivers. But right when I tried to start a stress test it rebooted so I’ll just stick with one card for now.

 

[jankerson]

The power supply is the CX 750 with the green and white letters and numbers. I put both cards in booted up just fine and installed the drivers. But right when I tried to start a stress test it rebooted so I’ll just stick with one card for now.

I saw that one coming.....

Yeah, that's not the good one so it's a smart move.

Upgrade the PSU as soon as you can to a better quality unit.

If you want a Corsair look at the RMX 750W, they are excellent.

Others are the FOCUS Plus or EVGA G2, both 750W.

I never recommend the CX or CXM series for anything but budget PC's or office machines. They seem to be slightly better than the other budget PSU's from the other makers for the most part. At least that's what they say anyway.

But I never recommend any budget PSU for any gaming PC no matter who makes it.

I prefer not to experiment with other peoples money.

 

[jonnyguru]

The power supply is the CX 750 with the green and white letters and numbers. I put both cards in booted up just fine and installed the drivers. But right when I tried to start a stress test it rebooted so I’ll just stick with one card for now.

You bought a four year old PSU one year ago? Wonder how long it was sitting on a shelf in a store.

If you want to know the manufacture date of a PSU, look at the serial number sticker. First two digits is year of manufacture. Second two digits is week.

I don't believe the reboot was due to not enough power. When a PSU is overloaded, the PC doesn't reboot. It shuts down. But I do agree with jankerson that a CX is not made for a gaming PC and certainly not one with dual GPUs. So before you add that second card and troubleshoot further, get a different PSU.

 

[jankerson]

You bought a four year old PSU one year ago? Wonder how long it was sitting on a shelf in a store.

If you want to know the manufacture date of a PSU, look at the serial number sticker. First two digits is year of manufacture. Second two digits is week.

I don't believe the reboot was due to not enough power. When a PSU is overloaded, the PC doesn't reboot. It shuts down. But I do agree with jankerson that a CX is not made for a gaming PC and certainly not one with dual GPUs. So before you add that second card and troubleshoot further, get a different PSU.

I see stores that are still selling the Green labeled units every now and then, mostly off Amazon or overseas. They have both the old and the new most of the time.

They must have been sitting around for a long time.

Never was sure if a PSU actually degrades sitting around in a sealed box.

 

[jonnyguru]

I see stores that are still selling the Green labeled units every now and then, mostly off Amazon or overseas. They have both the old and the new most of the time.

They must have been sitting around for a long time.

Never was sure if a PSU actually degrades sitting around in a sealed box.

Depends on the cap and the factory storing the cap.

It's not unusual for PSU factories to "horde" parts like capacitors for multiple reasons:

1. Long lead time
2. Volume pricing

But the factory has to be equipped to store these parts and I've been to a surprisingly large number of factories that aren't and have been disqualified during audits for not having proper storage temperature and humidity.

Once the PSU is assembled, you have a new issue. Is the PSU now being stored in an environment with proper temperature and humidity? That's beyond the PSU company's control after the PSU is sold off to a retailer. Often times the answer is "no". It's expensive to cool and dehumidify a warehouse! I dare say that some of the PSU company's own warehouses are too hot and too humid to be considered proper storage environment (imagine a warehouse in Taiwan or Florida... ).

If an uncharged cap sits, the ESR and leakage current and capacitance can change. The higher the temperature, the faster this happens. The storage conditions and shelf life at those conditions for a particular cap are in the capacitor manufacturer's data sheet, but if the actual storage conditions are outside of that range, all bets are off.

After so many years, we have to go through an exercise for old inventory or old components where we decide if it can be "reconditioned", "used elsewhere" or just scrapped. For capacitors, you can "reform" them by slowly energizing them until they reach their specified voltage. Of course, reforming takes time, so you have to consider the cost of paying someone to reform the cap vs. the cost of the cap itself.

Lots of product ends up "scrapped". Or you have a "fire sale" where you dump old product for nearly cost (if any of you guys are old enough to remember Ultra's "free after rebate" deals, that's because they had the ass end of a 20K piece order sitting in a warehouse for almost a year and they needed to go). Sometimes scrapping nets higher profits because you can write it off and if you don't and the older product ends up on the market and then fails, the manufacturer is still on the hook for the warranty. Also, when you scrap inventory, you have to be careful of who you hire to scrap the product. Sometimes the product ends up recondition and resold instead of scrapped. I've actually resorted to beating on the product with hammers and then spray painting all over it to make sure nobody tries to recondition it.

Of course, caps aren't the only part subject to a short life span. You have shelf life on PCBs and magnetics too. Pretty much anything with copper that is at risk of corrosion.

 

[jankerson]

Depends on the cap and the factory storing the cap.

It's not unusual for PSU factories to "horde" parts like capacitors for multiple reasons:

1. Long lead time
2. Volume pricing

But the factory has to be equipped to store these parts and I've been to a surprisingly large number of factories that aren't and have been disqualified during audits for not having proper storage temperature and humidity.

Once the PSU is assembled, you have a new issue. Is the PSU now being stored in an environment with proper temperature and humidity? That's beyond the PSU company's control after the PSU is sold off to a retailer. Often times the answer is "no". It's expensive to cool and dehumidify a warehouse! I dare say that some of the PSU company's own warehouses are too hot and too humid to be considered proper storage environment (imagine a warehouse in Taiwan or Florida... ).

If an uncharged cap sits, the ESR and leakage current and capacitance can change. The higher the temperature, the faster this happens. The storage conditions and shelf life at those conditions for a particular cap are in the capacitor manufacturer's data sheet, but if the actual storage conditions are outside of that range, all bets are off.

After so many years, we have to go through an exercise for old inventory or old components where we decide if it can be "reconditioned", "used elsewhere" or just scrapped. For capacitors, you can "reform" them by slowly energizing them until they reach their specified voltage. Of course, reforming takes time, so you have to consider the cost of paying someone to reform the cap vs. the cost of the cap itself.

Lots of product ends up "scrapped". Or you have a "fire sale" where you dump old product for nearly cost (if any of you guys are old enough to remember Ultra's "free after rebate" deals, that's because they had the ass end of a 20K piece order sitting in a warehouse for almost a year and they needed to go). Sometimes scrapping nets higher profits because you can write it off and if you don't and the older product ends up on the market and then fails, the manufacturer is still on the hook for the warranty. Also, when you scrap inventory, you have to be careful of who you hire to scrap the product. Sometimes the product ends up recondition and resold instead of scrapped. I've actually resorted to beating on the product with hammers and then spray painting all over it to make sure nobody tries to recondition it.

Of course, caps aren't the only part subject to a short life span. You have shelf life on PCBs and magnetics too. Pretty much anything with copper that is at risk of corrosion.

Makes a lot of since Jonny.

That clears it up.

 

[jonnyguru]

Moral of the story: Don't buy old PSUs.