What type of PSU does a 4870 512 require?

[Spike]

I'm going to slap together a loaner PC and currently have a OCZ 500 or a Corsair 400 to use. I'm curious if either has enough juice to run a basic system, especially the 12v rail. The system specs will be:

e6550 (not OC)
4gb DDR2
4870 512
500GB Sata
1 120mm case fan.

Both would require the use of a dual molex to PCIe adapter as they only have a single PCIe each. Here are the PSU's

OCZ
http://www.newegg.com/Product/Produc...-012-_-Product
Corsair
http://www.newegg.com/Product/Produc...-008-_-Product

Thanks!

This was posted in video due to the specific knowledge of what this particular card would require. The PSU forum seems to be typically referring to entire pc needs. Mods, please move if this is still not appropriate for video.


Moved to PSU forum.

Super Moderator BFG10K.

 

[Lonyo]

Corsair should be fine, but the OCZ would obviously be better.

(The Corsair has 360w on 12v rail 30A single rail, the OCZ has 18A x2 on dual 12v rails, with a maximum amperage which seems to be 18A on both which is 432w)

System load will be well below 300w from the wall (so probably 250w max on the PSU), so either should be enough.

 

[iGas]

283 W -- 4870 max power consumption
30 W -- per HDD
30 W -- per CD/DVD/Blueray player
150 W -- or less for CPU
xx W -- motherboard

It look like you will need at least 450 W, but the 400 W corsair may be sufficient if it is a good PSU. It is unlikely that every device that you have will draw max power all at the same time.

 

[Lonyo]

283 W -- 4870 max power consumption
30 W -- per HDD
30 W -- per CD/DVD/Blueray player
150 W -- or less for CPU
xx W -- motherboard

It look like you will need at least 450 W, but the 400 W corsair may be sufficient if it is a good PSU. It is unlikely that every device that you have will draw max power all at the same time.

Where did you get that HD4870 power consumption number from?
It's a sub 200w card. TDP is only ~150w.
And HDDs don't use 30w, more like 15w.

 

[toyota]

283 W -- 4870 max power consumption
30 W -- per HDD
30 W -- per CD/DVD/Blueray player
150 W -- or less for CPU
xx W -- motherboard

It look like you will need at least 450 W, but the 400 W corsair may be sufficient if it is a good PSU. It is unlikely that every device that you have will draw max power all at the same time.

its good to over estimate but you literally doubled the power usage for each of those parts. lol

 

[iGas]

Where did you get that HD4870 power consumption number from?
It's a sub 200w card. TDP is only ~150w.
And HDDs don't use 30w, more like 15w.

Tom's Hardware

My bad. I was looking at crossfire number.

The actual number is 151.6 W for 1 card, and 268.6 W for 2 cards.

Actual Power Consumption And Current Requirements

HDD Diet: Power Consumption and Heat Dissipation 24~30W start up power requirement. IMHO, most devices require 2X~4X more power at start up than normal operation.

 

[toyota]

Tom's Hardware

that was for the entire system.

 

[maniac5999]

I'm running my OC'd 4870 and 940 on a Corsair 450VX (33A single rail) I'm also forced to use a Molex to PCIe adapter, and my P II 940 put out 125W stock, with a 65W dual you should be more than OK.

 

[Spike]

Ok, cool. I'll stick with the OCZ for now since the corsair is still "new in box" and I could always sell or use it later for another system.

Thanks for the input. I love having loaner PC's for lan parties, it's always nice to have extras for those without.

 

[Spike]

Just looked and noticed the OCZ does have two PCIe connectors but they are on the same cable. Should I use both of those or use one and an adapter on two molex cables to power the card? I don't know how many amps it needs and whether I should balance between the rails.

 

[tomoyo]

283 W -- 4870 max power consumption
30 W -- per HDD
30 W -- per CD/DVD/Blueray player
150 W -- or less for CPU
xx W -- motherboard

It look like you will need at least 450 W, but the 400 W corsair may be sufficient if it is a good PSU. It is unlikely that every device that you have will draw max power all at the same time.

Uh what magical forest did you come from? hdd's are 10w each. Optical drives are usually only one at a time and 10w or less. He already said he had a cpu that is 65w tdp or even way less. I think in general you're THREE times higher than normal.

 

[Spike]

My biggest worry was not powering the system as a whole, but powering the GPU specifically. To that end I'm now thinking it will work but I'm curious if it's better to use the two included PCIe connectors (both on the same cable and therefore the same rail) or to use one of them and a molex to PCIe adapter for the other connection.

 

[jiffylube1024]

The OCZ will work fine --- I just set up a computer for a friend using a 500W StealthXStream 500W and his 4870. A lot of newer built 500W StealthXStreams only have one 6-pin plug though (including the one I used) so if that's the case you need to use a 2x molex to 6-pin PCIe adapter.

283 W -- 4870 max power consumption
30 W -- per HDD
30 W -- per CD/DVD/Blueray player
150 W -- or less for CPU
xx W -- motherboard

It look like you will need at least 450 W, but the 400 W corsair may be sufficient if it is a good PSU. It is unlikely that every device that you have will draw max power all at the same time.

Back down to earth

The 4870 is a ~155W video card. HDD's typically consume 5-10W, while SSD's can take from 1-6W depending on model and load/idle.

CD/DVD/BDROM drives typically also take 5-10W.

Motherboards depend greatly on model, but usualy consume 10-30W. Newer models (ie Nehalem based chips and newer) use less power because many features of traditional northbridges have been moved onto the CPU such as the PCI-E controller, memory controller, etc.

 

[LiuKangBakinPie]

Radeon 4890 - 32A and a 550W PSU minimum
Radeon 4870 X2 CrossfireX - 1000W PSU minimum
Radeon 4870 X2 - 600W PSU minimum
Radeon 4870 - 32A and a 500W PSU minimum
Radeon 4850 - 30A and a 450W PSU minimum
Radeon 4830 - 26A and a 400W PSU minimum
Radeon 4770 Crossfire - 34A and a 750W PSU minimum
Radeon 4770 - 26A and a 400-500W PSU minimum
Radeon 4670 - 26A and a 400W PSU minimum

Corsair VX 550W - 41A on a single +12V rail
Corsair CX 500W - 34A on a single +12V rail
Corsair VX 450W - 33A on a single +12V rail
Corsair CX 430W - 28A on a single +12V rail
PC Power & Cooling Silencer 420W ATX - 30A on a single +12V rail
Corsair CX 400W - 30A on a single +12V rail
PC Power & Cooling Silencer 370W ATX - 27A on a single +12V rail

The Corsair 400w will be fine

 

[Concillian]

Just looked and noticed the OCZ does have two PCIe connectors but they are on the same cable. Should I use both of those or use one and an adapter on two molex cables to power the card? I don't know how many amps it needs and whether I should balance between the rails.

The current limit on the 6 pin is due to the molex connectors, not the wires themselves.

2 connectors + 1 wire = okay.

Most PSUs are designed this way.

It very likely dedicates one rail to the PCI-e connectors, which is ~200W, so it should be fine with a ~150W card.

 

[LiuKangBakinPie]

The current limit on the 6 pin is due to the molex connectors, not the wires themselves.

2 connectors + 1 wire = okay.

Most PSUs are designed this way.

It very likely dedicates one rail to the PCI-e connectors, which is ~200W, so it should be fine with a ~150W card.

Nope. Rails are the tracks on the pcb which the wires are connected to. Its monitored by a OCP chip. So rails are basically there for overcurrent protection. Usefull for psus thats 750w and higher. Below that theyre pretty much useless to have them. Thats why the top brands have a single rail for the psus under 750w