Can my PSU handle it?

balkieb2002

I have a OCZ ModXStream Pro 600W PSU.

It's currently powering:
i5 processor
P8P67 Pro Mobo
12gb ram
HD 6870 1GB
2TB HD
few fans

I was thinking off adding a couple of extra hard drives - 1 normal and 1 SD?

Is this possible or am I pushing my PSU too far?

I was originally also going to get 2x6870 but I think minimum PSU for that is 750w.

-( i )- Wicker

You could try This to get a good estimate. I believe a hard drive uses less than 10W so I imagine you'll have no problem.

Edit:

Eboggles

balkieb2002 wrote: »

I have a OCZ ModXStream Pro 600W PSU.

It's currently powering:
i5 processor
P8P67 Pro Mobo
12gb ram
HD 6870 1GB
2TB HD
few fans

I was thinking off adding a couple of extra hard drives - 1 normal and 1 SD?

Is this possible or am I pushing my PSU too far?

I was originally also going to get 2x6870 but I think minimum PSU for that is 750w.

Two 6870s would be fine on a 600 watt, and HDDs only take 5 watts or something really low. SSDs even lower.

balkieb2002

-( i )- Wicker wrote: »

You could try This to get a good estimate.

Eboggles wrote: »

Two 6870s would be fine on a 600 watt, and HDDs only take 5 watts or something really low. SSDs even lower.

Thanks for that calculator - seems like ye said it should be fine.

Worked it out that 2x6870 (crossfire) plus 3 HD's @ 90% load = 460W so nice bit of breathing space.

My processor is an i5-2500K which I know is easily OC'd so I was worried that might also take it over/near the limit though with the worse case scenario of the estimated 150W headroom it should be fine.

Its a little bit more complicated than simply looking at total power because your PSU is multiple rail with max of 25A on any one rail and 42A total.

So looking at your PSU I think your GPU(s), HDD motor(s) and fans will all be sharing the +12V2 rail.

I would not recommend putting 6870 SLI on that. You will pretty much hit 25A straight away under load with just the GPUs. Leaving no spare capacity for the HDD motors and any other 12V peripherals.

Certainly with just the single 6870 it will be no problem adding some HDDs. Half a dozen no problem. For a HDD you want to allow about 1A at spinup (little bit less for green drives) on the 12V rail.

balkieb2002

Cheers for the info Deleted User
Thats makes it a bit more clearer. Just one question.

How do you know which rail is being used and can you force it use one or the other?

The upgrade of second card was just something I was looking at as a future upgrade but have no real need just yet as my comp is not really struggling with anything yet.

Good to know regarding the HDs though as they will be upgraded this week hopefully.

balkieb2002

balkieb2002 wrote: »

How do you know which rail is being used and can you force it use one or the other?

The upgrade of second card was just something I was looking at as a future upgrade but have no real need just yet as my comp is not really struggling with anything yet.

Good to know regarding the HDs though as they will be upgraded this week hopefully.

The specs of the PSU should tell you the configuration.





The 2nd pic is the 500W but it was just a picture i googled, the 600W is the same config.

So you can see that all the modular connectors are using 12V2. The other 12V rail (12V1) is supplied via the non-modular cables to your CPU.

That means the GPU and any other modular that uses 12V are all on the same 12V2 rail. So in total they should not exceed 25A. If your GPU is 150W then its pulling 12.5A (150/12), so you can see why SLI would be an issue.