What Does it Mean When a PSU Has no Haswell Support

[Scarymonkeys]

I was looking at power supplies the other day and noticed on Newegg, in the details secton, the XFX 550W said it had no Haswell support. What does that mean? I don't see how something wouldn't be supported by Haswell.

[Scarymonkeys]

Noticed I was in the wrong section..

[Raudi_]

I was looking at power supplies the other day and noticed on Newegg, in the details secton, the XFX 550W said it had no Haswell support. What does that mean? I don't see how something wouldn't be supported by Haswell.

The really power states could make the PSU shut the system down (I think)

[jnmbhj]

I dont know where you see that I see Haswell ready 

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16817207013

[Scarymonkeys]

The really power states could make the PSU shut the system down (I think)

Is it okay to you use non-Haswell support PSU's?

[Raudi_]

Is it okay to you use non-Haswell support PSU's?

Yeah its fine to do.

[jnmbhj]

Even if it doesn't support haswell go into your bios and disable core 6 state 

[Scarymonkeys]

I dont know where you see that I see Haswell ready 

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16817207013

I still see "Haswell Support: No".

[Faa]

Haswell has a new C-state, C7 afaik, if your power supply isn't haswell ready you have to disable that C-State and it should work fine. Usually what happens is if your PSU isn't haswell ready, when the C7 state kicks in the system freezes requiring a reboot. C states are a power saving thing, 7th is the biggest one

[Scarymonkeys]

Even if it doesn't support haswell go into your bios and disable core 6 state

Alright. Thanks!

[Scarymonkeys]

Haswell has a new C-state, C7 afaik, if your power supply isn't haswell ready you have to disable that C-State and it should work fine. Usually what happens is if your PSU isn't haswell ready, when the C7 state kicks in the system freezes requiring a reboot. C states are a power saving thing, 7th is the biggest one

Now I understand..

[WoodenMarker]

Noticed I was in the wrong section..

I've moved the thread to the Cases and Power Supplies section. 

Just report threads to be moved in the future.

[quan289]

I was looking at power supplies the other day and noticed on Newegg, in the details secton, the XFX 550W said it had no Haswell support. What does that mean? I don't see how something wouldn't be supported by Haswell.

 

To answer your question, when Haswell goes into its C7 sleep state, it can reduce its power draw down to 0.05A, and this power is drawn from the 12v rail (as low as 0.6w).

There are certain PSUs that requires a certain balance in load for it to operate optimally between the 12v and the 3.3/5v rail. A change in load on one side can affect the voltages on the other. These PSUs are "group-regulated".

 

As to how Intel test PSUs to see if they are "Haswell Certified" is by putting 0.1A on 12v1 and .05A on 12v2, while the 3.3v and 5v will set at MAX load. This will cause the voltages of the +12v to spike up and the 3.3v/5v drop down significantly, where the voltages must stay within the +/-5% tolerance. If it doesn't, it will fail.

 

Here's an example: http://www.techpowerup.com/reviews/Bitfenix/Fury_750G/5.html

Scroll down to the graph at the bottom and look at "Crossload 1", as it's most similar to Intel's test. You will see that the 12v has spiked up to 12.734v (~ 6.1%), while the 5v has drop down to 4.720v (~ -5.9%). Both of which goes out of ATX specification.

_____

 

Should you worry? No. Intel's testing methodology is extreme and likely will not happen in the real world. This is because 1) you will not drawing anywhere near max load on the 3.3/5v rails and 2) you will typically have other components that draws from the 12v rail to increase the load such as your graphic card.

 

And let's say by chance you do run into problems, where you see some stability issues or that the voltages go so out of specs that it trips the over/under voltage protection of the PSU, you can simply disable it in the BIOS.

[Scarymonkeys]

I've moved the thread to the Cases and Power Supplies section. 

Just report threads to be moved in the future.

Alright, Thanks.