what does the word "compatible" mean exactly?

[GunsMadeAmericaFree]

When talking about processors and power supplies, what does the word "compatible" mean?

On another website someone posted a deal for an Antec VP-450 power supply for 15 bucks. I had been looking for an efficient power supply for a casual game PC (older games) for my kids, and wanted to see the efficiency curve for this. I found some info here:

http://www.hardwaresecrets.com/article/Antec-VP450-Power-Supply-Review/1487/7

Looks pretty good, getting 85% efficiency at a 50% load. It is doubtful that the load on this thing would ever go above 25% on our machine.

Anyway, someone got on there and kept going on and on about it not being compatible with Intel Haswell processors. I felt this was unfair, because it makes it sound like it won't work at all in a stable manner. I did some digging and found a few posts where Haswell users described the system not coming out of low power state properly. They had to disable the newer low power setting for Haswell, but then the system was stable.

He kept saying not to buy the power supply because it is not compatible with the newer Haswell processors.

Compatible by definition means that two things can coexist, or work together.

To me, incompatible would be:

A) someone trying to force an AGP video card into a pci-express slot on a motherboard
B) a driver trying to fill up his gasoline car with Diesel fuel

They just won't work, and something is probably going to be ruined. (you'll lose some money)

I'm not sure if this qualifies. Haswell and the Antec VP-450 are reported to work together fine by a couple of folks online who disabled the Haswell low power feature.

So, is this a case of true incompatibility, or just a case of having to tweak a feature setting in order to make the two compatible?

 

[nickbits]

All features don't work equals incompatible

 

[GunsMadeAmericaFree]

All features don't work equals incompatible

I wasn't so sure - I mean, if you want to be technical, they can work together 99.999999% of the time, but that one feature evidently has been reported to cause a few issues for some people, until they disable the ultra low power setting. Then again, the Newegg website lists it as being fully Haswell compatible. If it isn't, then I would imagine that someone could get after them for improper advertising, if not unethical behavior.

 

[OlyAR15]

Personally, I wouldn't bother with a PSU that has issues, even if it is sporadic. There are so many other good PSUs without this issue. Trying to save a few bucks on something as vital as a power supply is, IMO, not smart.

 

[GunsMadeAmericaFree]

Personally, I wouldn't bother with a PSU that has issues, even if it is sporadic. There are so many other good PSUs without this issue. Trying to save a few bucks on something as vital as a power supply is, IMO, not smart.

Normally I just stick with whatever power supply comes with a case, but at the last minute I noticed that the optical drives in my parents' system were IDE, and the new motherboard is 100% SATA. I needed to remove the IDE drives as part of this upgrade, and then I realized that I might as well update the power supply to one with modern hookups as well.

It's definitely an upgrade over the old case default power supply. It's for an AMD based system, so no Haswell liability should apply here. Yet another reason for me to stay away from Intel, I guess.

 

[jonnyGURU]

"Haswell Ready" means the motherboard can go to sleep, putting as low as a 0.5A load on the +12V rail of the PSU, and come back out of that sleep mode. Nothing more. Nothing less.

For a PSU to handle this incredibly low load, it has to have DC to DC for the +3.3V and +5V rails. By using DC to DC, those rails convert power from the +12V rail, so even if the CPU drops into the C6/C7 sleep states that would normally reduce the +12V load to next to nothing, there's still some kind load on the +12V rail.

If the PSU doesn't have DC to DC, and the +12V drops to 0.5A or lower while there's still a load on the +3.3V and/or +5V, that creates a crossload and the PSU shuts off. To overcome this, you have to disable the motherboard's C6/C7 sleep state.

THERE IS NOTHING MORE TO "HASWELL COMPATIBILITY" OTHER THAN THIS!!!!

The computer will otherwise be perfectly stable.