Corsair VX450W chirping sound--disappointing

[LM741C]

Two new builds this weekend both, Antec P180 case, I7-860, 120mm exhaust fans replaced with scythe, ATI 5670.

My problem is with the PSU , it chirps constantly and noticeably. I noticed it first on one system where I replaced the stock cooler with a thermalright MUX-120 (fan also replaced with scythe SFF21E). I exchanged one VX450W with another one but the chirping noise is still there. Checked the other system and the chirping is also there but not as noticeable since the stock cooler covers it a bit. It's not the fan (it is very quiet) since the sound is still present even when I stop the PSU fan so it appears to be some kind of coil noise.

So I now have a sample of three of these PSU's and they all chirp like crickets.

Three questions:
1. Somehow, I missed the chirping sound when I was assembling the system at home. I brought it to another placed and noticed it there. Could it be the power source (home vs commercial building) is affecting the PSU?
2. Anyone else notice the same chirping noises with the VX450's?

Unfortunately, the systems had a preset budget so I had to use the "cheaper" $75 VX's versus the Modu82+ or Antec Signature's I like using (somewhat disappointing too the PSU was in SPCR's recommended list).

3. Any recommendations for quieter PSU's around the same price range?

Thanks-

[Shmanky]

I bought the Corsair VX450W in 2007. It made the birdy noises. After some discussion about RMA and sending it back to Corsair in the Corsair support forums, I just took it out and bought a Seasonic 380W power supply.

[LM741C]

After doing some more research into this topic, it appears to be a common problem with some corsair (and other brand) PSU's. Possible causes:
1. Non-sinusoidal a/c shape (squarish when coming from UPS).
2. Too low power draw on 12v line (solution: turn off c1e and eist).
3. Graphics cards.

http://forum.corsair.com/v3/showthread.php?t=85166
viewtopic.php?t=41464
http://forum.corsair.com/v3/showthread.php?t=63500
http://forum.corsair.com/v3/showthread.php?t=80024
http://forum.corsair.com/v3/showthread.php?t=65245
(etc)

I will probably just exchange them for a different brand at the retailer I bought it from.

[LM741C]

An update on the chirping/buzzing corsair VX450W PSU's.

I turned off C3/C6/C7 states and EIST in bios as suggested by some of the previous links and the chirping/buzzing sound goes away.



So the problem appears to be some strange interaction between the intel powersaving features and the PSU when the CPU is in some low power state. So while there is workaround, I'm not entirely happy with the solution. The Intel C3/C6 states allow the cores to go into a lower power state or shutdown most of the unused cores. EIST allows additional powersavings by lowering the clock frequency, and thus power used, by the idling cores. There's several effects:
- The processor cores are running at full speed all the time.
- The processor is drawing a near constant amount of power from the PSU (on lavalys, it shows the current is constantly up). The varying load switching from the different C0 running and Cx idle states appears to be what's causing the PSU buzz/whine/chirp.
- The turbo-boost is also affected. The cores will no longer boost higher than when Cx/EIST is on if other cores are unused since the other cores are at "full speed" even if they are not being used since the extra turbo boost turns on if other cores are at non-zero Cx (C3/C6) states.
- Additional power consumed while core is idling at full speed.
- Additional power means additional heat generated.
- Additional heat means system cooling may need to work harder to cool the system.
- Additional cooling requirement may cause the fans to speed up possibly increasing system noise.
I measured some systems with/without C3/C6 and EIST and the additional power consumption at idle when those are turned off are:
i7/920 (quad core) --> +20W at idle when C3/C6 and EIST turned off
i3/530 (dual core) --> +7W at idle when C3/C6 and EIST turned off
I did not measure the i7/860 connected to the VX but it would probably come in at +15-20W additional at idle. At +20W, assuming the PC is on all the time and mostly "idle," this would result in additional ~175KW/h consumption per year (or $49/year additional at tier 3 pge rates).

(PS-I bought an enermax ECO80+ PSU for a possible replacement but I had to return it since the fan wasn't spinning, also it looks like the cables may not be long enough to route them through the back).

[Shmanky]

Thanks for posting your findings.

[LM741C]

In the interest of technical correctness, some fixes to my recent post.

- The processor cores are running at full speed all the time.
- The processor is drawing a near constant amount of power from the PSU

Strictly speaking, the power draw will not be constant since the processor would still be in idle state (probably sitting on a halt instruction) but the cores are maintained powered on and still clocked at full speed. What goes up however is the baseline idle consumption. Here is a before/after graph of power consumption from lavalys. The first one is with Cx power savings states and EIST enabled. The two peaks in the graph represent the CPU at 100% utilization and the throughs are during idle.



The next one is with both disabled.



The baseline, between the two peaks goes from about 7A to approximately 15A for a difference of ~10W. I'm not sure how lavalys gets the power numbers but I measured the 20W increase from the plug.

Second is the effect on idle temps, again the first one enabled.



The second one disabled.



The difference in idle temps is around 4-5 deg C on the hottest core. I didn't record the fan RPM's.