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New silent PSU - Corsair AX750 or Seasonic X650?

Posted: Tue Oct 05, 2010 5:22 am
by Morten74
Basically - which one to get? The price is the same where I live (Denmark). I need it to power my current rig (see sig), and have enough power for future upgrades (more powerful CPU (i7?) and maybe CF with another 5850.

The X650 has gotten rave reviews whereever I read, on the other hand, the AX750 should be based on updated Seasonic PSU (X760)..?

Suggestions? Will be mounted in current setup (SOLO with Thermalright Ultra+Scythe S-Flex HSF).

:-) Morten

Posted: Tue Oct 05, 2010 7:01 am
by MikeC
In my testing of the AX850, I found only one significant difference from the X650 -- the fan & its controller on the latter is PWM; not so on the Corsair. The X650 sample did reach very slightly higher efficiency all around... but there are always sample variances, so it's hard to say whether this is indicative of all samples.

The X650 is at least double the max power draw of your rig; the AX750 a bit more. You could toss a coin or do the usual and go for more for the same $.

Posted: Tue Oct 05, 2010 1:34 pm
by Morten74
Hey Mike!

Thank you very much for your reply! I ended up ordering the AX750 as it was cheaper and has an additional 2 years warrenty - and the X650 is quite hard to find here in Denmark.

BTW - Love this site and your very thorough reviews!!!

Best regards


Posted: Tue Oct 05, 2010 7:11 pm
by zoob
I recently tried switching to a Corsair AX750 to see if it would stop my video card from buzzing under certain load conditions (the buzz also comes out of a Corsair HX620). The AX750 doesn't buzz with the video card, but instead emits a constant high-pitched squeal, and it continues until after the computer is off, and sounds like a dying animal when I shut off the hard switch.

i3 530
Gigabyte H55M-USB3 v1.0
XFX HD5770 1GB Single Slot
Corsair AX750

IMO the squeal is quite loud and annoying. I've switched back to my HX620 w/fan swap and will deal with the load buzz.

I was tempted to try out the X-400FL as it would be perfect for this system, but based on this experience I'm going to have to re-think what will be the PSU to go into here as it certainly does not require anything > 400W.

Possibly the same sounds that netmask254 is hearing in his thread here: viewtopic.php?t=60172&sid=0cdd8d8a0f3ab ... 3510914224