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I would like to replace my 800w BFG power supply, as it is a noisy monstrosity and I don't need that much power. I am very interested in these two PSU's, as I know Corsair makes a very high quality product.

Is there any significant difference between the two? If I had to choose a feature that would be the selling point, it would be how quiet it is, but I have been unable to find any review or information stating which is more quiet, the 620HX or 650HX. I also can't figure out why the 620HX is the more expensive model.

Maybe there's something even more quiet than these and out there and I'm just unaware of it.

Any help or information would be greatly appreciated, thanks!

What's your budget and how much power do you need exactly?
If that BFG PSU is working fine, I don't see much sense in replacing it, unless lower noise is worth the $$$ to you.

This is one of the best PSUs around, very quiet and efficient, but expensive.
http://www.newegg.com/Product/Product.a ... 6817151088

This is also a solid choice
http://www.newegg.com/Product/Product.a ... 6817139012

620HX vs 650HX, the latter has 30watts more power and is slightly more efficient, 85% vs 80%.

The 620HX has 3 +12v rails whereas the 650HX has a single +12v rail. That is why the 620 is more expensive.

I don't think that spec will affect how the psu sounds, but definitely will make a difference in performance in certain applications.

We have a lot of psu experts around here. I'm sure they'll chime in with further details.

BoBzeBuilder wrote:

What's your budget and how much power do you need exactly?
If that BFG PSU is working fine, I don't see much sense in replacing it, unless lower noise is worth the $$$ to you.

This is one of the best PSUs around, very quiet and efficient, but expensive.
http://www.newegg.com/Product/Product.a ... 6817151088

This is also a solid choice
http://www.newegg.com/Product/Product.a ... 6817139012

620HX vs 650HX, the latter has 30watts more power and is slightly more efficient, 85% vs 80%.

Budget isn't really a problem, as I am willing to spend some money to have a very quiet computing environment. For the longest time I thought my video card was the source of the noise coming from my system
but it turns out it is the PSU, which is very audible even with the system at idle. The 800w is already overkill. I'm running an E6600 at 2.9ghz, I have a 4850 which will soon be a 5850, and two hard drives. Nothing too extreme.

That SeaSonic model looks amazing, by the way. Looks like a nicer choice than either of those two Corsairs.

huh...620hx must be a new model? i know nothing about it...however, the 650hx is fine. if you don't need a modular power supply (i.e., you can deal with the extra wires of a non-modular psu), the corsair 650tx will save you a lot of money. i've seen that power supply on sale for very cheap too (it's not a bad deal anyway; the price is favorable for that class of psu). anyway, if quiet is what you want check out [url=http://www.silentpcreview.com/silent pc review[/url]. seasonic psus are also very good, and very quiet. several of corsair's psu are actually made by seasonic (such as the 650tx, which is a seasonic s12-II 600w). the x-series are nice, but very expensive. you need not spend that much to get a quality, quiet psu.

as far as power requirements are concerned, a good way to gauge what you need is find a good review of the video card you have, or will have and find out the load power consumption (nevermind what cpu or other hardware the review site uses). multiply that number by two, and that is the wattage psu you should get (psu's are most efficient at 50% load). my setup peaks in the 250-350 range at load, thus i have a 650w psu.

as it turns out, spcr has a review of the 620hx right here.

Actually, the 620HX is the older model and it looks like they may be letting stock to clear out, so there has been no price movement.

Or if you like to tinker and are competent enough to not electrocute yourself you could replace the fan in your current PSU.

maybe the 120mm Scythe Gentle Typhoon D1225C12B4AP-14 Case Fan (45.9 CFM/21 dBA)

eric93se wrote:

Or if you like to tinker and are competent enough to not electrocute yourself you could replace the fan in your current PSU.

maybe the 120mm Scythe Gentle Typhoon D1225C12B4AP-14 Case Fan (45.9 CFM/21 dBA)

My current PSU uses an 80mm fan apparently engineered to be as loud as possible at all times, so I'm not even sure it would fit.

But no, haha, I'd rather not risk the electrocution.

On paper the HX650 looks the better choice as it's not only cheaper but has a longer warranty and more connectors. However you're right that there don't seem to be any reviews comparing noise with the 620HX. To be honest, either should be very quiet in your system since you'll be running a pretty low % of the total load capability so the difference between the two should be fairly marginal. Even at max load, you should be just below the point where the fan starts to ramp up in both cases judging from the noise/power graphs on Corsair's website: HX620; HX650.

If you wanted to save some money, you'd actually be fine with the HX520 if that's still available (it seems to be disappearing...).

JJCDAD wrote:

The 620HX has 3 +12v rails whereas the 650HX has a single +12v rail. That is why the 620 is more expensive.

I don't think that spec will affect how the psu sounds, but definitely will make a difference in performance in certain applications.

We have a lot of psu experts around here. I'm sure they'll chime in with further details.

The 620HX and the 650HX both generate their +12 voltage off a single winding and have a single regulation scheme, thus they are both "single rails". The multiple "rail" business is part marketing, part poorly written ATX spec. Only a very, very few aftermarket supplies have multiple independent +12 rails (Enermax Galaxy, for one).

That said, the 620HX is an excellent supply. I've been using one for as long as they've been on the market (3+ years?) and have never had a concern with it's operation. It's very quiet, although the more efficient 650HX could be quieter still. Just depends on how Corsair dialed in the fan speeds.

650HX is quieter than the 620HX. Promise you, I went from one to the other. Also you'll see slightly higher efficiencies with the 650HX due to some upgraded internal guts.

sluggo wrote:

That said, the 620HX is an excellent supply. I've been using one for as long as they've been on the market (3+ years?) and have never had a concern with it's operation. It's very quiet, although the more efficient 650HX could be quieter still. Just depends on how Corsair dialed in the fan speeds.

Ditto on the 620HX.

I seem to recall hearing the 620HX was based off of a Seasonic PSU design. Is the 650HX in the same boat?

MaxTheLimit wrote:

I seem to recall hearing the 620HX was based off of a Seasonic PSU design. Is the 650HX in the same boat?

The 620HX and 520HX are made (OEM) by Seasonic. The newer line of HX products AFAIK are made by Channel Well (CWT).

Edit: grammar

I'm using a 620HX, and I wanted to cover two things not already covered (and please correct me if I'm wrong):

1. The 650HX can support two full 300W (8pin and 6pin each) GPU's, but the 620HX can only support one, as it has only one 6+2pin and one 6pin connector.
2. The 620HX, made by Seasonic, is probably more expensive at Corsair's cost simply because it's made by Seasonic. Now, Seasonic is a brand I automatically put trust in, but CWT, supposing that they made the 650HX, has been a company that has had to earn trust, which they have. But I'm willing to bet CWT is a cheaper supplier for them than CWT.

StuG wrote:

650HX is quieter than the 620HX. Promise you, I went from one to the other. Also you'll see slightly higher efficiencies with the 650HX due to some upgraded internal guts.

You must have had a defective 620HX- when it arrived, it was bar none the quietest actively cooled PSU in it's range. I've never heard mine.

MrJP wrote:

If you wanted to save some money, you'd actually be fine with the HX520 if that's still available (it seems to be disappearing...).

I've had my HX520 for almost two years now and it has been excellent. I highly recommend Corsair PSU's since I can't hear mine and I got what I paid for, quality.

Airmantharp wrote:

1. The 650HX can support two full 300W (8pin and 6pin each) GPU's, but the 620HX can only support one, as it has only one 6+2pin and one 6pin connector.

If it is just the connectors then this is not really an issue with adapters. However, if you really put 2 cards that draw 300W each then the 600W max output from the 3 rails of the 620HX can be worrisome (don't think cards draw the full 300W yet though).

Airmantharp wrote:

2. The 620HX, made by Seasonic, is probably more expensive at Corsair's cost simply because it's made by Seasonic. Now, Seasonic is a brand I automatically put trust in, but CWT, supposing that they made the 650HX, has been a company that has had to earn trust, which they have. But I'm willing to bet CWT is a cheaper supplier for them than CWT.

Jonny gave the 850HX pretty high marks. The TX series is also built by CWT on another platform and they seem to be pretty decent performers as well. I doubt the Seasonic made units are that much more expensive. Seasonic itself started off as an OEM and they still have a pretty significant OEM business today. Sure it may be more expensive than CWT (we never really know), but it should not be by much, or Corsair would not have entered the PSU market with them to begin with.

Do you really need/want modular cables? This is preference of course but I've never seen the need to pay more for modular, it's not terribly hard to tuck away extra wires. I don't have case windows though.

Do you really need a 600W+ PSU? They are really quite overkill for just about any normal-ish system that's using 1 GPU or possibly even two midrange GPUs. Don't let the connectors fool you, they are part of market segmentation too. If you use a single GPU a quality 500W-range PSU will be plenty.

If you don't need modular and decide not to over do it on your PSU with a 600W+ model the Corsair VX550 is a solid bet.

Anyhow thanks for posting this thread, I didn't know Corsair brought the 650HX out in the US. More efficiency is nice. Sadly they haven't done the same with 450HX yet and it doesn't look like they will.

I have a member in another forum that is claiming that the 650HX is actually still Seasonic. It's a tiny detail, but I'm waiting for him to cite his source, because I can't find anything on the thing- the 750HX/850HX are no doubt CTW, with the 750HX just now receiving TR's Gold award, on the front page.

themattman wrote:

MrJP wrote:

I highly recommend Corsair PSU's since I can't hear mine and I got what I paid for, quality.

Ditto - I've been using Corsair PSUs in system building for about the last three years and haven't regretted it. Virtually silent PCs (to the point that I hear the power-on beep echo inside the case), and out of probably 30 PSUs, I may have returned one as DOA, but I don't remember doing that for definite. None have died in the field. I had a tonne of problems with CoolerMaster PSUs (like 4 out of 5 DOA) before I started using Corsair, so I may be remembering that instead.

HX650: Newer, still bloody quiet and has the 7 year warranty to boot!

I've built around 5 systems now with this power supply, definitely is a mainstay in my recommendations.