Do I need to upgrade my power supply along with upgrades?

[Christobevii3]

What I have:

3800x2
2GB DDR 2 800
3 400GB Hard Drives in raid 5
1 320GB os drive
2 x DVD RW
Card Reader
Wifi Card
nvidia 570 sli
7900 GT
Antec neo 550 HE (earlier revision)
HT Striker Sound Card
4 x 120MM fans

What I'm moving to:

6000+ x2 (good deal) and eventually dual core penryn
8800GT and have another for sli but haven't decided to sli or not

My issue:
The power supply before the A4 revision was known to have minor issue with power ripples over a few 100mv for longer times than expected. I haven't had an issue with it yet but this has me worried adding about 120 watts more power load on it.

My reasoning for what I need in a power supply:
550watts running at 80% effeciency - 10% for heat loss leaves me about 400 watts of solid power with this power supply. Not too bad...but it gets worse.
Two 8800gt's in sli themselves use around 170-180watts, plus the cpu is rated at 125watts under load. That leaves me roughly 95 watts to run the motherboard, sound card, usb, wifi, 4 hard drives, and 2 cd drives. As I understand, most hard drives use around 10 watts spun up, which all won't be reading at the same time since my games are on the single drive and the raid 5 is more file stuff. But 95 watts is cutting it close.

I'd be more willing to try it if I had the later revision of the neo. The components in the power supply are equal to most brands 750 watt power supplies (not pc power and cooling, they're above everyone).

One other thing is I like quiet and running this power supply above 300watts racks up the fan speed. I should be fine at idle when sleeping but when gaming i bet the thing will peg out at full speed.

i've also seen people run a computer with similar specs, but with only one hard drive and an intel processor. The 3 extra hard drives and not having a 65 watt processor is where it gets iffy... Damn you early revision of this power supply.

So should I try running it and risk hosing a bunch of hard drives? Or should I spend the dough on the pc power and cooling 750 watt?

 

[jonnyGURU]

Originally posted by: Christobevii3

The power supply before the A4 revision was known to have minor issue with power ripples over a few 100mv for longer times than expected. I haven't had an issue with it yet but this has me worried adding about 120 watts more power load on it.

Is this documented somewhere (legit)? I'd like to see that.

Originally posted by: Christobevii3

My reasoning for what I need in a power supply:
550watts running at 80% effeciency - 10% for heat loss leaves me about 400 watts of solid power with this power supply. Not too bad...but it gets worse.

Actually, you have that backwards. 550W is DC output after accounting for any inefficiency. The fact that it's about 80% efficient only means you'll be pulling about 688W from the wall at full load as opposed to 700W or 720W or whatever with a less efficient PSU. You also don't have to compensate for additional wattage wasted as heat. That 20% that's not being converted to usable DC IS wasted as heat.

Originally posted by: Christobevii3
Two 8800gt's in sli themselves use around 170-180watts, plus the cpu is rated at 125watts under load. That leaves me roughly 95 watts to run the motherboard, sound card, usb, wifi, 4 hard drives, and 2 cd drives. As I understand, most hard drives use around 10 watts spun up, which all won't be reading at the same time since my games are on the single drive and the raid 5 is more file stuff. But 95 watts is cutting it close.

You're not cutting anything close. The most I've been able to measure DC from using a pair of GT's is just over 500W... and that was REALLY pushing it (multiple Orthos loops, COH, etc. all at the same time.)

Your PSU should be more than adequate.

 

[Christobevii3]

Here's where they said they had issues in a review of a previous revision. my power supply was bought 4 months before the first review they had issues. Click on the link there to see what the previous unit had issues with.

http://www.xbitlabs.com/articl...ay/atx-psu7.html#sect0

 

[jonnyGURU]

Well, the 100mV ripple on the +5V seemed to occur at a very high load (450W.)

It's hard to guess what's going on there since we don't know what the load on each rail was. The review just states what the total load on the unit was.

Still less ripple than an FSP Epsilon/Everest based unit.

 

[Christobevii3]

Also I mean to say run at 80% load not 80% effeciency. I figure I at least need a 10% buffer, so no more than 90% load at best and with 4 hard drives throwing heat into the thing in my antec p180, take another 10% since it is rated at 25C i believe.

So you think i should try it or what?

 

[jonnyGURU]

Well, I prefer to guestimate at a 50-70% load instead of an 80% load just to keep PSU temps down and prolong life, but even then a quality 550W (and the NeoHE is rated at 50°C) is more than enough for a pair of 8800 GT's.

Like I said, most I could pull is 500W DC and that was really trying to stress the PC out as much as possible.

Certainly, at the very least, it's worth "a try."

 

[badnewcastle]

You should be fine with the Antec 550w, I was using that psu with the system below and then my brother needed a psu because his went bad. So gave him mine and he is running a very similar system to mine now with my old Antec 550W both of us are running C2D's 6xxx with the 8800GT and 2GB of ram.

I don't know how it will fair with 2 GT's in SLI but w/1 card you'll be fine.

 

[John]

Originally posted by: jonnyGURU
but even then a quality 550W (and the NeoHE is rated at 50°C) is more than enough for a pair of 8800 GT's.

I concur, and certainly enough for the OP's build.