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psu for sli

G

gamekid

Gawd
Joined
Nov 1, 2004
Messages
626
what is a good psu for sli? i want to get a sli mobo and a pci-e 6800gt and then later get another 6800gt
 
PCP&C's are extremely expensive. I wasn't prepared to shell out £155 for a PSU. I bought a OCZ Powerstream 520W for £100 and I guarantee that will do the job just fine.

Anandtech reviewed using it. I'm sure you could easily get away with a lot less. A quality 420-450W PSU would probably work, even with 2 6800 Ultras.

Don't listen to people that say "You need a minimum of 600W and 40A on the 12V or you're screwed". Those people are insane and have too much money. Then again, anyone ready to do SLI is already ready to spend a crapload on the system, so I've got no argument here.
 
When dealing with dual opterons and my raid arrays, I went with PCP&C 510 for the higher quality. There are less voltage fluctuations than with my old 550 enermax and more power on the rails.

That probably isn't needed on everyday systems, probably even a sli setup without anything else really fancy. However, the cleaner the power, the more you can get out of your components.
 
asmielia said:
PCP&C's are extremely expensive.
Click to expand...

more accurately they used to be extremely expensive
now they are only expensive, and getting more reasonable by the day
since the baseline power requirements have been increasing
the average supply to run an average highend gaming rig now being in the +$100 dollar range, with Id say a median value of $130, and that extra $70 for the PCP&C wouldnt even be considered if it offered a slight advantage in a video card

what is really expensive is replacing components
if your going to run over a thousand dollars in just videocards
there is no excuse for not spending $200 on a PSU and getting a UPS
its cheap insurance

considering those cards are likely to be paired with CPUs that eat 7 to 9 amps on the +12V rail at full load, and that the cards are power hungry as well, having a little extra capacity (the 510 being 34A w\ 38A peak @ 40C) might just keep you from having to upgrade that supply in the near future because youve decided to add a few more drives, again its cheaper in the long run (config dependent of course)

as a note that Powerstream you purchased ins actually a Topower either a TOP-520PW or TOP-626P6 with a few options (its unclear as to whether the P6 line has been employed as the default OCZ offering since the beginning of Powerstream series, they are however the supplies being currently sold)

aside from the amps available on the Turbo Cools, most people adopt them for the extremely low AC Ripple (DM PARD) and load regulation, another consideration since the power is fed directly to the video card without the Voltage Regulation Buffer youd have with it being fed via the mobo and AGP slot

how catestrophic that can be is evidenced by the recall of the 600 watt ATX12V v2.0 offering from OCZ, as that initial batch of supplies was frying video cards right and left
 
No doubt, as I've seen you argue a million times, that the PCP&C is one high quality unit. However, I have owned many machines and many PSUs, and never once have I had an inadequate power supply in terms of volts or amps. My reason for upgrading has always been that a new motherboard has had a new connector, and therefore I couldn't use the old PSU (OCZ was partially a pre-emptive upgrade for an NF4 motherboard in the near future).

I don't know what prices are like in the US, but in the UK, the PCP&C is 50% more expensive. I consider £100 a lot of money to be spending on a PSU. I consider £150 to be outrageous.

Without a doubt, the PCP&C is a better supply than my OCZ. But I love my OCZ, and I guarantee it'll run any SLI rig without any issues. If you could get more than a few extra mhz out of any overclock using your PCP&C, I would be very surprised, and therefore it's not worth the extra money IMO.

Of course, you're the moderator of the Power Supplies forum, so it doesn't surprise me that you think differently.
 
asmielia said:
Of course, you're the moderator of the Power Supplies forum, so it doesn't surprise me that you think differently.
Click to expand...

what does that have to do with anything?
 
I'm not trying to insult anybody here. I'm just saying, he's the mod, so obviously he's big on PSUs. Hence his suggestion for buying the best.

IMO, it's overkill, but I'm sure plenty of you disagree with me.
 
actually Id agree in the overkill department with this caveate

Ive stated before that I have a pretty strict criteria for actually recommending a PCP&C
one of these three criteria needs to apply

1. overclocking, where eliminating the PSU as a possible source of instability is an objective (and a UPS needs to be included as well)

2. monster config, where you actually need the amps

3. investment protection, where the total cost of the rest of the config is such that it provides a by comparision, cheap insurance

in this case I felt the third definately applied, the second could easily apply dependent on config, and the first wasnt mentioned

while I did jump to addrerss the expensive comment, the PCP&C is by no means the only potential solution :p
the OCZ you mentioned or any of the other ATX12V v2.0 supplies with 30A or better on the combined +12V rails will easily power most "lite" to medium SLi configs ;)

shipping a heavy weight to the UK is a bitch M8
sorry if I jumped a bit too hard on the subjective value \ expense ratio :D
 
sorry, but i could not login yesterday for some reason :( . but i am going to go for sli but as i stated in the first post that i was going to get an sli board and one 6800gt now, and get another 6800gt later, this isn't going to cost too much extra (~$100) and i cant fit a $200 psu in my budget ($2000 for a completely new computer, moniter, keyboard, etc.) and i was thinking about this one:

ENERMAX Noisetaker AX ATX12V Ver 2.0 485W Power Supply, Model "EG495AX-VE SFMA 2.0" -RETAIL
http://www.newegg.com/app/ViewProductDesc.asp?description=17-103-458&depa=0

it says it has 15a on the +12v2 but in the picture it says 18a on both the 12v :confused: (i dont know much about psu's so sorry if my post sounds a little funny)
 
where can i buy that psu? i searched it on google and it only showed that same website, if i cant buy it doesnt really help any :(
 
try these http://maxpoint.com/buy/online.htm

you can also request it be stocked by newegg
there is often a delay between when a supply gets posted at the manufacturers website and its availablity in the channels
the ATX12V v2.0 supplies where listed for about a half a year before they started to make it into retailers,
there just wasnt the demand there to stock them
SLi is going to push that demand as it becomes more prevelant

if all else fails contact maxpoint and see if its in distribution yet and who is going to get it first
its likely the first supply will do the job as well, but you need to run the numbers

cut and paste



its very important to actually determine the amps per rail
and not all calculators are automatically the worse case senerio
I use > takaman's Power Supply Calaculator v2
which does have the option to set a utilization percentage, and to manually enter amp values for a given component
which is very handy if you have real world test values like
Power Consumption of Contemporary Graphics Accelerators: ATi
Power Consumption of Contemporary Graphics Accelerators: Nvidia
(all the better because they break out the draw between the AGP and the auxillary connector, which on an ATX12V v2.0 is on different +12V rails)
and various databases like Processor Electrical Specifications
(if the board has a +12V auxillary you add to the +12V otherwise it goes on the +5V rail,
and you convert the watts to amps for the appropriate rail, AMPS = Watts / Voltage)
or the actual spec sheets on the components (like say from Seagate)

that way Im able to run multiple calculations
first I do a "full" calculation, of all the additive maximums of the components
then for an ATX12V v2.0 supply or an EPS12V supply I repeat that for the +12V1, +12V2 and additionaly for EPS12V +12V3\+12V4 rails
for an ATX12V v2.0 the CPU, Mobo, RAM, PCI cards and AGP slot will be on +12V1
and the rest on +12V2, including the auxillary power to the Video Card

then I run a "realworld" worse case senerio,
Its just as likely Im helping someone calculate a NAS as a lean gaming rig
so a "spinup" calculation is the first criteria
all the fans and HDDs\RAID arrays at 100% value and a 25% value for the CPU\GPU, often that will tell me if a more powerful supply is needed simply to boot or if the NAS\SAN need to employ a controller with a delayed spinup option
(common on SCSI controllers, and found on quite a few ATA)
once the fans and HDDs are spinning they will drop to 1\4 of their full rating, so I recalculate with that value as a static load, and throw in a 100% CPU\GPU and single optical (full spinup draw) for a worse case senerio realworld

once I have those baselines I compare the supplies,

Interpreting the veracity of a manufacturer is the tricky part
since we dont get to actually see the engineering test specs
Mike Chin and Lee Garbutt are about the only PSU reviewers I actually trust

generally I start with deducting a third off the rated amps for temperature
and then start to match to the baselines, factor in thermal considerations (PSU placement, type of thermal solution for the rig,) and special factors like overclocking or usage patterns (NAS\Server\Workstation\word processor :p ),

when I actually make recommendations however I typical build in a healthier safety value than the "real world" worse case senerio unless someone has specifically stated they are running a UPS

BTW Enermax's veracity is quite high, but do factor in the loss of capacity for temperature
 
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