Go Back   Hardware Canucks > HARDWARE > Power Supplies

    
Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old May 17, 2009, 08:59 PM
Rookie
 
Join Date: May 2009
Location: Hamilton
Posts: 35
Default Crossfire requirements overrated?

All I seem to read about is how most people use a 700w at least for a 4870 crossfire build... I do all the calulations, and total draw required for your basic c2d system, even overlocked, is only 458 watts... Technically you should be fine with a good brand name 500 watt psu with a total of 44 amps on the 12v line..

More so, a PCP&C 610 silencer should be MORE then adequate, with room to spare correct? I believe this provides 52 a on the 12V..

Even ATI says a 600 watt unit is plenty. (brand name..)

I just wonder why half the people recommend something crazy like an 850 watt psu for a simple 4870 crossfire, with a normal rig (1-2 hdds 1 opti 2 case fans c2d or c2q)

I know its for safetys sake but still, a 600 watt would be more then enough and even at 90% load it should be safe for a couple of years..

Anyone get the same feeling as well?

It seems to me like alot of marketing going to our heads..
Reply With Quote
  #2 (permalink)  
Old May 17, 2009, 11:28 PM
MpG's Avatar
MpG MpG is offline
Hall Of Fame
 
Join Date: Aug 2007
Location: Kitchener, ON
Posts: 3,143
Default

There's definitely some marketing influence at work, certainly. But it doesn't pay to underestimate how much power a system is capable of drawing. Video card power consumption can go up surprisingly quickly, more and more people are tossing their dual-cores for quads, and programs like Furmark and IBT can make components exceed their own TDP's. Most ~750W PSU's are built more robustly than their smaller counterparts, and have fans that don't turn into leaf-blowers when stressed.

Honestly, if you can afford a pair of high-end video cards, you've got no business skimping on a PSU. And with the GOOD power supplies, the jump from the 500W realm to the 700W realm usually isn't too expensive. And if you do decide to try to run it all on a 500W PSU, make sure it comes with enough PCI-E connectors.
__________________
i7 2600K | ASUS Maximus IV GENE-Z | 580GTX | Corsair DDR3-2133
Reply With Quote
  #3 (permalink)  
Old May 17, 2009, 11:37 PM
Linus's Avatar  
Join Date: Apr 2007
Posts: 716
Default

Also bear in mind that "safe" and "quiet" are two different things. You run any PSU at 90% load and it's going to be loud or really hot. Neither of those things are good.

I like running a way overspec unit so that it stays nice and quiet.
__________________
Please note: I am not here to provide official NCIX support on these forums.

For faster (and official) NCIX service please contact our customer care team at www.NCIX.com (Canada) or www.NCIXUS.com (USA)

Heatware: http://heatware.com/eval.php?id=25647
Reply With Quote
  #4 (permalink)  
Old May 18, 2009, 05:50 AM
Soultribunal's Avatar
Moderator
F@H
 
Join Date: Dec 2008
Location: Mississauga
Posts: 8,062

My System Specs

Default

Linus has it bang on the money here, It is better to be over-spec'd and have the PSU running at nominal Temp and decent fan speed than have it almost fully cranked and hot.

Regards,
ST
__________________




"We know not why he calls for us, only that when he does we must answer" - DMP 2009

"Dear Iceberg, I am sorry to hear about global warming. Karma is a bitch. Signed - Titanic"

I would rather believe and find god doesn't exist than to not believe and find that he does.

www.realhardwarereviews.com
Reply With Quote
  #5 (permalink)  
Old May 18, 2009, 05:50 AM
yamawho's Avatar
Allstar
 
Join Date: Jul 2008
Location: Rosemere, Qc, Canada
Posts: 860
Default

I would use a 750 watt for crossfire I think ...

I do agree that most go overboard on the psu ... hype anyone?

It's good practice to factor in overclocking and 20% capacitor aging in the calculations.
Reply With Quote
  #6 (permalink)  
Old May 18, 2009, 06:18 AM
gingerbee's Avatar
Hall Of Fame
F@H
 
Join Date: Jan 2009
Location: Orillia, Ontario
Posts: 6,824

My System Specs

Default

750 watt crossfire sounds about right to me. would you drive your car every where you went with the engine red lined all the time. engine would not last that long same goes for power supply
__________________
Fav quote "One should strive to achieve; not sit in bitter regret." Ronin Harris
Reply With Quote
  #7 (permalink)  
Old May 18, 2009, 06:40 AM
sswilson's Avatar
Moderator
F@H
 
Join Date: Dec 2006
Location: Moncton NB
Posts: 14,416

My System Specs

Default

Heh... Everybody is on the same page here......

You don't want something running at 90%. Not only will it not be efficient at that kind of usage, PSUs have a tendancy to start putting out dirty power once you get up there.

The other thing to mention here is that most folks who question if 750W is too much are doing so because they want to save money on their build, so not only are they looking at running a system that's "right on the edge", chances are they're going to buy the cheapest 500 - 600w PSU they can find. Pairing an underpowered sub-standard PSU (rated to do 600W for 1 minute at -40c before blowing up) with a heavy sustained load is a recipe for disaster.

There's a huge difference between a quality 600W PSU ($100+) and a crap 700W ($50), and it ultimately comes down to getting what you pay for.
__________________
MSI Z87I Gaming AC / i5 4670K / 2X 4G Gskill 1866 DDR3 / XFX XTR 750 / EVGA GTX 680 SC+ 2GB / Intel DC S3700 200G / random 160G Sata HDD
Inwin 904 / Swiftech MCP655-b / Alphacool NexXxos XT45 120 Rad / 2X Scythe GT AP-15 / EK Supreme HF / Dell UltraSharp U2412M

Asrock AM1H-ITX / AM1 Athlon 5350 / 2X4G Gskill PC3-14900 / Intel 6235 Wi-Fi / 90W Targus Power Brick / 320G Seagate Momentus / Mini-Box M350 / 1X 22" Dell IPS / 1X 22" HP
Reply With Quote
  #8 (permalink)  
Old May 18, 2009, 07:12 AM
b1lk1's Avatar
Hall Of Fame
 
Join Date: Feb 2007
Location: Lindsay, Ontario
Posts: 2,489

My System Specs

Default

People just love overr-recommending power supplies. A PC P&C 610W power supply will eat up and spit out 4870 Crossfire. I often wonder just how many people are paid by power supply companies to whore oversized units out.
__________________
MY HEATWARE
Reply With Quote
  #9 (permalink)  
Old May 18, 2009, 07:14 AM
Rookie
 
Join Date: May 2009
Location: Hamilton
Posts: 35
Default

hahah yea ^ agreed

heres a linky for you guys.

Keep in mind that these wattages are taken at the wall for the entire system containing an Intel QX9770, 2GB Corsair, RAM, the video card(s), 3 WD Raptor Hard Drives, a DVD/CDRom, a floppy drive, and a Koolance Exos water cooling system.......458w.... for 4870 Xfire and allll that...


[H] Enthusiast - AMD Radeon HD 4800 Series

Bottom of page.
Reply With Quote
  #10 (permalink)  
Old May 18, 2009, 07:18 AM
sswilson's Avatar
Moderator
F@H
 
Join Date: Dec 2006
Location: Moncton NB
Posts: 14,416

My System Specs

Default

Quote:
Originally Posted by b1lk1 View Post
People just love overr-recommending power supplies. A PC P&C 610W power supply will eat up and spit out 4870 Crossfire. I often wonder just how many people are paid by power supply companies to whore oversized units out.
Key word there is "A PC P&C 610W" which will run a person $100+ so I hardly think that suggesting somebody would be best served with a quality 750W for $20 more would fall under the title of "whoreing".

Or perhaps you've got a secret supplier of quality sub $100 600W PSUs?
__________________
MSI Z87I Gaming AC / i5 4670K / 2X 4G Gskill 1866 DDR3 / XFX XTR 750 / EVGA GTX 680 SC+ 2GB / Intel DC S3700 200G / random 160G Sata HDD
Inwin 904 / Swiftech MCP655-b / Alphacool NexXxos XT45 120 Rad / 2X Scythe GT AP-15 / EK Supreme HF / Dell UltraSharp U2412M

Asrock AM1H-ITX / AM1 Athlon 5350 / 2X4G Gskill PC3-14900 / Intel 6235 Wi-Fi / 90W Targus Power Brick / 320G Seagate Momentus / Mini-Box M350 / 1X 22" Dell IPS / 1X 22" HP
Reply With Quote
Reply


Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
hd 4870x2 , psu requirements Jim Video Cards 18 August 22, 2008 06:39 PM
crysis system requirements SuperFriedFish Gaming 14 July 31, 2008 05:37 PM
Min Psu requirements DarkLloth Power Supplies 13 August 20, 2007 09:15 AM
Power Supply Requirements enaberif Power Supplies 9 August 1, 2007 02:22 PM
Power Requirements enaberif Power Supplies 6 July 10, 2007 06:20 AM