Corsair 750W PSU, enough?

[TridenT]

Do you think that the Corsair 750W Power Supply is enough for a 4870 Crossfire? Let's assume I have a overclocked Q9300 as well. Along with three hard drives and one optical drive. I have seen benchmark readings where they show 4870 crossfire using under 500Ws under load for the full system. (QX9XXX CPU that's OC'd included) So I figured 750W must be enough. But I'd like to see what you think.

 

[Noya]

I would assume so. It was $89 after rebate/google checkout from buy.com the other day. 750w / 60amp single rail / 80+ efficiency / 4 x 8-pin PCI-e connectors...it's like a PCP&C 750 for $40+ less. It doesn't say SLi/CF "certified", but we all know "certified" means licensing $$$ (just like THX with home audio).

 

[TridenT]

Originally posted by: Noya
I would assume so. It was $89 after rebate/google checkout from buy.com the other day. 750w / 60amp single rail / 80+ efficiency / 4 x 8-pin PCI-e connectors...it's like a PCP&C 750 for $40+ less. It doesn't say SLi/CF "certified", but we all know "certified" means licensing $$$ (just like THX with home audio).

Yeah, I bought it for 115.43 up front. (2 day shipping for only 5$ WTF?! ) So it'll be 105 after rebates. Sadly used up my Google coupon when it first came out. It's so depressing not being able to get free 10$!

 

[Jessica69]

You could try the links below....and I know it's hard to believe, but ATi actually has a list of cert'd power supplies for 4870's and 4870's in Crossfire.......



Single ATi card cert'd power supplies by manufacturer....


Crossfire cert'd power supplies.....4870's are listed first.....

 

[jdogg707]

I just hooked my system up and seem to be having issues with this PSU and Crossfire 4870's. Q9450 @ 3.21GHz, 4GB, 2x300GB Velociraptors

 

[MarcVenice]

Try unhooking one HD4870? Or a velociraptor? Tune down the overclock/voltage on your CPU? And let us know, if it's in fact the CPU that doesn't cut it. I think it should, based of AT's powerdraw figures from crossfired HD4870's, but then again, we won't know for sure untill someone tried it.

 

[jdogg707]

Originally posted by: MarcVenice
Try unhooking one HD4870? Or a velociraptor? Tune down the overclock/voltage on your CPU? And let us know, if it's in fact the CPU that doesn't cut it. I think it should, based of AT's powerdraw figures from crossfired HD4870's, but then again, we won't know for sure untill someone tried it.

Yea, I'm going to give it a try and see if I can isolate the problem. Can't unhook the raptors since they are in RAID. The PSU was working fine with a single 8800GTS 512 and everything else the same. Popped in the 4870's, booted up, installed the drivers and the system hung. Then I restarted, got into Windows, checked the drivers and temps and then the system just shut off. Booted it back up and it shut off again. This time I just left it off until I could do more research.

 

[TridenT]

Originally posted by: jdogg707

Originally posted by: MarcVenice
Try unhooking one HD4870? Or a velociraptor? Tune down the overclock/voltage on your CPU? And let us know, if it's in fact the CPU that doesn't cut it. I think it should, based of AT's powerdraw figures from crossfired HD4870's, but then again, we won't know for sure untill someone tried it.

Yea, I'm going to give it a try and see if I can isolate the problem. Can't unhook the raptors since they are in RAID. The PSU was working fine with a single 8800GTS 512 and everything else the same. Popped in the 4870's, booted up, installed the drivers and the system hung. Then I restarted, got into Windows, checked the drivers and temps and then the system just shut off. Booted it back up and it shut off again. This time I just left it off until I could do more research.

I would think that the 750 would be enough for that setup even. Do you think it could be you have a faulty one?
http://arstechnica.com/reviews...00-series-review.ars/7 For a ATI 4870 system it only takes like 233 at load. So with two I couldn't see this taking more than 750Ws.
http://images.anandtech.com/gr...062408145208/17144.png Even with Anandtech's own graphs it shows that it shouldn't take more than 500Ws for their bare system. (You have a few more things but I don't think it'd take more than 100W)

 

[jdogg707]

It's possible the PSU is faulty, but it has been working fine for about 6 months with no problems at all. Below are my complete system specs:

Intel Core 2 Quad - 3.21GHz @ Default Voltage
TRUE Black w/Noctura PF-12 Fan
Asus Rampage Formula x48 Motherboard
4GB (2x2GB) DDR2-1000
Azuntech X-Fi Prelude Sound Card
2 x Sapphire HD4870 Video Cards in Crossfire (Arctic Cooling Accelero S1 Rev. 2 attached)
2 x 300GB WD Velociraptor in RAID 0
LG Blu-ray Write/HD-DVD Drive
Corsair 750TX 750W PSU
Lian-Li PC-V1010B Mid-Tower Case (1x140mm, 2x120mm, 1x92mm Fans)

 

[MarcVenice]

If they crashed during gameplay I could understand, but in windows? If the PSU is really faulty it probably shouldn't even post, or boot all the way into windows.

 

[TridenT]

Originally posted by: MarcVenice
If they crashed during gameplay I could understand, but in windows? If the PSU is really faulty it probably shouldn't even post, or boot all the way into windows.

I wonder if it is overheating! This is definitely a possibility now that I think of it. One of my friends had the problem that his computer would just shut off and sometimes not come back on for 20 minutes. He could sometimes be fooling around in Windows and all good. But then it'd shut off. Looked inside his computer and the heatsink for the CPU had come off. Now I understand that it might not have come off for you but it could easily be a overheating problem. Have you checked the temperatures?

 

[jdogg707]

I have it up and running fine with one card now. I am going to check and see if it is overheating here in a little bit after I run a few more stability tests. I'll let you guys know what I find out.

 

[tuteja1986]

http://www.newegg.com/Product/...x?Item=N82E16817256007 >> certified

 

[jdogg707]

Ok, so after further testing I don't think it's the PSU, as it was able to boot up and complete some tests last night. It seems while overclocking and running crossfire, the NB on the x48 is running really hot (70C+). I rigged a fan over it and the temps dropped back some, causing me to run stable. For now I will limit my OC until I can get either get a case with better cooling or figure out a way to stabilize the NB permanently.

On a side note, I don't think the Crossfire array is working. I ran 3DMark06 last night and only received 18,886 on default, which is about what I would expect from a single card overclocked to 790/1000. I have Crossfire enabled in the drivers and have the bridge connected. When I try and run 3DMark Vantage, I get some weird chopping and tearing, like the frames are terribly out of sync. GPU-Z recognizes both cards, as well as the ATI drivers, and both of them are running at about 45C idle. Any ideas?

 

[Yellowbeard]

FWIW, TDP on those cards is about 150w or so. 2 in Xfire would be 300w which leaves 450w for the rest of the system.