Crossfire VS PSU question (yet again)

[sanpaper]

Hello,

My first post, so I apologize if this belongs in another section of the forum (ie Graphics Cards Or System Builds, etc).

Also, I know similar questions have been asked, but will all my searching (multiple boards), reading all the stickys, etc, I have yet to find a definite answer for my SPECIFIC setup. Querying tech-savvy friends have yielded split answers as well, as the online PSU calculator sites (Cooler Master, Corsair, etc)...

My question if fairly simple.

Will my Cooler Master 700w Silent Pro power supply be able to handle a 2nd MSI Cyclone Radeon 4890 HD OC in Crossfire based on my current system specs?

Intel Core i7 920 2.66 @ 3.38 (1.25v)
Aftermarket CPU cooler (can't remember brand)
Asus P6T Deluxe v2
3x SATAII HDD (7200 RPM, mixed sizes)
MSI Cyclone Radeon 4890 HD OC (stock clocks (880/3900))
3 of non-LED case fans, 1 LED 240mm fan.

That's it (no internal DVD/CD/Blueray, etc)

Any opinions would be greatly appreciated... and the reason for a 2nd MSI Cyclone is because a friend is upgrading his card and selling this one to me for practically nothing. But I don't want to shell out for a bigger PSU just to put this 2nd card in.

Thanks all....

 

[sparky13]

Wow I didn't think you could fit 2 Cyclones in crossfire. That heat sink it massive!

 

[sanpaper]

I fitted it, and close, but no contact.. =)

As did others, it looks like..

http://www.overclock.net/ati/582844-msi-4890-cyclone-crossfire.html


How about the actualy PSU question... any thoughts? Go or no go?

 

[JackNaylorPE]

Use this:

http://www.antec.outervision.com/

Will do all the math for you. Don't forget external things like USB mice, KB's , printers count too.....CPU fans, RAM

 

[sanpaper]

Thanks JackNaylorPE,

But I've used 3-4 different online PSU calculators, and they all come up with pretty much the same value: 468W (+- 20W). The web tools actually look pretty much the same.. lol

I would be satisfied with this, but when I used the one the Corsair site, they recommended their 850W PSU for the job...

So I'm back to doubts, hence I was wondering if anyone had a thought for my particular Cooler Master Silent Pro 700w... its a decent enough PSU, just not sure for this next step..


Keep the opinions coming, please.. Much appreciated!

 

[shadow187]

Every company overrates their PSU requirements so that you can't sue them if the PSU they said will work, didn't. You'll be fine; Cooler Master makes quality units.

 

[alikum]

Does Cooler Master Silent Pro 700W come with 4x 6-pin connectors?

 

[sanpaper]

alikum , you read my mind..

Just this second I opened up my case because I was asking myself this very question... and my PSU only has 2x 6pin connectors...

I guess that solves that question... no Crossfire for me, it seems, right?

The Radeon 4890 need BOTH plugs to be connected to function, I assume?

 

[shadow187]

http://www.newegg.com/Product/Product.aspx?Item=N82E16812706014

Now you have four 6+2 pins.

 

[sanpaper]

Smart man, shadow...

Thanks!

 

[JackNaylorPE]

But I've used 3-4 different online PSU calculators, and they all come up with pretty much the same value: 468W (+- 20W). The web tools actually look pretty much the same.. lol
!

Well I'd be worried if that didn't happen. Tho I think I cam up with about 550 for yours adding in like 5 USB's, 1 firewire, two CPU HSF's, 20% capacitor aging, 3 sticks of RAM, etc.

 

[alikum]

Now, before you proceed with that, just note no one can guarantee anything using the splitter that shadow187 mentioned. Best of luck.

 

[hellraiser06]

In a single word, Yes. Go ahead by all means.. Happy gaming

 

[JackNaylorPE]

Just this second I opened up my case because I was asking myself this very question... and my PSU only has 2x 6pin connectors...

http://www.newegg.com/Product/Product.aspx?Item=N82E16817171037

Specs say PCI-Express Connector 2 x 6+2-Pin

Found this:

http://www.legitreviews.com/article/1013/1/
"For those interested in putting one of these fine pieces of work into their PCs, ASUS recommends at least a 550 Watt power supply with at least 40 Amps available on the +12v rail. Let's take a closer look at the ASUS EAH4890 HTDI/1GD5 and then get to the benchmarks!"

Your PSU has 50 amps.

Looking here, if this is accurate

http://answers.yahoo.com/question/index?qid=20090920155626AA1S73o
"The issue is not with the PCIe power connector/adapter but most likely with the current (Amperes) that is being supplied. The +12V rail amps of power supply may not be sufficient. You need at least 36 amps for graphics card, processor circuit, fans and drive motors."

you are looking at 36 + 16 as a minimum based upon these sources which is slightly over your 50.

Here it looks like we have a consensus OK on a 850 watter
http://www.tomshardware.com/forum/268271-33-4890

I didn't have a lotta info on the rest of your system (memory ? externals ? etc) so i used a quickie PSU calculator
http://educations.newegg.com/tool/psucalc/index.html
It comes up w/ 904 w/ 3 sticks of RAM and assuming 1 OD

My bet is if you use the Antec one , you will find that an 850 is more than enough.

 

[sanpaper]

Figured I'd update on this...

I installed both MSI Cyclone 4890 OC cards tonight (stock clocks).

Everything fit well, no contact between cards or anywhere in case (Thermaltake Element S).

Put them in Crossfire, ran some tests and monitored some stuff (+12 values, GPU temp for each card, etc)..

Everything looks OK to me (but I ain't no expert):

- Min value for +12 was 11.78 and max was 11.93 (CPUID HW Monitor on Windows 7 64 bit) during gaming/stability tests
- GPU temps at idle is 51 deg C, and max 79 deg C after 10 mins FurMark stability test (1920x1080, 8x MSAA)
- GPU temps was 52 deg C and maxed out at 73 deg C after ~45 mins playing Far Cry 2, maxed out settings.

Played a couple hours of Far Cry 2, COD Modern Warfare Multiplayer and Borderlands, no crashes, etc.

Far Cry 2 with maxed out settings (DX 10, Ultra settings, VSYNC on and 8X AA, etc) plays with 61-65 FPS, and looks pretty damn sweet.

So looks like I'm fine for now. We'll see if its the same story once my PSU is 1+ year old. =)

Thanks for the contributions, folks..

Cheers