PSU requirement for Triple SLI

[Glendor]

Here is my current system...

Antec Ninehundred case
MSI 890FXA-GD70 w/ latest bios
AMD 1055T 6x @ 3.5ghz OC
Corsair H50 cooler 28c Idle / 38c Load
2x4gb G.Skill Ripjaw DDR3
2x BFG GTX 275 OC in SLI
2x Seagate Momentus XT in RAID0
Muskin Enhanced 550w PSU
Win7 64bit w/ xDev SLI mod

The current system is running ROCK SOLID on the build above, but I'm thinking of either adding a 3rd GTX 275oc for triple-SLI. I'm concerned about the PSU.

Do you think I need to upgrade, and if so, to what level?

Glendor...



Moved to PSU forum.

Super Moderator BFG10K.

 

[JAG87]

I think you are under powered as it is, don't try 3-way on that PSU. And don't do 3-way either, it's not worth the trouble or the investment. You are better off selling your cards and buying one 480 or two 460s.

 

[vanilla guerilla]

mushkin psu's are terrific, i ran 9800gx2 quad sli for 6 months with a mushkin 650. but i have to tell you that the 550 might be a bit lightweight for 3x 275. maybe something like a true power new 750.

 

[Henry Chinaski]

Note that a couple of GTX275 (without OC) can pull from your PSU even 450W at full load... Nowadays you are taking your PSU to its very limit. I would never do what you are doing.

 

[bucd]

Yep...need an upgrade for sure if you going tri sli gtx 275s. A good 750w should do the job.

And i will have to agree with jag87 about tri sli not being worth the trouble, unless of course you are folding....then by all means.

🙂

-D

 

[jonnyGURU]

Mushkin PSU's are Topower... for one. Twom for 3-way SLI, you're going to want at least 750W+.

 

[Glendor]

Okay, I was only 'thinking about' trying triple SLI, but I'm convenienced that it may not be worth it, both peformance wise, and because I would need to upgrade my PSU. Instead, I'll probably throw in an older video card for dedicated PhysX processing instead; something that doesn't require additional power, like a 9500GT w/ passive cooling.

My Mushkin PSU has been doing so well, I hate to replace it. I reran all my benchmarks last night, and the temp output at the PSU fan never seemed to increase during this stress test. Maybe I got luck and got a no-fail unit?

I have been reading about what settings are required to OC my 1055T to 4ghz, and I'll have to bump up my voltage. Hopefully that won't take me over the top. Crossing fingers...

Glendor...

 

[Glendor]

Or...

What single card (AMD or nVidia) would be an upgrade to my current SLI setup? I've been scouring the reviews, but I haven't yet found a "single X" vs. GTX 275oc SLI comparison. I'm probably just overlooking it, but if someone could save me a lot of time with a recommendation or link, I would appreciate it.

Glendor...

 

[lsv]

The 275 SLI is about as fast as a single 480 GTX.

 

[Martimus]

Okay, I was only 'thinking about' trying triple SLI, but I'm convenienced that it may not be worth it, both peformance wise, and because I would need to upgrade my PSU. Instead, I'll probably throw in an older video card for dedicated PhysX processing instead; something that doesn't require additional power, like a 9500GT w/ passive cooling.

My Mushkin PSU has been doing so well, I hate to replace it. I reran all my benchmarks last night, and the temp output at the PSU fan never seemed to increase during this stress test. Maybe I got luck and got a no-fail unit?

I have been reading about what settings are required to OC my 1055T to 4ghz, and I'll have to bump up my voltage. Hopefully that won't take me over the top. Crossing fingers...

Glendor...

I wouldn't even continue to use the PSU you have for the setup you describe. It may work like a champ right now, but the more you run it at its designed limit the more likely it will fail. When it does fail, you will lose a large portion of the components in your system. A PSU failure can be quite catastrophic (I have seen that puff of magic smoke a few times, and each time it took at least 1 major component with it.)

 

[Glendor]

I wouldn't even continue to use the PSU you have for the setup you describe. It may work like a champ right now, but the more you run it at its designed limit the more likely it will fail. When it does fail, you will lose a large portion of the components in your system. A PSU failure can be quite catastrophic (I have seen that puff of magic smoke a few times, and each time it took at least 1 major component with it.)

I've seen the Magic Smoke get out of a radio once, but never had that happen to a PSU. Either you're having really bad luck, or I'm having really good luck; maybe both. <knocks on wood>

I would have thought that there would be a significant increase in the exhaust air temp on an overworked PSU. Mine flows cooler than my wife's off-the-shelf Dell. It's just a few degrees higher than ambient (which aint that cool here in Houston). Based on the comments in this thread, I'm going to postpone the additional graphics card. I'm also not going to add a pair of 1TB drives I was planning on, but I'm not sure if I'll replace the PSU yet. It works too well, looks good (mirror finish), and would require over an hour of cable management to remove/install.

Glendor...