3 Way SLi heat investigation

[Rollo]

I've read a lot of speculation about 3 way SLi being a candidate for heat issues by people not using it recently.

In light of this, I decided to build a 3 way system in my old, non 3 Way SLi certified case and see what happened before investing in one of the new certified boxes.

Note: I'm currently testing another machine with a 3-way certified CoolerMaster Cosmos case, and I can safely say one of these is probably in my future. The Cosmos makes my old XaserIII look it's age, and runs very cool and quiet.

The good people at EVGA were kind enough to replace my 680i with a 780i.

This was an easy switch, booted up fine without format/reinstall. I like the layout of the 780i, installation was easy, and I love the new ESA system manager they launched along with this board.

I formatted after and switched to Vista 64 Ultimate to accomodate the two additional sticks of OCz PC8500 SLi Certified RAM I purchased. I also purchased an Intel QX6700 for this build.

To power the beast, I decided to blaze a trail and go with a non 3 way certified NZXT Precise 1200W PSU.

I went with the NZXT primarily because of it's 10A input power rating, and the fact my computer is on a 15A circuit breaker. (my 1000W PC Power and Cooling was rated at 15A input, and I never had a problem, but I thought I'd try the NZXT)
This PSU is modular, and has 2 X 6+2, 2 X 6, and a 1 X 6 split to 2 for physics PCIE. I'm running two of the GTXs with one dedicated 6 pin, and the split physics line as the second on each on the assumption 1.5 dedicated lines per GTX is better than 1 split line powering one.
This PSU is also standard size, so it should fit in almost any case you would put 3 Way SLi in.

It all fired up fine, ran the Orthos stability test at stock fine, and the nTune stability test fine as well.

I can now say unequivocally the heat speculation is totally a myth

I fired up the system monitor, ran UT3 in a window for well over an hour, and my GPU temps stayed at a steady 84C-86C.

This is compared with 79C-81C with 8800GTX SLi, in my opinion, more than an acceptable trade off.

I should note at this point I had modded my Xaser III last month by replacing the plexiglass side window with a couple layers of screen to maximize airflow, so don't expect these temps on a stock Xaser III if you have one.

I would also note that many performance cases now have more open side ventilation, and that a friend at NVIDIA has been using the CoolerMaster Cosmos case without mofication to achieve similar temperatures.

[Fraz]

But.... can you play Crysis?

[Rollo]

But.... can you play Crysis?

Haven't re-loaded it yet, but I'd guess better than any other rig on the planet.

And not as well as UT2004.

Crysis is one of those titles that a. we're waiting for a performance enhancing patch for all cards on b. is a forward thinking, hugely taxing engine for any graphics solution.

As my monitor is 19X12, I'm guessing I'll be opting for all "High" settings, and perhaps 4XAA:
bit-tech.net | First Look: Nvidia 3-way SLI on nForce 680i - Crysis

Crysis is only one game (although it's an excellent game) and 3 way Sli will allow me to play others at higher levels of AA than any other solution.

IMO- greater image quality is what you get high end parts for.

[Fraz]

You might find this interesting:

AnandTech: NVIDIA's 3-way SLI: Can we finally play Crysis?

The scaling plot on the third page shows how well certain games scale to 3 cards. Bioshock, UT3 and COD4 seem to do particularly well.

[Rollo]

You might find this interesting:

AnandTech: NVIDIA's 3-way SLI: Can we finally play Crysis?

The scaling plot on the third page shows how well certain games scale to 3 cards. Bioshock, UT3 and COD4 seem to do particularly well.

I've read the AT review, and have nothing but respect for them.

Some other sites reviewing 3 Way SLi looked for what differentiates the solution from dual SLi also.

Running "25X16 4X16X" at COD4 getting 100fps instead of 78fps is well and good, but it's also worth knowing you can run COD4 at 25X16 8X16X and get 77pfs average rather than 60fps average with dual SLi:
NVIDIA 3-Way SLI Performance Preview

HotHardware also noticed this:
NVIDIA 3-Way SLI Performance Preview - HotHardware

It's a recurring theme that just doesn't change. 3-Way SLI isn't helpful if you're running 1920X1200 resolution with anything less than 8X AA, or better still, 2560X1600 resolution with 4X AA or higher.

What I liked about running Quad SLi last summer was that it gave me the ability to run most games at either 8XAA or 16XAA at 19X12, which looks really nice.

I see that as the main value of solutions like this- the ability to achieve higher image quality at higher resolutions.

BTW- I disagree with HotHardware on the "only 8X AA at 19X12" but for the most part it's true.