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I can't find an answer to a couple of seemingly simple questions. They are closely related though so I'll ask them all here. They are partially gaming related, but I've posted them here instead of because it's mostly hardware related.

I've just bought a new PC - here is my setup:

  • Intel® Core™i7 Processor Extreme Edition i7-990X (3.46GHz) 6.4GTs/12MB Cache
  • ASUS® RAMPAGE III EXTREME: 3-Way SLI & CrossFireX, SATA 6.0GB/s, USB 3.0
  • 2x 1536MB NVIDIA GEFORCE GTX580 - 2 DVI,mHDMI - DirectX® 11, 3D Vision Ready
  • 2x 120GB OCZ VERTEX 2 SATA II 2.5" SSD (upto 285MB/sR | 275MB/sW)
  • 2x 500GB SERIAL ATA 3-Gb/s HARD DRIVE WITH 8MB CACHE (7,200rpm)
  • RAID 0 (STRIPED VOLUME - 2 x same size & model HDD / SSD)
  • 2x BenQ G2400W 24" TFT Monitor 1920 x 1200 250 cd/m2 5ms
  • Windows 7 Ultimate, 64-bit

In the NVIDIA control panel, the driver version is stated as 266.58. DirectX 11.0 is installed

On to the questions:

  • For SLI, I have plugged both monitors into the first card using DVI - is that correct? I could use HDMI as there are 2 HDMI ports on each card and my monitors have HDMI inputs as well.
  • Some games (e.g. GTA IV) only report seeing 1536MB of graphics memory - is this because I am running SLI?
  • Do I have to disable the second monitor before starting a game for SLI to work properly?
  • Should I enable PHYSX - presumably it would be as if it were disabled if it's not being used at any particular time?
  • My assumption was that with a PC of this spec, I should be able to run the vast majority of games with all of the settings maxed out. This does seem to be the case for a while, but after a while some games cause the PC to reboot - I think this may be the gfx cards overheating but how can I find out?
  • Even with the liquid cooling, the PC is very loud. When starting most games, the fans will increase in speed (there seem to be plenty of them) and it's not that they drown out the sound but it's certainly loud enough to be distracting.

I didn't build this system, it was custom-built by a reputable company who specialises in high-end systems and the various parts and configuration was checked.

Can anybody help with some/all of these issues?


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That computer is outdated and underpowered anyway just build a new one. – Not Kyle stop stalking me Mar 23 '11 at 13:32
In all seriousness start out by monitoring your temps see if it gets particularly hot before it reboots. – Not Kyle stop stalking me Mar 23 '11 at 13:40
lol @ Kyle. That said, geez, are you ONLY going to be gaming on this thing? That's like using a jackhammer to hang pictures on the wall. >.< This thing is GOING to be loud, though, in that case. – Shinrai Mar 23 '11 at 14:18
point taken. first card is 72°C when just idle desktop after being on for a few hours, no gaming - is that reasonable? – enashnash Mar 23 '11 at 15:41

Slightly shares memory between the cards. So you only see 'half' the memory. I can't remember exactly why that is, but there you go.

If fan noise bothers you, replace them with some quieter fans. Just make sure you get the right size.

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Answers to my questions that I've discovered:

  • I plugged one monitor into each card rather than both into one, this works much better.
  • It does seem as if I should see half the total memory when running SLI, although I've yet to find the reason.
  • I don't have to disable the second monitor for SLI to work.
  • Reading around, it seems PhysX only uses resources when the game actually requires the feature.
  • Plugging one monitor into each card has drastically lowered the temperatures of the cards. The one that is running SLI still gets up to 100°C, but people have stated that this is normal.
  • The fans do get loud now that I have set it up this way, but only if playing a particularly graphics-intensive game.

Thanks for your help.

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