Widescreen Gaming Forum

Lo all.
just thought i would share an intresting issue i had.
I am running 3 480gtx's in sli and surround at 6100x1200 with a 980x cpu and performance was very good. I can run bad company 2 at mostly medium to high settings with aa and af set to 2(any higher starts to kill the framerate) and framerate stays at 60, but drops to about 45 to 60 if i up everything to high.
I was having a issue with the pc randomly rebooting after a while, so figured it was the psu(cosair 1200watt) so i added a spare 1000 watt psu and have the second psu running 2 of the 480's. Now the reboots are gone, but suprisingly my pc performance has also improved with the additional power.

I can now run bad company 2 with everything set to high and aa and af set to 8 and the framerate is locked at 60. It would seem that the system was been starved for power.
I have always said that a good psu is a must for system stability, but i didnt think it could improve performance as well on high power rigs.

That's completely interesting. When I build my next build, I'll make sure to get a decent power supply.

I could tell something was wrong when you said you used medium to high settings and were getting between 45 to 60 frames. My single 5850 averages 40 fps @5916x1080 all settings maxed with no aa and hbao off.

Good tip on the psu

how do you "power on" the second psu ?

You can get adaptor cables that basically join the second PSU's ATX connector to the first so that pushing the power button gets both to fire up. My Silverstone TJ07 came with one (no idea where it is ATM, though. :()

Or you can ghetto mod it. ;) http://www.overclock.net/power-supplies/14455-multiple-power-supply-guide.html

thanks i din´t know about the adapter

but i had to test a couple of psu´s some years back and they teach me to use an bobbypin to start them up
this would be a bit inconvenient for an 24/7 setup :D

I would of thought that AX1200 could of handled it, a heavily overclocked SLI (2) 480 setup with a 980 draws around 950w from the wall, I might ask how much other stuff you have hanging on the 12v rail of the PSU, but I am amazed it didn't cope!

I can see it yeah.

I hooked up a power-meter to my rig (980x and 3 480's) when gaming.



(this is with the video cards at stock.)

That rig would break me from the power bill and turn my bedroom into a sauna! My single 5870 can raise my room over 10 degree's easy with a couple of hours gaming.

The 1200 is on its limit , and it will be ok for up to an hour at first, then it will start to reboot more and more often under full load, and the psu it too hot to touch by then. so it does seem like its simply drawing to much power. and it will be ok for a while if i allow the psu to cool down again, i do plan to keep the second psu hooked up all the time to distribute the load more evenly.
the heat isnt a factor as i have the rig water cooled and cpu or gpu temps would be lucky to ever hit 50 celsius even under full load

Doesn't matter how you've got it cooled - heat dump into the air is still the same (actually, it should be better with watercooling) so the room would get just as hot as fast or faster with watercooling. Watercooling isn't this magical thing that makes things draw less energy or get more efficient - it's just more effective at removing heat from the heat-producing thing than air cooling.

Also, if you're reading that at the wall, that 1134w figure isn't actually 66w away from maxing the PSU, as you need to take into account PSU inefficiencies.

It's still rather too close for my liking in terms of power draw, though. ;)

It's still rather too close for my liking in terms of power draw, though. ;)

1134/1200, thats too close imo too.

Sorry, but it is not 1134/1200. It's obviously too much for the PSU sustained, but it's 1134w at the wall - which includes whatever inefficiencies the PSU has. If the PSU was 100% efficient, yes, it'd be 1134/1200. But it's not. It's probably at best 90% efficient. :)

Strange stuff though, CoolMan. My cards are wayyy hotter than my PSU during & right after load. I blame your unit. :?
A secondary/supplemental PSU can indeed be a great help in solving instability and/or overheating issues, though. I still have one of these somewhere...

scavv's right, though; does sound like it's a faulty PSU. I know for a fact (experience) that even when company's say they test every unit, sometimes a bad one manages to sneak through. :(

You can get adaptor cables that basically join the second PSU's ATX connector to the first so that pushing the power button gets both to fire up. My Silverstone TJ07 came with one (no idea where it is ATM, though. :()

Or you can ghetto mod it. ;) http://www.overclock.net/power-supplies/14455-multiple-power-supply-guide.html

Hm. Didn't know they made adapters for that. I thought the only way to do this was by "ghetto modding" it, but an adapter sounds much easier.. and safer.

Doesn't matter how you've got it cooled - heat dump into the air is still the same (actually, it should be better with watercooling) so the room would get just as hot as fast or faster with watercooling. Watercooling isn't this magical thing that makes things draw less energy or get more efficient - it's just more effective at removing heat from the heat-producing thing than air cooling.

Just to pick a thermodynamics bone, do you think the relatively large volume of coolant in a watercooled system represents a rather large thermal mass which absorbs much more heat energy per degree rise in coolant temp? In effect, the mass of coolant in the tubes, waterblocks, reservoir, and radiator is a far deeper heatsink than the thinly finned air-cooled heat exchangers attached to standard air coolers, blown by fans to immediately conduct heat into the airstream, out of the case, and into the room.

In other words, water-cooling is more effective at absorbing and storing heat from the heat-producing thing than air cooling. Next, it takes more energy and far longer for the liquid to heat up. Thus, heating of the room takes far longer while the PC parts take much longer to heat the liquid coolant to temps far enough above ambient for the radiators to begin transfering the excess to the airstream.

It's similar to the way it takes time in winter from a cold start for a car engine to heat the liquid coolant enough for the heater to blow warm air, all while you sit there shivering and rubbing your cold hands together pleading, "c'mon, heat, C'MON HEAT!!"

Cheers :D

[quote]Doesn't matter how you've got it cooled - heat dump into the air is still the same (actually, it should be better with watercooling) so the room would get just as hot as fast or faster with watercooling. Watercooling isn't this magical thing that makes things draw less energy or get more efficient - it's just more effective at removing heat from the heat-producing thing than air cooling.

Just to pick a thermodynamics bone, do you think the relatively large volume of coolant in a watercooled system represents a rather large thermal mass which absorbs much more heat energy per degree rise in coolant temp? In effect, the mass of coolant in the tubes, waterblocks, reservoir, and radiator is a far deeper heatsink than the thinly finned air-cooled heat exchangers attached to standard air coolers, blown by fans to immediately conduct heat into the airstream, out of the case, and into the room.

In other words, water-cooling is more effective at absorbing and storing heat from the heat-producing thing than air cooling. Next, it takes more energy and far longer for the liquid to heat up. Thus, heating of the room takes far longer while the PC parts take much longer to heat the liquid coolant to temps far enough above ambient for the radiators to begin transfering the excess to the airstream.

It's similar to the way it takes time in winter from a cold start for a car engine to heat the liquid coolant enough for the heater to blow warm air, all while you sit there shivering and rubbing your cold hands together pleading, "c'mon, heat, C'MON HEAT!!"

Cheers :D

Nah, the amount of heat the loop holds, while it can be warm, it only buffers a little before the rad starts pumping warm air into the room.

Water cooling is exactly the same as air cooling. Its still air cooled.

Yes a water block can wick away heat faster than a regular air cooled heatsink, however the ability of it to do that is based on the temperature of the water, and the water is cooled by guess what? A regular air cooler just like the cpu normally is.

The water cooling's real advantage is nothing more than the fact that the radiator it uses to cool itself is larger and has more surface area than the cpu's air cooler does and also its usually located outside of the case in many setups allowing cooler air to be run through.

When using a high end cooler like a thermalright ultra 120 I noticed no real difference between my high end water cooling and my high end air cooling. Being able to keep the cpu 40c instead of 45c is great and all but actually didnt make for a better overclock or anything.

Also the room is just as hot ether way because heat is just transferred into the air one way or another be it from the water to the radiator, or directly from the cpu air cooler.


The other advantage of water is really that it can cool the gpu's and stuff too while there is not a large market for high performance air coolers for video cards and the few there are wont work well in multi card setups.

Once you go down that road though your dumping a lot of heat into the water loop and you can start to adversely effect the temperature of other things on the loop if your radiators are not large enough and getting enough air.

Overall for me I wont go back to water, it was a hassle to deal with, made upgrading and working on the system more difficult and I gained not a bit of performance out of it. It did make for some pretty pictures though. These days I dont even have an open window case anymore I went away from flashy a few years ago and now like just sleek and modern.

Noted. Thanks for the info.

I use the Corsair H50 CPU cooler in my builds, more for noise reduction than for increased cooling capacity. I tend not to overclock.