GPU Pair -- Serial or Parallel

[EazzyTarget]

Hey guys, first post here... been reading a bit and think I've done okay so far with my parts... but wondered if the parallel path through my GPU blocks is going the wrong way.

I've designed and put together most of the following water cooling in my Cosmos 1000 case:

Resevoir

Pump

CPU

Rad 1 (Black Ice GT-XFlow 120)

T-Splitter

2x8800 Ultra GPU's in Parallel

T-Splitter

Rad 2 (Black Ice Pro 3)

​

My concern, from my reading, is that the Swiftec Stealth GPU blocks in parallel may have different pressures and that the water would circulate through one more than the other... creating a temerature problem in the one with less flow.

How are you guys handling 2xSLI (or more) in your cooling loops?

-EazzyTarget

 

[rrjwilson]

I am currently running in series and i am getting serious temp issues. I have even had to knock the CPU back again from 3.7 to 3.0 because of heat created and summer being here.

Parallel splits the thermal loading and increases thermal transfer because of higher dT gradient. I believe your worries are unfounded as the pressur drop difference between identical blocks should be almost insignificant and as the rad is a partial reservoir as not all water moves through it at the same speed this will only help your situation.

May i ask what CPU you have?

I have a q6600 and 8800GTX in SLi and with one PA120.3 its toasty so if yours is quad core or even dual with slight OC I'm not sure you will get a cool running setup with those rads.

 

[EazzyTarget]

May i ask what CPU you have?

Sure, I have the QX9650 -- but am not really planning to OC (famous last words).

My biggest thing was the noise from fans and the incredible heat generated by the 8800. I ran in SLI on air for a short while but the MB kept shutting down with an overtemp warning.

I will get the last of my equipment (Rad 120.1) today and can finish my loop, but I leak tested everything (else) last night for just over 2 hours and the loop idles at 103 degrees farenheit (without fans on 120.3 radiator).

So I am optimistic that *with* fans and the second smaller radiator (after the CPU) that I can get 10 degrees or so cooler at idle.

I guess only time will tell!

-EazzyTarget

 

[Toxcity]

Running without fans on your Rads?

 

[EazzyTarget]

Running without fans on your Rads?

Yeah, the screws I bought were too short so I couldn't mount them last night as I had planned and the local hardware store was closed.

So, what started as a leak test / flush, turned into a "how warm will it run" test (no RAM, Hard Drives, or Audio card in the system).

-EazzyTarget

Ps. I picked up longer screws on the way into the office this morning and will mount everything tonight

 

[Toxcity]

Bet it got warm?

Good luck on the mounting. Do you think you could post some images of the finished build?

 

[EazzyTarget]

Bet it got warm?

Good luck on the mounting. Do you think you could post some images of the finished build?

Well, I had the loop cycling into/out of a large pitcher so it was a lot of water to heat up which -- now that I think about it -- is probably why it only got to 103 degrees... :whack:

I will definitely post some pics when all done (later tonight or tomorrow night)!

-EazzyTarget

 

[EazzyTarget]

Here are a couple of pictures for you of my finished mod.

From power off to power on was just under a week of "spare time" to complete.

Which I thought was pretty good, but my my eight year old son thought was about 6 days too many since I had taken over the home theatre and he couldn't play his video games for a whole week!!!

Anyhow, everything leak tested great until I put the side panel back on... the resevoir inlet was a little loose and the side panel flexed the hose enough to create a leak...

Other than that, she seems to be working great! Pulled a 17,000+ 3DMark'06 upon power up... which I thought was GREAT.

-EazzyTarget

 

[agentx]

so wat kind of temps do u get now. idk if this is true but wouldnt it have been better to use dual core rads instead of single core as they dissapate more heat faster.

 

[EazzyTarget]

so wat kind of temps do u get now. idk if this is true but wouldnt it have been better to use dual core rads instead of single core as they dissapate more heat faster.

GPU's temps are within a degree of each other at 65C when running Crysis at 1920x1200 high everything.

The CPU's cooling delta was not as good, I've seen max temps hit 54C when fully loaded -- only slightly better than what I had using air!

I don't know enough to know what the difference in the radiators would be, the HL BlackIce Pro III was described as a "2 Pass" radiator. Is that the same as dual core... I am guessing not.

Is there a radiator I could have used instead that would cool the 65C degree water coming out of the video cards better? I would love to get the CPU cooler and the NB/SB would like some water too... but I can't imagine adding them to the loop.

Thanks in advance for any feedback.

-EazzyTarget

 

[agentx]

i just finished a build using 2 of these : http://www.acousticpc.com/black_ice_xtream_II_radiator.html . one has fans on it the other doesnt (dont ask long story) im cooling nb, sb, cpu, gfx card, and one mosfet (other on air). and my temps are pretty nice (i the low 90s). the dual core should (cant say for sure) nock about 10 degrees off ur temps depending on ur room temp as they act as heatsinks for the liquid.

 

[EazzyTarget]

i just finished a build using 2 of these : http://www.acousticpc.com/black_ice_xtream_II_radiator.html . one has fans on it the other doesnt (dont ask long story) im cooling nb, sb, cpu, gfx card, and one mosfet (other on air). and my temps are pretty nice (i the low 90s). the dual core should (cant say for sure) nock about 10 degrees off ur temps depending on ur room temp as they act as heatsinks for the liquid.

Yeah, that looks like a next gen version of what I used (though I used the 3x120 version). The one I wanted was the GT Stealth with X-Flow but it was "Out of Stock" when I was doing my build with no delivery date.

I didn't realize that Gen1 to Gen2 would make that big of a difference, 10 degrees is huge!

I notices HWLabs site shows a GTX Extreme model... http://www.hwlabs.com/gen2/gtx/gtx360.htm that would probably be my best bet.

Hmm... it has only been a month and now I am considering taking my water cooling loop apart to re-do it... my wife will love that!

-EazzyTarget

 

[agentx]

well wat the wife doesnt know wont hurt u lol. but ya they're bigger so theres more metal to soak up more heat i got those though b/c i was low on cash but didnt want to scimp on cooling. but if u want cooling power for cheap try these (maybe 4 or 5 in series out side ur case) http://www.performance-pcs.com/cata...ge=product_info&cPath=59_310&products_id=4515 big bad liquid to metal heap sinks lol cheers.

 

[Frosty]

Your setup looks great. A lot like the one I was planning on building. That being said, I have a few questoins for you.

1. How did you mount a 360mm rad in a cosmos 1000? It only comes with drilled ports for two 120s unlike the three 120s in the cosmos s.
   
2. If you modified the case to mount it what did you have to do?
   
3. Is there anything special about the T line that you have the fill port hooked into? IE is there anything other than gravity and a plug holding in the liquid?
   
4. How loud is it?
   
5. What size tube and barb did you use?
   

I'm going to have this beast hooked up to a 47inch LCD to double as a gaming rig and HTPC and don't want it to drown out the sound.

Thanks.

 

[agentx]

well unless u have the volume set to low on ur sound system i doubt that the loop will drown out the sound so u dont have to worry about that.

 

[EazzyTarget]

Your setup looks great. A lot like the one I was planning on building. That being said, I have a few questoins for you.

1. How did you mount a 360mm rad in a cosmos 1000? It only comes with drilled ports for two 120s unlike the three 120s in the cosmos s.
   
2. If you modified the case to mount it what did you have to do?
   
3. Is there anything special about the T line that you have the fill port hooked into? IE is there anything other than gravity and a plug holding in the liquid?
   
4. How loud is it?
   
5. What size tube and barb did you use?
   

I'm going to have this beast hooked up to a 47inch LCD to double as a gaming rig and HTPC and don't want it to drown out the sound.

Thanks.

Thanks Frosty!

Happy to provide answers.

How did you mount a 360mm rad in a cosmos 1000? It only comes with drilled ports for two 120s unlike the three 120s in the cosmos s.

(And,) If you modified the case to mount it what did you have to do?

Yes, two minor case mods were required.

First, to mount the 360 on the top, I used a hole cutting bit to allow airflow for the third fan in the top of the case. (I can provide a picture if you would like)

Second, to mount the rear fan and radiator I removed the ventilated fan guard on the rear of the case where the CPU is normally vented. This was a convex vent and prevented flush mounting of the radiator when I tried to mount directly to the rear. Wire clippers did the job!

Is there anything special about the T line that you have the fill port hooked into? IE is there anything other than gravity and a plug holding in the liquid?

No... truth be told I added that as an after-thought and it is only there so I can pressurize (with air) the line to drain the system if/when I need to... I disconnect the lower hose on the rear radiator and apply air pressure to the "fill port". Liquid drains out nicely (with only some minor bubbles left).

How loud is it?

Very quiet. The only fan I hear is from the PS -- the fans that came with the Cosmos are very quiet (amazingly). I wouldn't have any concerns in your environment.

What size tube and barb did you use?

Everything is 1/2" ID. Only word of caution is be careful that the O-Ring seals are perfectly centered and the seal is 100% when you tighten down the screw in barbs!!! Even a minor "off center" turns into a leak when you tighten them down all the way... = : (

-EazzyTarget

 

[Frosty]

Thanks for the info. Just knowing I can fit a tripple 120 rad in there helps a lot. I'm trying to research all this from Iraq to build the rig when I get home, and its hard when you only have pictures and reviews to go on. Some people fritter their hard earned deployment income on hot rod cars while I build uber gaming rigs. Your tax payer dollars at work!

 

[EazzyTarget]

Thanks for the info. Just knowing I can fit a tripple 120 rad in there helps a lot. I'm trying to research all this from Iraq to build the rig when I get home, and its hard when you only have pictures and reviews to go on. Some people fritter their hard earned deployment income on hot rod cars while I build uber gaming rigs. Your tax payer dollars at work!

First of all, thank you for your service. Know that I appreciate the sacrifices that you and the rest of our troops are making for your country. :hands:

If you have any other questions as you tear into your Cosmos 1000, either post on this thread or feel free to PM me... my pleasure to help.

-EazzyTarget