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Critique my cooling design

D

dsiglin

n00b
Joined
Jan 29, 2013
Messages
21
Hey guys, long time lurker first time poster. Im in the throes of a G5 Powermac modification (my first case mod ever) and let's just say I'm having to be very creative to achieve the look I want. So I have come up with a cooling solution but I am not very familiar with cooling theory and would love some feedback. I'm attaching a file that shows the actual computer (with paper mockups of components and next to it an illustration that shows more clearly what I have in mind. I realize the location of components is strange but there is a method to my madness. Thanks in advance and please feel free to ask any question.

g5build0127b.jpg
 
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So you just bought a G5 case with the intent of modifying for modern PC components? BTW, I love that case design.

Moreover, there's not that much "theory" behind case cooling.. it's more practice. Just generally a few rules of thumb:
- More intake flow than exhaust... positive air pressure keeps dust out
- Do not introduce 3D airflow (leave out side-panel intakes)
- Look for "air channels"... make sure there is a channel going to every major heat component (CPU, GPU, and hard drive stack)
 
Yeah got it for around $50 including shipping. Most G5 mods look like hack jobs. I want to make one that retains the elegance and simplicity of the original G5. I'll be doing a worklog and releasing all schematics/templates for fabricating new case parts so anyone can build their own. I'm also going to try and make it easy to assemble and disassemble with modular components.

Re: airflow - Well I have the last two points down. The original G5 was phenomenal with creating channels of airflow and I've followed their lead with slight modifications.

The first point though about positive air flow - it seems people are split. Some people swear by negative and others swear by positive. I read that negative means less dust but then someone says "no it makes more dust build up". :confused:
 
No reason that shouldn't work pretty damn well IMHO.

Where'd you get a G5 case for 50$!
 
I got it off ebay, they seem to be going cheap right now. I literally was the only bidder. It's a bit dicey though as it's hard to tell how much scratching the cases have. I usually message the seller and have them describe any areas I'm not sure about.

What do you think about the closeness of the video card and the PSU? I know they are drawing air from different airflow areas but it seems like the PSU could draw warm air from off the back of the video card. I was thinking about making a back shield of sorts for the video card to keep warm air movement horizontal. The clearance between the PSU and video card is 1.5"-2"

I had an earlier design that had the video card facing toward the PSU so both the PSU and the video card drew cool air from the same area but their closeness made me nervous that would cause both to run hot. To achieve the video card facing down I'm having to use a riser cable.
 
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i think your GPU is the wrong way in the schematic, the motherboard will be upside down, as well as the GPU, so it would be competing to take air from the PSU, BUT there is probably enough space in between that it shoulding be a problem.
 
Bigted you are right, it is the wrong way around. I bought one of these PCI-E x16 riser cables so I can flip it whichever way I want. Plus I can move the motherboard back from the G5's original IO ports a bit and still have the video card attached to the PCI brackets.
 
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dsiglin said:
I got it off ebay, they seem to be going cheap right now. I literally was the only bidder. It's a bit dicey though as it's hard to tell how much scratching the cases have. I usually message the seller and have them describe any areas I'm not sure about.

What do you think about the closeness of the video card and the PSU? I know they are drawing air from different airflow areas but it seems like the PSU could draw warm air from off the back of the video card. I was thinking about making a back shield of sorts for the video card to keep warm air movement horizontal. The clearance between the PSU and video card is 1.5"-2"

I had an earlier design that had the video card facing toward the PSU so both the PSU and the video card drew cool air from the same area but their closeness made me nervous that would cause both to run hot. To achieve the video card facing down I'm having to use a riser cable.
Click to expand...

Well, you can do one of a few things. If you're good with machining, you can cut a 120mm hole at at the top for the PSU intake fan. Install a fan filter and a fan grill. Of course, it probably won't look as good.

Another option is to use a GPU with a blower fan (think reference design). These are meant to vent as much air out of the case as possible, as opposed to most aftermarket solutions which just swirl the air around inside the case. It may be a bit noisier, but most modern blowers aren't too loud.

Thirdly, you can buy a cheap AIO water cooler (zalman on sale for $40 right now), and a $10 adapter to watercool the GPU. You should be able to mount it where that blue block is, left of the GPU in the schematic (I'm assuming that's a fan).

I think it should be fine. If you use a powerful front-top intake, it should give you enough air to supply both the PSU and the GPU.

Positive airflow is definitely preferable to negative airflow. With positive airflow, air is pushed out of all openings, preventing dust from getting in. In negative airflow, air is being sucked in through all openings, allowing dust to get in.
 
Some very good ideas Eureka! I hadn't considered water cooling the GPU. I am going to water cool the CPU since it gives me flexibility for where the CPU heat is dissipated. However with the current setup I have the fan to the left of the GPU is blowing air in for the PSU. So I'm guessing a radiator there would just feed the PSU warm air. Speaking of that fan, it is 80mm. I haven't actually bought that fan yet so if you have suggestion for 80mm fan that's quiet but has good CFM I'd appreciate it. I'm hoping to make the case whisper quiet. It's probably going to be a quixotic task given the entire front and back are perforated aluminum.

EDIT: somehow I missed you were talking about the fan feeding air to the PSU and not the fan on the bottom right. Edited my reply.
 
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It might be a stretch with the tubing, but you could place the GPU radiator at the bottom right, and have it as an intake.

How good are you with machining? At this point, it might be better to build a bracket for a 240mm radiator, and just do a custom water loop. The most silent you'll get your PC to be, and you won't have to worry about airflow.
 
I have a friend with a machine shop and I'll do whatever it takes to build this case to the way I want it, even if I have to take a hiatus to learn machining. I want to keep cost down but I hear Rasa has some complete systems for $130? One reason I want to keep cost down is so others, even those on a budget, can follow the design and build their own G5. I'm making some design choices to keep the build fairly noob friendly (I am one) to encourage better adoption of it.
 
dsiglin said:
I have a friend with a machine shop and I'll do whatever it takes to build this case to the way I want it, even if I have to take a hiatus to learn machining. I want to keep cost down but I hear Rasa has some complete systems for $130? One reason I want to keep cost down is so others, even those on a budget, can follow the design and build their own G5. I'm making some design choices to keep the build fairly noob friendly (I am one) to encourage better adoption of it.
Click to expand...

If you can machine, costs will be relatively cheap. If you can learn CAD, and your friend has a CNC, then all you have to do is draw out your designs in the computer and send it over.
 
Sorry if I am confused, but wouldn't the main cost for a custom liquid cooling system be the pump and other parts, not the mounting bracket for a radiator?

I'm a graphic designer by training and I found out Illustrator can export to CAD files so I can design for CAD without having to buy or learn it. Oh happy day.
 
dsiglin said:
Bigted you are right, it is the wrong way around. I bought one of these PCI-E x16 riser cables so I can flip it whichever way I want. Plus I can move the motherboard back from the G5's original IO ports a bit and still have the video card attached to the PCI brackets.
Click to expand...

that cable is 7.5 inches long which will give you a lot of options, but i don't know if you'll be able to flip it all the way around. sounds like you might be going liquid cooling on it though, so liquid would make a huge difference as far as where/how you mount the gfx card
 
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dsiglin said:
Sorry if I am confused, but wouldn't the main cost for a custom liquid cooling system be the pump and other parts, not the mounting bracket for a radiator?
Click to expand...

Well, yes. That's the price you pay for optimal cooling and silence. With air cooling, noise and performance are related.

Quite honestly, you could just do it the way you have it in your original schematic. I think it will be enough as is to keep your system running
 
Most likely I will just stick with an AIO solution. However your idea of liquid cooling the GPU made me realize I could use a low profile air cooler for CPU and run an AIO liquid cooler from the GPU to the rear fan assembly.
 
Hey phnguyen90 if one of those is a the late 2005 version I'll buy one from you :)

btw I probably should have mentioned my componets - PSU is a Seasonic X750 and GPU is a Galaxy 660Ti GC. GPU cools by blowing down air onto the GPU so no directional blow of air out the back of the case. :/
 
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dsiglin said:
Hey phnguyen90 if one of those is a the late 2005 version I'll buy one from you :)

btw I probably should have mentioned my componets - PSU is a Seasonic X750 and GPU is a Galaxy 660Ti GC. GPU cools by blowing down air onto the GPU so no directional blow of air out the back of the case. :/
Click to expand...

I would actually say just try it with just air first and watch your temperatures. Then decide if you need to go the whole nine yards.
 
Thanks all for the advice and discussion. I'm going to hopefully do a test install soon. I need to fabricate a removable motherboard tray first and then should be straightforward from there.

I haven't bought any fans yet so I need to do some research on fans with good CFM and air pressure yet quiet.
 
dsiglin said:
Hey phnguyen90 if one of those is a the late 2005 version I'll buy one from you :)

btw I probably should have mentioned my componets - PSU is a Seasonic X750 and GPU is a Galaxy 660Ti GC. GPU cools by blowing down air onto the GPU so no directional blow of air out the back of the case. :/
Click to expand...

:D I am not the seller hehe my car is too small for 10 G5
 
You should be able to get this kit from XSPC for around 150$ :
XSPC Raystorm Kit RS240
It comes with a pump/res combo and it works like a hot damn, I'm currently running the RX240, which is just a thicker rad, that I picked up for 180$. Just don't use the tubing the kit comes with, it turns yellow, purchase quality tube - its cheap.

To cool your GPU you could use something like a Swiftech MCW82 - 60$
Link
If you do so you should pick up some VGA RAM Heatsinks which usually come in a bag of 8 for 8-15$.
 
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