Silent Cube – Core i7, GTX 750Ti, PowerLogix

I recently completed another Mac Cube mod. My previous Cube mods have never been satisfactory as I wanted to achieve the following:

• Silent operation
• Powerful processor
• Dedicated graphics
• Large storage capacity

This mod is largely a prototype for whether I could achieve all of the above and has taken a long time to complete. Minor modifications are required to fit the core into the original Cube case.

The mod

The main idea of this mod is to keep the heat generated by the CPU and GPU to the centre of the Cube core. This was done by interlocking another aluminium heatsink in between the fins of the original heatsink. The original heatsink is used for the CPU and the additional heatsink used for the GPU.
A small 80x80x25mm PWM fan helps to vent the heat out.




Parts

Since I don’t have access to a CNC milling machine I chose parts that would do the job with minimal modifications out of the box, using a Dremel and drill. After much searching on eBay (and trial and error with various parts) I found the following worked well, pictures follow.

• Aluminium heatsink used for “LED and power IC transistor”. The size is 150mm x 150mm x 35mm with 18 fins and 7mm gap between fins.
• Streacom HT4 thermal riser.
• Two types of CPU mounting brackets. One is a complete kit with screws (cpucooler.cn) and the other is an adjustable bracket for LGA 775/1366/1156 (no brand).
• Custom built 32cm shielded Gen3.0 PCIE riser. Purchased from a Taiwan based eBay trader (http://www.ebay.com/usr/liheat48)
• Aluminium mounting block from a fanless VGA cooler kit. Came with adjustable mounts to fit most graphics cards.
• Proslim SATA cables from Akasa. These cables can be cut to length and are very thin – perfect for tight spaces.
• Noiseblocker BlackSilentPro 80mm x 15mm Ultra Silent PWM Fan.

I’ve only listed the main parts here.






Computer components

• Gigabyte GA-Z97N-WIFI
• Intel Core i7-4790S Haswell Quad-Core 3.2 GHz, 65W TDP
• Corsair Vengeance (2x8GB) DDR3 1866 MHz
• GTX 750 Ti 2GB (originally used GT 640 for this build but similar in terms of TDP, 60-65W)
• Panasonic UJ-265 Blu-ray Burner
• 4 x 2.5 inch drives. Currently using the following:2 x SanDisk 240GB (Extreme II and Ultra II)
• 2 x 2TB Seagate HDD (ST2000LM003 HN-M201RAD)
• PicoPSU-160-XT 160W
• Apple BCM94360CD and mini PCIe adapter card
• Xbox 360 205W power brick modded to use with PicoPSU (see http://www.instructables.com/id/the-Brick-PSU/)

The build

Heatsinks

CPU - The Streacom thermal riser is attached to the original heatsink by hex screws from behind the heatsink. The adjustable mount bracket (with adjusters for screws removed) is also attached to the Streamcom thermal riser with hex screws.





GPU - The aluminium LED heatsink is cut to the same length as the original heatsink and additional fins cut off with only 10 remaining. The aluminium mounting block from a fanless VGA cooler kit is attached to the LED heatsink from behind with hex screws. The graphics card is attached with plastic clips. The GPU is held in place with screws into the base of the cube’s existing air holes.







Drive cage





Blu-ray. The blu-ray drive uses the original DVD outer housing with some 3mm plexi-glass along the edges for support.

HDD and SSDs. The 2.5 inch drives attach to a tray made from 3mm plexi-glass, painted white. The screws are countersunk given space constraints. The two SSDs are to allow dual OSes (OS X and Windows on separate drives). The larger 2TB drives are for storage and backups.





The SATA data and power cables are cut to length and shown connected to the drives below.



Power supply and switch



The picoPSU is wired up according to minihack’s guide (http://www.tonymacx86.com/powermac-g4-cube/43924-cube-switch-modding.html)). The LED glows brighter when your finger is close to the switch, and less bright when the computer is on.

Completed build

Top view with the fan installed.



Other views of the build in the PowerLogix case.



Benchmarks

Geekbench 32 bit: 13594
Geekbench 64 bit: 16074

Temperatures

Idle:
CPU 42°C
GPU 26°C

Load:
CPU 82°C
GPU 61°C

I created a custom fan profile using HWMonitor. The fan speed is set to operate at 1000 RPM, which is inaudible, most of the time at 65°C and lower and only reaches maximum speed of 2500RPM above 75°C.

Further modifications
Some modification would be required to fit into the original Cube case.

Move the Wifi card using a mini PCIe extender cable. It is too close to the retractable handle.
Cut slots into the top of the GPU heatsink to match the original heatsink. This is needed to accommodate the metal brackets inside the original cube case.

Conclusion
I’m very happy with the mod and the computer set up. It achieves everything I wanted, although it hasn't been the simplest build.

MacAddict

MacAddict welcome to the forum and great job on this cube.

Thank you for sharing your project.

I can see that a lot of work went into the re-engineering to get all of the tech into the cube form factor. I have not seen a double heat sink done before. Your approach will most likely cause others to consider taking on a cube project.

Anyway I really appreciate the work that it takes to complete a project like this.

Good modding,
neil

Thanks neil.
I've benefitted a lot from others in these forums who have shared their experiences on cube builds - and many of my own mistakes!

My modding skills are gradually improving so hopefully others take on the challenge.

At some point, I may create a custom IO plate but it needs the right paint. I think I'm close with "Pactra Acrylic Pearl White" R/C paint. It's a cheap metallic paint and only a little lighter than the original.

In the meantime, there's some thermal testing to be done with the heatsink design in the original metal case.

MacAddict

Wow! I'm impressed. I particularly enjoy the heatsink risers and using the original heatsink in your build. Makes me want to tackle another cube build

I think the G4 Cube is one of the best cases Apple ever produced - way ahead of its time.

macaddict,

congratulations on a superb mod! I really liked the dual heatsink design

what did you use for the front Apple logo? Is it the original one from the stock case?

cheers
F

Yes, the Apple logo is from the original case.

This is exactly what I want my build to be you did a really nice job!
Do you think using a 35w i7 would allow this to be a passive computer?
I assume the 750ti is the best bang for TDP unless anyone has any other ideas

what is the longest gpu u think could fit in here?