This system has proved to be very reliable and exceeded my expectations for performance.
(Nov. 2017 update: The USB board in the front burned out for the second time and the company no longer makes the part. Bummer. Fortunately the Mobo wasn't damaged and the case has a separate USB3 port on the front.)
System specifications
Case: NoFan CS-60 mATX Mobo: Gigabyte GA-B75M-D3H CPU: Intel Pentium G2120 Graphics: SAPPHIRE Ultimate Radeon HD 6670 RAM: Crucial Technology 8gb (2x4) Pc3-12800 1600mhz Ddr3 Ballistix Cl9 Drives: 120 gb OCZ Vertex, 128GB Samsung SM841, Super Writemaster SATA DVD/RW PSU: SeaSonic SS-400FL2 CPU Cooler: stock Intel with Scythe Slipstream 120 Other cards: Syba ieee1394a-b PCI-X
Performance
iPlane9 and Flightgear flight simulators: smooth and responsive at max frame rates
Will run 2 Windows VMs in VirtualBox both doing updates, Firefox with a dozen or more tabs, Chromium with multiple tabs, Libreoffice with multiple documents open, and Thunderbird: switching between applications, mouse movement and typing are instantaneous; opening additional applications, e.g. gthumb to import pictures, is as fast as if nothing else were running. In other words, it'll do more things at once than I can keep track of.
Boots Ubuntu 14.04: 6 seconds, timed
Load Firefox: 2 seconds
Load Gimp: 2 seconds
Load Libreoffice essentially instantaneously...less than a second
Extract a 640MB tar/gzip archive: <2 seconds
Some things it doesn't do so well:
Encode a 4GB mp4 to 1080p 60fps (same as the recording) using OpenShot Video Editor: 23 minutes
(I have no idea whether this software uses the GPU. It uses ffmpeg for encoding.)
Temperature data
Ambient temp. 20 deg. C
Stress test the CPU at 100% - max CPU core temp 56 deg. C
Flightgear for 1 hour - max GPU temp 68 deg. C, max CPU temp 57 deg. C
(Note: The CPU is above the graphics card so it will get hotter when the GPU gets hotter)
These temperatures were much higher with two different passive CPU coolers. The case is narrow so only short coolers will fit. Running a CPU stress test, the CPU cores were over 80 and still climbing. Under normal use, they were in the 60s, but running a flight simulator pushed them, again, to a level I wasn't comfortable with. So I gave up on totally fanless and installed the Scythe 120. The results speak for themselves.
Issues
1) The first OCZ SSD died within the 2-year warranty window and was replaced.
2) The firewire card has never worked...appears to be a hardware problem. I didn't care until recently and have ordered a new card.
3) When a USB2 device is plugged into the USB3 port in the back, it often locks up the USB bus. You have to power the machine down by holding the start button for 5 seconds, then start it up again. Very annoying so I don't use the port.
4) I started out with 4GB of RAM. At times it wasn't enough, especially when running VMs. Adding another 4GB eliminated the problem. As noted above, I can't run and keep track of enough tasks to overload the machine.
Summary
Many people have used the G2120 in their builds because the combination of performance, price and low power is hard to beat. SPCR has reviewed an actively cooled card with the 6670 GPU, but this particular card is passively cooled. That has proved to be sufficient in the Nofan case with no high-temp cards below it. Combining these two processing units with SATA III and an SSD yields a fast, responsive system for day-to-day tasks. To my ears it's totally silent, but I'm 65 years old and my hearing isn't what it used to be. For those who want hard numbers, SPCR has tested the version of this fan without PWM: http://www.silentpcreview.com/article83 ... .html#SS-M