The hardware chosen was picked to reflect that of a relatively modern computer system that an enthusiast may own. The configuration of the system is as follows:
In the installation of our test hardware, no major issues were encountered. There were really only two major pieces of hardware we were concerned about, CPU coolers and video cards. With CPU coolers, we installed the largest one we have on hand, Noctua's NH-D14, and there were no clearance issues. With some other cases we reviewed, we encountered issues where the cooler is too tall, and as a result the side panel wasn't able to be closed. But not with the Define R3. If you have a large heatsink, you won't however be able to install a fan on the side panel.
With video cards, we installed a Radeon 4870 which is 9.5 inches long. There were no problems with fit. You should also be able to install any other video card up to 11 inches. If your card is exactly 11 inches like a lot of the new high end Radeon 6970/7970 cards, it should fit, but it will be a tight fit (the PCIe power connectors). Longer video cards, like those with dual GPUs will probably not fit.
Our power supply, an Antec Signature, is a bit longer than the average power supply, but it fit fine. With longer power supplies, you should have no problems with the fit, but you will have to remove the bracket for the fan mounting bracket at the bottom of the case.
We were able to route cables and wires relativevly neatly around and behind the motherboard tray, but the fit between the motherboard tray and the side panel were tight. The hole on motherboard tray easily provided enough clearance to install the Noctua CPU cooler.
As we don't have a standardized test system in place for cooling performance testing of cases, no charts or numbers are included in the review. To ensure the case was able to adequately handle a high heat load, a 24 hour stress test was run on the installed test hardware. The Core i7-2700k processor was overclocked to 4Ghz. While the Radeon 4870 in the system isn't exactly a modern GPU by any standards, it's known to run as a very hot GPU when under heavy load. The CPU was loaded up on all cores with OCCT, and the GPU was stressed using Furmark. The system successfully ran through 24 hours on stress test mode while installed in the Define R3.
Considering the stress test successfully ran with only two of the fan slots populated (with the included Fractal Design fans), it would be no surprise if the Define R3 was able to provide leading cooling performance with the five other fan slots populated.