678 PC Case Airflow Mods

[Mark13]

I finally found someone local with a water-jet who could cut the front & rear panels of my 678 PC case.

Earlier testing had shown that with no air flow through the front or rear panels, the case would gradually fill up with heated air and temperatures would continue to rise even when a larger air cooler such as the Alpenfoehn Blackridge was installed. I would have preferred to have the front panel in the same large hexagon pattern as the side panels, but unfortunately the case has ceased production. The large hexagons also fit the included power switch that extend too deeply into the case to clear the Blackridge cooler in its original center of the front panel position. I am particularly pleased with the large rear panel slots allowing the CPU cooler to draw fresh air from underneath the PSU that was previously completely blocked off.

I find the 678 case very clever in design using a bare minimum of individual parts such as including incorporating the case feet into the side panels and the PSU air vent on the top case panel. The build is quite tight, and even the A9x14 fan when installed internally is being pressed against by the motherboard 24 pin connector.

For this build I upgraded the CPU from my earlier 8 core 4750G Pro to the 8 core 5700G. The 5700G is approximately 10% faster in tasks than the 4750G, but does run noticeably hotter than the 4750G despite not drawing more wattage.

I found in earlier case testing that an exhaust case fan configuration is preferred when using a down draft CPU cooler. For normal day to day activities such as watching YouTube videos, no case fan is required as the CPU temperatures remained under 50C and the A9x25 fan is extremely quiet spinning at about 1370 RPM.

Below are the test results using the Noctua L9A cooler with the A9x25 Cromax black fan. Test results show that when stress testing the build a case fan is needed. Stress testing without a case fan was stopped after 5 minutes as the CPU temperature reached 95C. The test demonstrates how even a small case fan in an enclosure with adequate airflow can be substantially improved. Blackridge CPU cooler with A12x15 fan installed in last column. The Blackridge cooler is ideal in this case as the fins run from front to back through the case allowing air to be pushed out both the front & back of the case.

Ryzen 7 5700G Aorus B550 ITX MB
Noctua L9A CPU Cooler with A9x25 Fan
RAM 32 GB Corsair LPX @3200
PNY 3060 GPU
678 Case with modded front & rear panels
Case Fan – None / A9x14 / A9x15
10 min CPU Z Stress Test & Unigine Valley @1080P Ultra
@24C:

Case Fan Front Exhaust​	​	None​	A9x14 internal​	A12x15 external​
Temp​	Temp TZ10​	16.8​	16.8​	16.8​
​	TMPIN0​	54​	52​	52​
​	TMPIN1​	53​	51​	49​
​	TMPIN2​	95*​	90​	89​
​	TMPIN3​	22​	22​	21​
​	TMPIN4​	53​	51​	50​
​	TMPIN5​	55​	52​	51​
Fans​	CPU Fan RPM​	1928​	1950​	1864​
​	Case Fan RPM​	N/A​	2636​	1795​
Temp​	PKG Temp​	95.4*​	90.4​	89​
Power​	Cores Max Watt​	58.83​	60.4​	59.55​
SSD​	Top​	52​	50​	49​
​	Bottom​	45​	45​	44​
Temp​	GPU​	72​	71​	71​
​	Hotspot​	83.3​	83​	82.9​
GPU Fan​	Fan RPM​	1704​	1620​	1610​
GPU Watt​	GPU Watt​	164.4​	166.95​	166.56​
​	30 CM dba​	42​	46.7​	45.7​
​	​	​	​	​
* test ended after 5 minutes due to continually rising temperatures​	​	​	​	​

Updated testing results adding Noctua A9x25 front exhaust fan placed as low as possible on the front panel opening.

Case Fan Front Exhaust​	​	None​	A9x14 internal​	A12x15 external​	A9x25 external​
Temp​	Temp TZ10​	16.8​	16.8​	16.8​	16.8​
​	TMPIN0​	54​	52​	52​	51​
​	TMPIN1​	53​	51​	49​	48​
​	TMPIN2​	95*​	90​	89​	86-84​
​	TMPIN3​	22​	22​	21​	21​
​	TMPIN4​	53​	51​	50​	49​
​	TMPIN5​	55​	52​	51​	50​
Fans​	CPU Fan RPM​	1928​	1950​	1864​	1945​
​	Case Fan RPM​	N/A​	2636​	1795​	2033​
Temp​	PKG Temp​	95.4*​	90.4​	89​	86.5​
Power​	Cores Max Watt​	58.83​	60.4​	59.55​	59.73​
SSD​	Top​	52​	50​	49​	48​
​	Bottom​	45​	45​	44​	43​
Temp​	GPU​	72​	71​	71​	71​
​	Hotspot​	83.3​	83​	82.9​	82.7​
GPU Fan​	Fan RPM​	1704​	1620​	1610​	1606​
GPU Watt​	GPU Watt​	164.4​	166.95​	166.56​	166.87​
​	30 CM dba​	42​	46.7​	45.7​	46.1​
​	​	​	​	​	​
* test ended after 5 minutes due to continually rising temperatures​	​	​	​	​	YouTube @39C​
​	​	​	​	​	​
​	​	​	​	​	​

​	​	​	​	​	​	Alpenfoehn​
​	​	​	​	​	​	Blackridge​
​	​	​	​	​	​	A12x15 Fan​
Case Fan Front Exhaust​	​	None​	A9x14 internal​	A12x15 external​	A9x25 external​	None​
Temp​	Temp TZ10​	16.8​	16.8​	16.8​	16.8​	16.8​
​	TMPIN0​	54​	52​	52​	51​	52​
​	TMPIN1​	53​	51​	49​	48​	52​
​	TMPIN2​	95*​	90​	89​	86-84​	85-83​
​	TMPIN3​	22​	22​	21​	21​	22​
​	TMPIN4​	53​	51​	50​	49​	53​
​	TMPIN5​	55​	52​	51​	50​	53​
Fans​	CPU Fan RPM​	1928​	1950​	1864​	1945​	1790​
​	Case Fan RPM​	N/A​	2636​	1795​	2033​	N/A​
Temp​	PKG Temp​	95.4*​	90.4​	89​	86.5​	85.8​
Power​	Cores Max Watt​	58.83​	60.4​	59.55​	59.73​	59.44​
SSD​	Top​	52​	50​	49​	48​	49​
​	Bottom​	45​	45​	44​	43​	46​
Temp​	GPU​	72​	71​	71​	71​	72​
​	Hotspot​	83.3​	83​	82.9​	82.7​	83.4​
GPU Fan​	Fan RPM​	1704​	1620​	1610​	1606​	1696​
GPU Watt​	GPU Watt​	164.4​	166.95​	166.56​	166.87​	169​
​	30 CM dba​	42​	46.7​	45.7​	46.1​	42.4​
​	​	​	​	​	​	​
* test ended after 5 minutes due to continually rising temperatures​	​	​	​	​	Fan offset to​	​
​	​	​	​	​	bottom front​	​
​	​	​	​	​	panel opening​	​

I did some additional testing with the 678 case swapping out the RTX 3060 for a half height / motherboard-power-only RTX A2000 blower style GPU to see how large a reduction there would be in internal component temperatures with this GPU. As I have another project in the works,subsequently I removed the entire internal components of this PC and tested again using the A2000 on an open test bench to determine just how much heat was being retained in a case under 7 liters in volume. One interesting item – the bottom NVMe drive is hotter in the open test bench than when installed in the case as the thick thermal pad installed on the bottom drive presses firmly against the thick steel bottom case panel that acts as a very large heat sink. The Blackridge cooler with the Noctua A12x15 fan keeps all components reasonably cool, but the open test bench shows just how much heat is being retained in a case with the PSU directly above the CPU/motherboard: +6C on the CPU.

Ryzen 7 5700G Aorus B550 ITX MB​	​	​	​	​	​	​	​	​	​
RAM 32 GB Corsair LPX @3200​	​	​	​	​	​	​	​	​	​
678 Case with modded front & rear panels except last column – open test bench​	​	​	​	​	​	​	​	​	​
Case Fan – None / A9x14 / A9x25​	​	​	​	​	​	​	​	​	​
10 min CPU Z Stress Test & Unigine Valley @1080P Ultra​	​	​	​	​	​	​	​	​	​
@24C​	​	​	​	​	​	​	​	​	​
Case​	​	678 Case​	678 Case​	678 Case​	678 Case​	678 Case​	678 Case​	678 Case​	Open Test Bench​
GPU​	​	PNY 3060​	PNY 3060​	PNY 3060​	PNY 3060​	PNY 3060​	PNY 3060​	A2000​	A2000​
​	​	Noc L9A​	Noc L9A​	Noc L9A​	Noc L9A​	Alpenfoehn​	Alpenfoehn​	Alpenfoehn​	Alpenfoehn​
​	​	A9x25​	A9x25​	A9x25​	A9x25​	Blackridge​	Blackridge​	Blackridge​	Blackridge​
​	​	​	​	​	​	A12x15 Fan​	A12x15 Fan​	A12x15 Fan​	A12x15 Fan​
Case Fan Front Exhaust​	​	None​	A9x14 internal​	A12x15 external​	A9x25 external​	None​	A9x14 external​	None​	None​
Temp​	Temp TZ10​	16.8​	16.8​	16.8​	16.8​	16.8​	16.8​	16.8​	16.8​
​	TMPIN0​	54​	52​	52​	51​	52​	52​	52​	49​
​	TMPIN1​	53​	51​	49​	48​	52​	52​	49​	44​
​	TMPIN2​	95*​	90​	89​	86-84​	85-83​	84​	78​	72​
​	TMPIN3​	22​	22​	21​	21​	22​	22​	21​	21​
​	TMPIN4​	53​	51​	50​	49​	53​	53​	51​	46​
​	TMPIN5​	55​	52​	51​	50​	53​	52​	53​	50​
Fans​	CPU Fan RPM​	1928​	1950​	1864​	1945​	1790​	1767​	1748​	1721​
​	Case Fan RPM​	N/A​	2636​	1795​	2033​	N/A​	2220​	N/A​	N/A​
Temp​	PKG Temp​	95.4*​	90.4​	89​	86.5​	85.8​	84.6​	78.1​	72.6​
Power​	Cores Max Watt​	58.83​	60.4​	59.55​	59.73​	59.44​	59.04​	60.01​	60.5​
SSD​	Top​	52​	50​	49​	48​	49​	48​	45​	40​
​	Bottom​	45​	45​	44​	43​	46​	Not noted​	45​	52​
Temp​	GPU​	72​	71​	71​	71​	72​	72​	77​	73​
​	Hotspot​	83.3​	83​	82.9​	82.7​	83.4​	83.6​	83.1​	80​
GPU Fan​	Fan RPM​	1704​	1620​	1610​	1606​	1696​	1714​	40% 3548​	45% 3770​
GPU Watt​	GPU Watt​	164.4​	166.95​	166.56​	166.87​	169​	73.1​	73.3​	72​
​	30 CM dba​	42​	46.7​	45.7​	46.1​	42.4​	45.9​	43.7​	43.7​
​	​	​	​	​	​	​	​	​	​
* test ended after 5 minutes due to continually rising temperatures​	​	​	​	​	​	​	​	​	​

 

[BaK]

I find the 678 case very clever in design using a bare minimum of individual parts such as including incorporating the case feet into the side panels and the PSU air vent on the top case panel.

Nice case, à la Silvertsone SG05 somehow but with a look of its own.
Good job on the added air vents!