vacuum in case?

**magnethead** · 06-04-2007, 02:22 AM

ok, just since i've noticed before, i popped the side of my case off. Instantly the fans audibly quieted. And more air came out of the fans with the side off than side on (expected).

Being as i have roughly 4 times the CFM exhausting than i do intake CFM, with all other openings in the case sealed, am I maybe creating too much of a vacuum in my computer case and overworking the fans?

Edit: I just unhooked my side fan power and blocked it's grille, now the sound difference isn't anything near what it was, and is bout equal with slot fan on medium (rated24.5 CFM@2000 RPM, upposed to 37.5 CFM @ 2600 high speed).

**MunkyPhil** · 06-04-2007, 03:00 AM

If you have significantly more CFM going out than in and your case is as good as sealed more air is going to force its way in through the intake fan and the fan wont operate properly, having abnormal forces on it. This will reduce the life of the fan. I'd try to even the CFM out (intake = output) or create a 'hole' somewhere so that the pressure can even itself out, I've removed the metal expansion slot thingies from my case.

Don't hesitate to post back with further questions.

**magnethead** · 06-04-2007, 01:58 PM

well as i said my my initial edit, i took the side fan out, and i just swapped case sides back with my dad's computer so i don't have the side vent. I covered the rear holes next to the PCI slots, and right now am at 97 degrees with the CPU fan screaming.

**MunkyPhil** · 06-05-2007, 02:34 AM

You need vents magnethead, you need a way for the pressure to even itself out or your fan will break sooner rather than later. Your fan is screaming because air is forcing its way through the fan at a greater rate than the fan is made for and an excess force in the direction of the airflow is being put on the fan. This excess air should be brought in through vents so make some holes and change the fans around to even out the CFM. Is that 97ºF or 97ºC? I hope it's not the latter, 97ºF is OK for a CPU temp (case temp a little high for idling) but can be improved with better airflow.

**magnethead** · 06-05-2007, 02:04 PM

well the only reason i have them block is because they would create an air-short between my slot fan and the vents (being as they are right next to eachother). And it's not the front fan that's scremaing, it's dead quiet (but on). The CPU exhaust fan is the one screaming until i remove the case side. I'd like to have more front vents but between the dell chassis and dell faceplate, not exactly easy.

the side vents on my dad's case are also at the PCI slots, so that would also be an air-short.

right now i'm at 95/82 farenheit for my hard drives (SATA/IDE respectively). As soon as i locate my ambient thermometer i'll have a case reading.

**magnethead** · 06-05-2007, 03:18 PM

ok, case temp is 85 degrees F.

the PSU calculator says i need 400 watts optimal for my system, my dell PSU is 250 watts, if maybe over-draw of the PSU is not helping in the heat deptartment?

PSU side panel: "250 w max: +12: 16A; +3.3: 18A; +5VSB: 2A"

**1 g0t 0wn3d** · 06-05-2007, 03:21 PM

Well then you need a new psu around 500 watts good brand for upgrades later.

**magnethead** · 06-05-2007, 03:33 PM

I just edited that post for what i was able to read off the PSU. Is that case temp in check for basically being idle?

I just ran the calculator for when my computer was bone stock, it says even then it needed a 280 watt unit. Something is not right, granted i'm sure the calculator isn't always close.

06-04-2007, 02:22 AM	#1 (permalink)
magnethead Registered User Join Date: Mar 2006 Location: Texas, USA Posts: 3,570 OS: Vista ultimate 32bit My System Blog Entries: 3	vacuum in case? ok, just since i've noticed before, i popped the side of my case off. Instantly the fans audibly quieted. And more air came out of the fans with the side off than side on (expected). Being as i have roughly 4 times the CFM exhausting than i do intake CFM, with all other openings in the case sealed, am I maybe creating too much of a vacuum in my computer case and overworking the fans? Edit: I just unhooked my side fan power and blocked it's grille, now the sound difference isn't anything near what it was, and is bout equal with slot fan on medium (rated24.5 CFM@2000 RPM, upposed to 37.5 CFM @ 2600 high speed). __________________ For proper support: what are you running? graphics, cpu, m/board, ram, PSU brand wattage PCI-E requires 26 amps at 12 volts. That's a 650W PSU. Power Supply Info and Selection . Info on thermal compounds & application . TEST PSU USING MULTI-METER . Bench Testing Your System Last edited by magnethead; 06-04-2007 at 02:31 AM.

06-04-2007, 03:00 AM	#2 (permalink)
MunkyPhil TSF Enthusiast Join Date: Apr 2006 Location: Liverpool, England Posts: 1,140 OS: Win XP Pro SP2 My System	Re: vacuum in case? If you have significantly more CFM going out than in and your case is as good as sealed more air is going to force its way in through the intake fan and the fan wont operate properly, having abnormal forces on it. This will reduce the life of the fan. I'd try to even the CFM out (intake = output) or create a 'hole' somewhere so that the pressure can even itself out, I've removed the metal expansion slot thingies from my case. Don't hesitate to post back with further questions. __________________ "Now I am become death, the destroyer of worlds." - J. Robert Oppenheimer, July 16th 1945. CPU-z -- Memtest -- Speedfan -- Prime95 -- SandraLite Important Power Supply Info -- Applying Thermal Paste -- Posting System Specs

06-04-2007, 01:58 PM	#3 (permalink)
magnethead Registered User Join Date: Mar 2006 Location: Texas, USA Posts: 3,570 OS: Vista ultimate 32bit My System Blog Entries: 3	Re: vacuum in case? well as i said my my initial edit, i took the side fan out, and i just swapped case sides back with my dad's computer so i don't have the side vent. I covered the rear holes next to the PCI slots, and right now am at 97 degrees with the CPU fan screaming. __________________ For proper support: what are you running? graphics, cpu, m/board, ram, PSU brand wattage PCI-E requires 26 amps at 12 volts. That's a 650W PSU. Power Supply Info and Selection . Info on thermal compounds & application . TEST PSU USING MULTI-METER . Bench Testing Your System

06-05-2007, 02:34 AM	#4 (permalink)
MunkyPhil TSF Enthusiast Join Date: Apr 2006 Location: Liverpool, England Posts: 1,140 OS: Win XP Pro SP2 My System	Re: vacuum in case? You need vents magnethead, you need a way for the pressure to even itself out or your fan will break sooner rather than later. Your fan is screaming because air is forcing its way through the fan at a greater rate than the fan is made for and an excess force in the direction of the airflow is being put on the fan. This excess air should be brought in through vents so make some holes and change the fans around to even out the CFM. Is that 97ºF or 97ºC? I hope it's not the latter, 97ºF is OK for a CPU temp (case temp a little high for idling) but can be improved with better airflow. __________________ "Now I am become death, the destroyer of worlds." - J. Robert Oppenheimer, July 16th 1945. CPU-z -- Memtest -- Speedfan -- Prime95 -- SandraLite Important Power Supply Info -- Applying Thermal Paste -- Posting System Specs

06-05-2007, 02:04 PM	#5 (permalink)
magnethead Registered User Join Date: Mar 2006 Location: Texas, USA Posts: 3,570 OS: Vista ultimate 32bit My System Blog Entries: 3	Re: vacuum in case? well the only reason i have them block is because they would create an air-short between my slot fan and the vents (being as they are right next to eachother). And it's not the front fan that's scremaing, it's dead quiet (but on). The CPU exhaust fan is the one screaming until i remove the case side. I'd like to have more front vents but between the dell chassis and dell faceplate, not exactly easy. the side vents on my dad's case are also at the PCI slots, so that would also be an air-short. right now i'm at 95/82 farenheit for my hard drives (SATA/IDE respectively). As soon as i locate my ambient thermometer i'll have a case reading. __________________ For proper support: what are you running? graphics, cpu, m/board, ram, PSU brand wattage PCI-E requires 26 amps at 12 volts. That's a 650W PSU. Power Supply Info and Selection . Info on thermal compounds & application . TEST PSU USING MULTI-METER . Bench Testing Your System Last edited by magnethead; 06-05-2007 at 02:22 PM.

06-05-2007, 03:18 PM	#6 (permalink)
magnethead Registered User Join Date: Mar 2006 Location: Texas, USA Posts: 3,570 OS: Vista ultimate 32bit My System Blog Entries: 3	Re: vacuum in case? ok, case temp is 85 degrees F. the PSU calculator says i need 400 watts optimal for my system, my dell PSU is 250 watts, if maybe over-draw of the PSU is not helping in the heat deptartment? PSU side panel: "250 w max: +12: 16A; +3.3: 18A; +5VSB: 2A" __________________ For proper support: what are you running? graphics, cpu, m/board, ram, PSU brand wattage PCI-E requires 26 amps at 12 volts. That's a 650W PSU. Power Supply Info and Selection . Info on thermal compounds & application . TEST PSU USING MULTI-METER . Bench Testing Your System Last edited by magnethead; 06-05-2007 at 03:32 PM.

06-05-2007, 03:21 PM	#7 (permalink)
1 g0t 0wn3d TSF Enthusiast Join Date: Jan 2007 Location: Sedona, az Posts: 6,528 OS: Vista basic 32bit My System	Re: vacuum in case? Well then you need a new psu around 500 watts good brand for upgrades later. __________________ Bench Test \| PC Wizard \| System specs \| PSU info \| PSU calculator \| Memtest86+ \| Speedfan

06-05-2007, 03:33 PM	#8 (permalink)
magnethead Registered User Join Date: Mar 2006 Location: Texas, USA Posts: 3,570 OS: Vista ultimate 32bit My System Blog Entries: 3	Re: vacuum in case? I just edited that post for what i was able to read off the PSU. Is that case temp in check for basically being idle? I just ran the calculator for when my computer was bone stock, it says even then it needed a 280 watt unit. Something is not right, granted i'm sure the calculator isn't always close. __________________ For proper support: what are you running? graphics, cpu, m/board, ram, PSU brand wattage PCI-E requires 26 amps at 12 volts. That's a 650W PSU. Power Supply Info and Selection . Info on thermal compounds & application . TEST PSU USING MULTI-METER . Bench Testing Your System Last edited by magnethead; 06-05-2007 at 03:44 PM.