| Forum Home | ||||
| Press F1 | ||||
| Thread ID: 66196 | 2006-02-14 20:40:00 | Adding cooling | The_End_Of_Reality (334) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 430323 | 2006-02-15 03:41:00 | fistly what sort of case cooling have you got already? 1 fan on the side window, 4 fans blowing in from the front, 2 extracting from the back, plus the PSU 2,(all previous are 80mm), stock CPU (92mm I THINK) and GFX (not sure about). I was thinking of adding an extra 120mm fan in the top as said in my first post to extract the hot air out |
The_End_Of_Reality (334) | ||
| 430324 | 2006-02-15 03:56:00 | Why have another extractor fan? You should have fans: drawing in "cool" air and pressurising the case, so the hot air has to escape through vents, or extracting hot air, so it will be replaced by cool air entering through vents . A combination means that, unless you have the suckers and the blowers exactly matched, some of the fans are obstructing the air flow . That is not helpful . What is needed is proper flow of air . If I ever get CPUs and video units which are so hot, I would spend some time making proper ducting to direct air flow where it's needed . Isn't the new motherboard design supposed to do this (for the CPU, anyway)? |
Graham L (2) | ||
| 430325 | 2006-02-15 03:58:00 | 1 fan on the side window, 4 fans blowing in from the front, 2 extracting from the back, plus the PSU 2,(all previous are 80mm), stock CPU (92mm I THINK) and GFX (not sure about) . I was thinking of adding an extra 120mm fan in the top as said in my first post to extract the hot air out sounds like either somethings not setup correctly or the temp sensors reading high . check room temp, then put that thermometer in the case and see what it reads . if anything fine tune the existing cooling before adding more fans |
tweak'e (69) | ||
| 430326 | 2006-02-15 04:48:00 | tweak'e, I have a clock that is also thermometer, it was reading 23 in the room, Put it into the bottom of the case (only place there is room atm) and started video encoding, 30 min after starting it is now reading 35 inside, and hot air rises so it is bound to be hotter up top. I will post when the encoding is nearly finished with the temperature. Graham L, I have many fans blowing in and they don't appear to be forcing out the hot. If I do put in a 120mm fan it will be able to draw in extra air from the 3.5' and 5.25' drive bays that I have left the covers off to increase air flow. They say it is, but I don't see how it can change it much, the only real diff on my mobo is the position of the RAM, which is above the CPU |
The_End_Of_Reality (334) | ||
| 430327 | 2006-02-15 04:56:00 | The amount of air moving is not all that important . Where it moves is important . If you suck air in through drive bays (near the top?) and out through a fan on the "roof" you are doing nothing to cool the CPU and GPU . The ideal would be cool external air going straight to the heat exchangers on those hot components, then straight out . The PSU's fan would look after it, and probably the rest of the components (except perhaps some disks which might run hot) . Your two "extractor" fans might be reducing the amount of air leaving . Try removing them . :D |
Graham L (2) | ||
| 430328 | 2006-02-15 04:56:00 | . . . . I am wanting something that is relatively quiet, 120mm but with a fair CFM, at least over 150CFM . Sounds like the end of reality all right :p You wont get a fan to do that, not at that size anyway . 65dbA is just ridiculous by any standards . Anything over around 35dbA is going to sound irritating especially to young keen sharp ears . So you want a fan (120mm) at around 2200rpm, but that will only give about 85cfm under ideal conditions, so you would need to go up in size and bring the speed down further so that the blade tip speed is not too high . If you look at the Delta curves, 150cfm is for very small pressure rise, ie no outlet restriction . Something like a 300mm fan at 1000rpm (at a guess) would give the flow you ask for in free air conditions . But you are not in free air conditions, there is a basic inviolate law that says (mass)flow in =(mass)flow out . But air is compressible, so pressure will either rise in the case if you try to pump in more volume flow than can get out (in terms of volume flow), or it will drop if you try to extract more volume flow than can get in (in terms of volume flow) Roughly the total inlet area into a case should be equal to the outlet area, or preferably and better still, the outlet area should be greater . What I'm getting around to saying is that if you add a 120mm extractor fan, then you need to add a 120mm inlet hole for the air to get in . In the ridiculous extreme, you could add such a powerful extractor that air would be sucked back in through the PSU, or worse, make the air in the PSU stagnant :stare: It all comes around to careful balance and appreciation of what is happening, together maybe with some "simple" measurements of flows say with a pitot or wind speed meter, pressures using a water manometer, and temperatures using thermocouple . But without some equipment that is not so easy to do . |
Terry Porritt (14) | ||
| 430329 | 2006-02-15 05:30:00 | Graham L, there are 4 80mm fans blowing in from infront of the 3.5' drive bays at the bottom, with the extractor fan where I plan to put it if I do put one in, the front will blow over the HDDs onto the GFX and the extractor will suck that over the CPU and out the top. Terry Porritt, you know me too well :D :p, though I was talking to a friend and he said that having 100CFM would be pleanty if not a tad too much, this would be about the same as the fans blowing in, which is what you are talking about with the total inlet and total outlet. BTW I have selective hearing :p, I can block out noises, LOL I don't even notice my PC as it is :p An update on the temp, after 1 hour 15 mins the temp is at 37 in the bottom |
The_End_Of_Reality (334) | ||
| 430330 | 2006-02-15 05:51:00 | I wonder if you could beg borrow or steal a digital multimeter with thermocouple probe from someone. Then you could check temperatures all around the case. It bothered me a bit that you reported a 'system' temperature of 50C and a CPU temperature of around 47C, it would be interesting to see what the temperature is of the air being drawn into the CPU fan. A thing to remember when cpu temperatures are being bandied around is that a typical stock heatsink and fan has a heat transfer factor of around 0.5 C/W, give or take. If the cpu is running at 40 watts (and it could be 60 or more say), then the temperature rise is around a minimum of 20C. There's not much getting away from this without going to exotic cooling equipment. So if air temperature going into the cpu fan is around 25C, and it is not going to be much less than this, unless it is a winters day, then cpu temperature will be around 45C (or more). That is why temperature talk of 35C etc has to be taken with a pinch of salt :) |
Terry Porritt (14) | ||
| 430331 | 2006-02-15 06:02:00 | Terry, haven't you heard? The laws of thermodynamics have been repealed. They don't comply with the Treaty of Waitangi, and certainly don't fit with the Knowledge economy and market ideology. | Graham L (2) | ||
| 430332 | 2006-02-15 06:03:00 | I will see if the electronics department at my school has one I could borrow :) Yes, I read somewhere that the sensor for this is somewhere around the chipset, and that is right below my GFX card, so that might have something to do with it being so high :confused: |
The_End_Of_Reality (334) | ||
| 1 2 3 4 5 6 7 8 9 | |||||