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#1
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CPU Cooler designs?
Hi,
As I understand it, most ATX style PC setups have a fan above the CPU that blows air down onto the CPU to keep it cool, and the hot air bounces around inside the PC case until it can find an exit (if it's lucky). As I see it, there are two problems with this, a) unless you have a vent in the side of the PC case, the air being taken in by the CPU cooler will not be cool, because it's air from inside the PC case? b) the hot air from the bottom of the heat sink ends up warming up the Motherboard? I was looking at the Dell CPU coolers of the GX280, GX620 workstaions (Intel P4 / Pentium D) and the PE2400, PE 2600, PE2800 servers (Intel Xeon). The design is completely different. The air is sucked in from the front of the case, straight over the CPU and out of the back - how cool is that? Pretty cool, and there's hardly any noise either. -- Gerry_uk |
#2
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CPU Cooler designs?
Gerry_uk wrote
As I understand it, most ATX style PC setups have a fan above the CPU that blows air down onto the CPU to keep it cool, and the hot air bounces around inside the PC case until it can find an exit (if it's lucky). No luck involved, there is normally at least the power supply fan than moves the air inside the case to outside the case. As I see it, there are two problems with this, a) unless you have a vent in the side of the PC case, the air being taken in by the CPU cooler will not be cool, because it's air from inside the PC case? Quite a few of the later cases have a duct that supplys outside air to the cpu and fan. b) the hot air from the bottom of the heat sink ends up warming up the Motherboard? In practice that really doesnt produce much of a problem. I was looking at the Dell CPU coolers of the GX280, GX620 workstaions (Intel P4 / Pentium D) and the PE2400, PE 2600, PE2800 servers (Intel Xeon). The design is completely different. The air is sucked in from the front of the case, straight over the CPU and out of the back - how cool is that? Pretty cool, and there's hardly any noise either. Its just one way of doing things. |
#3
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CPU Cooler designs?
the dell solution is the BX rather than the ATX cooling
-john "Rod Speed" wrote in message ... Gerry_uk wrote As I understand it, most ATX style PC setups have a fan above the CPU that blows air down onto the CPU to keep it cool, and the hot air bounces around inside the PC case until it can find an exit (if it's lucky). No luck involved, there is normally at least the power supply fan than moves the air inside the case to outside the case. As I see it, there are two problems with this, a) unless you have a vent in the side of the PC case, the air being taken in by the CPU cooler will not be cool, because it's air from inside the PC case? Quite a few of the later cases have a duct that supplys outside air to the cpu and fan. b) the hot air from the bottom of the heat sink ends up warming up the Motherboard? In practice that really doesnt produce much of a problem. I was looking at the Dell CPU coolers of the GX280, GX620 workstaions (Intel P4 / Pentium D) and the PE2400, PE 2600, PE2800 servers (Intel Xeon). The design is completely different. The air is sucked in from the front of the case, straight over the CPU and out of the back - how cool is that? Pretty cool, and there's hardly any noise either. Its just one way of doing things. |
#4
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CPU Cooler designs?
"Gerry_uk" wrote in message ... Hi, As I understand it, most ATX style PC setups have a fan above the CPU that blows air down onto the CPU to keep it cool, and the hot air bounces around inside the PC case until it can find an exit (if it's lucky). As I see it, there are two problems with this, a) unless you have a vent in the side of the PC case, the air being taken in by the CPU cooler will not be cool, because it's air from inside the PC case? b) the hot air from the bottom of the heat sink ends up warming up the Motherboard? I was looking at the Dell CPU coolers of the GX280, GX620 workstaions (Intel P4 / Pentium D) and the PE2400, PE 2600, PE2800 servers (Intel Xeon). The design is completely different. The air is sucked in from the front of the case, straight over the CPU and out of the back - how cool is that? Pretty cool, and there's hardly any noise either. -- Gerry_uk My Gigabyte Aurora pulls air in from front bottom via 120mm fan and then expels it from the back via two 120mm fans at middle and top of chassis. Now, if I position the Zalman 9500 so that its fan intake side is parallel to the front of the case(facing it), then the CPU cooler should actually help facilitate the cooling air flow as the external air is pulled in from front bottom, passed through the CPU cooler fan/fins and proceeds out the back. No whirling flow patterns, just a nice line through the case and over the motherboard. Only problem: My OCZ PS has a fan underneath its case pointing downward at the mobo with another out the back. Hopefully, this downward fan actually sucks air up through the PS box and out the back. If so, it will probably add even more to the air evac. If not, then there's a flow conflict. We'll see when I get it all hooked up. But there is no other fan blowing air down from above and I've never seen any ATX case that deliberately does this either. Only from PSUs that have bottom fans. My old Supermicro full tower does the exact same thing. Cool air from front bottom to exhaust fans back top. This isn't new thermal management, they've been doing this for awhile. Even side air duct cases have been out for awhile. Ron |
#5
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CPU Cooler designs?
On Sat, 23 Sep 2006 23:06:52 +0100, Gerry_uk
wrote: Hi, As I understand it, most ATX style PC setups have a fan above the CPU that blows air down onto the CPU to keep it cool, and the hot air bounces around inside the PC case until it can find an exit (if it's lucky). No, a properly set up case has a bottom front intake and a center and top rear exhaust. Heated air exhausted out of the heatsink is moving towards the exhaust fans at all times. A small percentage of it will get recirculated back though the heatsink, BUT, attempts to change this will typically reduce overall airflow, so it can have a diminishing return (or even be worse) trying to minimize recirculation. As I see it, there are two problems with this, a) unless you have a vent in the side of the PC case, the air being taken in by the CPU cooler will not be cool, because it's air from inside the PC case? You do not want a vent in the side unless the entire system is set up to still maintain reasonable airflow considering the effect of that side vent. Remember one very important factor in proper system setup: Each part is supposed to have adequate heat removal method, including sufficient 'sink. The focus is never to try to get CPU the most air, nor most cool air. Incoming air does as described above, comes on the bottom front and travels towards the top rear. It is supposed to remove the heat from the HDDs, southbridge or single-chip on motherboard, flow by the video card, and anything else in this lower/mid region. If you try to change this flow by drawing in air near the CPU, you will necessarily reduce cooling of the other parts unless other addt'l accomdations are made to cool them. The CPU has a huge heatsink on it, these other parts do not (even video card, is not usually "huge" in comparison). The other parts depend on the passive airflow while the CPU has a fan. b) the hot air from the bottom of the heat sink ends up warming up the Motherboard? It doesn't matter because: 1) The air is not extremely hot, parts that don't produce much heat can stand to be a little warmer than they would have been had there been no CPU heat. 2) The few parts that are warmer than this heated air, will be cooled by it still. I was looking at the Dell CPU coolers of the GX280, GX620 workstaions (Intel P4 / Pentium D) and the PE2400, PE 2600, PE2800 servers (Intel Xeon). The design is completely different. No, the design is exactly the same, except they do without the CPU sink fan by putting a duct on the rear. It can be quieter, or it can be same noise level as a well-designed system. The reason for this is that the rear fan has to spin faster because of the snorkel, and because you wouldn't be comparing apples:apples if only considering systems that don't use RPM-reduced throttling of the fans as the Dell systems typically do. The reality is that Dell saves $1 or 2 by eliminating one fan, but if a system is not budget constrained (or profit maximized, however you want to look at it), the alternative system can run cooler than Dell's can, because the rear fan can more more air without the duct, and a heatsink with a fan on it can have that fan running at low enough RPM that it is not descriminable over the noise of the rear fan (what little there is). In the end, there is one simple truth: You have a case that has parts producing X amount of heat. The heat buildup of the parts inside depends on the total airflow rate in and out of the system. When Dell uses the snorkel on the rear fan, it has a lower airflow:noise ratio and thus, for the given level of noise the lower airflow does not get the heat out as fast, the chassis internal temp average is higher. In some systems, spot-measurements of a given component will be cooler in the Dell system. In others, warmer in the Dell. On average, the Dell will be warmer overall, so if you are concerned about CPU heat as it appeared when starting your post, the most significant factor may be whether the heatsink quality is better than Dell's or not. It is a large market with many different 'sinks, some are better, others are worse. The air is sucked in from the front of the case, straight over the CPU and out of the back - how cool is that? Pretty cool, and there's hardly any noise either. Cool? That's how many OEM systems have been set up for years. If you want you can build your own like this, all you need is to fabricate your own rear exhaust snorkel and a suitable heatsink designed for passive cooling (typically tall wider spaced tines instead of shorter, denser spaced fins). |
#6
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CPU Cooler designs?
On Sat, 23 Sep 2006 22:53:24 GMT, "Major Ninth"
wrote: the dell solution is the BX rather than the ATX cooling On today's new systems, yes, but we have no idea which the OP is looking at to make the observation... Dell has been doing similar to what was described for years, as have other OEMs. |
#7
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CPU Cooler designs?
"Gerry_uk" wrote in message
... Hi, As I understand it, most ATX style PC setups have a fan above the CPU that blows air down onto the CPU to keep it cool, and the hot air bounces around inside the PC case until it can find an exit (if it's lucky). As I see it, there are two problems with this, a) unless you have a vent in the side of the PC case, the air being taken in by the CPU cooler will not be cool, because it's air from inside the PC case? b) the hot air from the bottom of the heat sink ends up warming up the Motherboard? I was looking at the Dell CPU coolers of the GX280, GX620 workstaions (Intel P4 / Pentium D) and the PE2400, PE 2600, PE2800 servers (Intel Xeon). The design is completely different. The air is sucked in from the front of the case, straight over the CPU and out of the back - how cool is that? Pretty cool, and there's hardly any noise either. You could cut a hole in the side panel and put a shroud around the CPU fan so fresh cooler air gets sucked in and immediately used to cool the CPU rather than on relying on air that has entered a foot or more away and been pre-warmed by hard drives, memory sticks, Northbridge chip, or whatever is between the front case grill and the CPU. |
#8
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CPU Cooler designs?
"Vanguard" wrote in message ... "Gerry_uk" wrote in message ... Hi, As I understand it, most ATX style PC setups have a fan above the CPU that blows air down onto the CPU to keep it cool, and the hot air bounces around inside the PC case until it can find an exit (if it's lucky). As I see it, there are two problems with this, a) unless you have a vent in the side of the PC case, the air being taken in by the CPU cooler will not be cool, because it's air from inside the PC case? b) the hot air from the bottom of the heat sink ends up warming up the Motherboard? I was looking at the Dell CPU coolers of the GX280, GX620 workstaions (Intel P4 / Pentium D) and the PE2400, PE 2600, PE2800 servers (Intel Xeon). The design is completely different. The air is sucked in from the front of the case, straight over the CPU and out of the back - how cool is that? Pretty cool, and there's hardly any noise either. You could cut a hole in the side panel and put a shroud around the CPU fan so fresh cooler air gets sucked in and immediately used to cool the CPU rather than on relying on air that has entered a foot or more away and been pre-warmed by hard drives, memory sticks, Northbridge chip, or whatever is between the front case grill and the CPU. I was under the impression that you just want the hot air drawn off the components. I'm not so sure I'd want cool air pumped over my CPU. What happens when a cold front hits a warm front? I'm not suggesting it would rain inside my case, but wouldn't condensation come into play? My box will be in an AC environment and sometimes that cool air is actually cold. Now maybe the hot components stay hot enough to evaporate that, but just to make sure, I'll throw a couple of silicon packs in the bottom of my case. Think that'll help? : ) Ron |
#9
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CPU Cooler designs?
"Ron Krebs" wrote in
news:GglRg.1011$fl2.452@trnddc02: I was under the impression that you just want the hot air drawn off the components. I'm not so sure I'd want cool air pumped over my CPU. What happens when a cold front hits a warm front? I'm not suggesting it would rain inside my case, but wouldn't condensation come into play? My box will be in an AC environment and sometimes that cool air is actually cold. Now maybe the hot components stay hot enough to evaporate that, but just to make sure, I'll throw a couple of silicon packs in the bottom of my case. Think that'll help? : ) When the cool air hits the warm stuff inside the case it will get warmer and the relative humidity of that air will drop. If you had cold stuff in the case and you were pumping warm outside air onto it then you might have a condensation problem, as can occur with some extreme phase-change type coolers. -- ybbxvatyvxrnobeantnvayvivatyvxrnurergvpyvfgravatgb neguheyrrerpbeqfznxv atnyylbhesevraqfsrryfbthvyglnobhggurveplavpvfznaqg urerfgbsgurvetrareng vbaabgriragurtbireazragnertbaanfgbclbhabjohgnerlbh ernqlgborurnegoebxra |
#10
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CPU Cooler designs?
"Mitch Crane" -three wrote in message
.. . "Ron Krebs" wrote in news:GglRg.1011$fl2.452@trnddc02: I was under the impression that you just want the hot air drawn off the components. I'm not so sure I'd want cool air pumped over my CPU. What happens when a cold front hits a warm front? I'm not suggesting it would rain inside my case, but wouldn't condensation come into play? My box will be in an AC environment and sometimes that cool air is actually cold. Now maybe the hot components stay hot enough to evaporate that, but just to make sure, I'll throw a couple of silicon packs in the bottom of my case. Think that'll help? : ) When the cool air hits the warm stuff inside the case it will get warmer and the relative humidity of that air will drop. If you had cold stuff in the case and you were pumping warm outside air onto it then you might have a condensation problem, as can occur with some extreme phase-change type coolers. Guess Ron forgot that the air is *dryer* in winter when the air is colder hence the higher sales of humidifiers in winter. Silicon packs are useless when air is moving. They are used in sealed containers to remove what moisture is there and would be *trapped* there. |
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