Felger Carbon: "Definitely not better undervoltability. Reducing the cooling fin area is never a cooling win."
One should never say never. Whoopsie, I said it twice.
Consider a scenario when you have an unmodded Freezer 7 running at 7V (lower than can be recommended for most CPUs): airflow would probably be so low it's impossible to feel it due to airflow resistance of the heatsink. Also, with air moving slowly the exhaust air is pretty much the same temperature os the heatsink itself. This is because air can store very limited amount of heat per volume (because it's so thin).
If you use a heatsink that will have exhaust air at the same temperature as heatsink itself, the amount of transfered heat directly related to air passing through. I reality this is impossible as exhaust will be more or less cooler than fins. If we think of Freezer 7 at 7V we are relatively close to this assumption though because at 7V the airflow just drops too low to make the HSF useful.
If you were to increase surface area even further by creating a very big heatsink, say at least 10 to 20 cm long airflow path and keeping fin spacing the same as Freezer 7, the exhaust air will still be roughly the same (maybe increase just by few degrees), but the airflow resistance just got doubled, meaning airflow with same fan speed got lowered (=> reduced cooling) so more voltage is needed to be fed to the fan to compensate. After compensation (=> increased noise) you'd again have the same amount of airflow and roughly same exhaust temperature => same amount of total heat transfered... with the cost of extra noise.
Reducing cooling fin area is potential win when running HSF undervolted or passive. You can do this be increasing fin spacing or making fins shorter in dimension that's longitudal to airflow direction (reducing other dimensions would be bad).
I have strong belief based on SPCR's undervolting measurements that reducing cooling area would be beneficial for all but 12V operation (which is what this cooler most likely was optimized for). What I'm mostly worried about is whether cutting the fins using metal saw (since I don't own a dremel and it's bigger cousins are probably overkill) will damage the solder between heatpipes and fins. It may vibrate quite a bit when I do the cutting. I would cut the fins just a millimeter or two behind heatpipes and would sand the cut edge smooth so that there'd be no extra turbulence when air leaves the HSF.
Other mods I would consider for this HSF are
- blocking the sides of the heatsink so that centrifugal "force" doesn't blow air out the shortest route (this tendency is lowered by shortening the fins so it might not be necessary)
- creating a frame or even a duct for the fan to see if it increases turbulent noise and whether it increases useful airflow through the HSF. These frameless fans work OK when there's no backpressure, but considering how placing a Noctua fan (with frame) on floor with exhaust side blocked can create a noticeable amount of radial airflow from the intake side, it'll probably happen quite easily when adding backpressure to frameless fans.
Why did they make the fan push air into HS instead of sucking it? If it was sucking air out, even centrifugal airflow would contribute to airflow that passes through the HS. For sucking, frameless fans are no doubt better but for pushing air against backpressure... I don't get it.
Arctic Cooling Freezer 7 Pro - Socket 775 HSF
Different fan
I might have missed something, but can one use a different fan with this heatsink or does one have to use the one that comes with it? I was thinking of getting this and putting a Nexus 92mm on it (the unit only costs £11 from ebuyer, and I have some spare fans lying around). Or would the temperatures go bad?
Along similar lines, does anyone if there's a way of using a 120mm fan with this?
Oz
Along similar lines, does anyone if there's a way of using a 120mm fan with this?
Oz
Supplied fan not too bad
The heatsink has arrived, and like I suspected there doesn't seem to be an easy way of fitting one's own fan since, as the article says, the fan is rather oddly shaped. However, I can report that the supplied fan gets really rather quiet once you slow it down just a little bit. The default speed seems to be about 2250, but once you put it down to 1800 it gets really quite quiet.
In fact, I can run it at about 1000 RPM, still with good normal-usage/idle temperatures (36 C on the CPU, 30 C case, with two Nexus 80 mm case fans). This is on an Athlon 64 2800, so it is not exactly the same version as the one reviewed (I have the Freezer 64, not the Freezer 7). At full load, however, I need 1800-full speed, and so noise increases accordingly (this is to keep temperatures below about 50 C).
I'm controlling the fan speed through software (though my motherboard only has 3 pin plugs, not the 4 pin version that the supplied fan supports -- not sure what kind of functionality that 4th pin would offer). The 4 pin connector is backwards compatible with 3 pins by the way.
In fact, I can run it at about 1000 RPM, still with good normal-usage/idle temperatures (36 C on the CPU, 30 C case, with two Nexus 80 mm case fans). This is on an Athlon 64 2800, so it is not exactly the same version as the one reviewed (I have the Freezer 64, not the Freezer 7). At full load, however, I need 1800-full speed, and so noise increases accordingly (this is to keep temperatures below about 50 C).
I'm controlling the fan speed through software (though my motherboard only has 3 pin plugs, not the 4 pin version that the supplied fan supports -- not sure what kind of functionality that 4th pin would offer). The 4 pin connector is backwards compatible with 3 pins by the way.
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While I can't comment on what it would be like in an Intel system I can say that from my experience this makes for an excellent and inexpensive quiet replacement to the stock AMD duel core heatsink and fan. This is particularly so if you take advantage of using cool'n'quiet and any 'quiet fan' settings in your bios, which the fan been a PWM (Pulse-width modulation) model is able to be governed by.
I recently upgraded from a AMD64 3500+ (which I ran with the stock cooler since it was quiet enough) to a duel core AMD 5000+. Even with cool'n'quiet enabled and 'quiet fan' set as in my boards bios (Asus M2NPV-VM) the stock cooler on the duel core while quiet at idle became quickly noticeable under any sort of load.
I replaced it with the Freezer 64 Pro which was fairly easy to fit and I have been very happy with it. Since the fans speed is controlled by the bios (via PWM) at low usage it spins at about 1000rpm and keeps my CPU at around 22C. Even with both cores fully loaded video encoding temps don't rise above 48c (with the stock cooler it was around 60-62c) and RPM rises to around 1500- 1600- and you'd still struggle to hear it. Indeed the only time I hear it at all is for a brief second or two at post when it runs at full wack before the quiet fan setting kicks in.
A good bit of kit.
I recently upgraded from a AMD64 3500+ (which I ran with the stock cooler since it was quiet enough) to a duel core AMD 5000+. Even with cool'n'quiet enabled and 'quiet fan' set as in my boards bios (Asus M2NPV-VM) the stock cooler on the duel core while quiet at idle became quickly noticeable under any sort of load.
I replaced it with the Freezer 64 Pro which was fairly easy to fit and I have been very happy with it. Since the fans speed is controlled by the bios (via PWM) at low usage it spins at about 1000rpm and keeps my CPU at around 22C. Even with both cores fully loaded video encoding temps don't rise above 48c (with the stock cooler it was around 60-62c) and RPM rises to around 1500- 1600- and you'd still struggle to hear it. Indeed the only time I hear it at all is for a brief second or two at post when it runs at full wack before the quiet fan setting kicks in.
A good bit of kit.