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AC Freezer4 fun - LGA775 fitment and Intel retail frameless 92mm PWM fan mod

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larva

Inactive Moderator
Joined
Jul 12, 2002
I thought that my recent move to prescott signaled the death of quiet computing at my house. To my surprise, the heat produced at 4GHz is easily dealt with, and it doesn't take loud fans. I fit my existing S478 AC Freezer4 to my Abit AG8-V LGA775 mb using the Thermalright LGA775 RM adaptor, and started playing with 92mm fans. I'm running a P4 506 (2.66GHz/533fsb Prescott w/EM64T) at 200fsb for 4GHz on 1.48V. While I don't know that the stock 77mm 2200rpm frameless fan wouldn't have sufficed; I was in a mood to experiment and 92x25mm box fans fit up very easily.

I tried NMB, Sunon, Sanyo, and Panaflo 92x25mm box fans that turned 2450-3300rpm max, but there is a clear noise/performance tradeoff with them. The NMB, Sanyo, and Panaflos are very effective, but can develop a whine if turned fast enough. The Sunon was the opposite, very quiet with lesser performance overall, even with 3000+rpm.

92mm box-fan perfomance tends to be high, but noise is an issue. The effective box fans produced idle temps below 35C and load temps around 52C turning 1950rpm at idle and 2450rpm at full load. They aren't terribly silent running 2450rpm, and the voltage scheme fan control required by their 3-pin configuration can't back off the idle speed any more than 1950rpm.

I was really impressed by how good the stock Nidec frameless 92mm fan on the retail Intel LGA775 heatsink that came with my P4 506 is. Its PWM control is desirable and it makes only a modest whine even WFO and cools very nearly as well as the most agressive of the box fans. I decided it had to be fitted to my Freezer4, creating a quasi Freezer Pro in the process. A small pair of sharp Craftsman wire cutters was used to trim the thin aluminum fins as required to accept the attachment clips of the Intel fan. In the end it wasn't that hard, and the next on will be pretty, too :)

The Intel fan is a Nidec product rated at .42A at 12V. It turns about 3500rpm WFO, and makes impressively little noise doing so. It fits flush to the retail heatsink, no box-fan gap. Running this fan on my Freezer4 on the AG8-V Abit in my sig machine yields great results. The PWM scheme fan control supported by the 4-pin Intel/Nidec fan can back the fan speed all the way off to ~1000rpm at idle, well below its point of audibility. Doing so results in idle temps of ~45C. I can increase the idle speed to ~1600rpm without hearing the fan over the rest of the machine and the idle temps drop to 38-39C.

Load speed I determine by the action of the Abit's PWM fan controller ciruit. You define upper and lower temperatures to guide its actions, and I set the upper bound to 55C and told it to run the fan WFO at that point. Doing so results in a loaded temp in my rig of 53C, and requires ~2200rpm to do so. You can just barely hear the fan at all at WFO, and at anything less it is inaudible.

When fitted to the aluminum retail heatsink this same fan turned 2500rpm at idle and 3500rpm at load--clearly audible. And in return you only got ~50C idle temps and a pause-giving 68C at full load. Compare this to the Freezer 4's performance, which yields 11C better idle and 16C better load temp while only spinning the fan at 1600-2200rpm! This gives you an idea of just how much more effective a good heatpipe design is than a simple aluminum sink.

All in all, the Intel retail fan has the best performance/noise ratio of any 92mm class unit I tried. And it's super quality, and I already owned it. The 4-pin configuration is terrific for the degree of fan speed control it affords with the fan controll I also already own in the bios of my Abit LGA mb. Combine it with my (you guessed it, already owned) Freezer 4 with the $5 dollar TR adaptor and the Prescott is cheaper and faster than the northwood it replaced, quieter at idle and no louder at load. Better than expected, and nearly free to me :D
 

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OP
larva

larva

Inactive Moderator
Joined
Jul 12, 2002
Freezer 4 installed in AG8-V Abit LGA system via the Thermalright LGA775 RM adaptor:
 

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speed bump

Member
Joined
May 11, 2004
Location
Montana tech Butte mt.
Nice those are nice fans even on the stock coolers they do well.

I dont really like the frame less design very much becuase I bumped another fan into mine and took out a fan blade once but it does make it very quiet.

BTW Artic cooling also makes frameless fans like the stock intel one.
 
OP
larva

larva

Inactive Moderator
Joined
Jul 12, 2002
Yeah, I've created my own ghetto Freezer Pro, albeit with 2 pipes instead of three. AC rates the original Freezer to 130W output and the Freezer Pro to 200W, so I guess a 4GHz prescott doesn't exceed 130W as I can't see any downside to my orignal Freezer's performance.

Based on what I've found with modding the original Freezer, I'm guessing the Freezer Pro is mighty effective. But I think the Intel-spec Nidec is a lot more durable than the ceramic bearing AC fans, so I'm inclined to use it even though a Freezer Pro only commands $28 from directron. It's hard to worry with spending more when these things work so well.