Delta BL 60mm beats Tt SF2 80mm on SLK-800!

My Specs:
P3-s 1.4 @ 1.65ghz vcore 1.525
SLK-800
Abit ST6
Vantec Stealth 520w
VisionTek GF4 Ti4400 @ 317/630
Turtle Beach Santa Cruz
Ahanix Platinum XP case
1x Tt Smart Fan II Exahust
1x Tt Smart Fan II Intake
AOC System Blower
Sunbeam Blue/Green Dual Cathode


Delta BL 60mm (6800 rpm) - 39c load
Tt Smart Fan II (5100 rpm) - 42c load

WTF? How the hell can the 60mm beat the 80mm when it's putting out less cfm?
The noise level is about the same but I find the delta to be more annoying cuz of the high pitched whine.

Is there a high cfm 70mm fan out there to buy? I'd love to test with that as well.

Very interesting...

There are a few differences/variables that I can think of...

Ambient temps?

different airflow characteristics?

differences in static pressure performance?

Smaller central hub on the delta?

When switching the fans around, did you remount the sink or just remove the fans with the sink still attached?

I'd be curious to see a TMD fan on one of those.

JasonKosi said:

Very interesting...

There are a few differences/variables that I can think of...

Ambient temps?

different airflow characteristics?

differences in static pressure performance?

Smaller central hub on the delta?

When switching the fans around, did you remount the sink or just remove the fans with the sink still attached?

I'd be curious to see a TMD fan on one of those.

Click to expand...

Didn't remount the sink. I just switched the fans and run P95 for an hour. Tried switching twice, and get the same results, the 60mm beat the 80mm both times by 3c.
Yeah, I definately would want to try a high cfm 70mm, less noise than the 60mm, and possibly better performance than the 80mm.

I'm currently writing a formula for cfm/size ratio. My explanation of that is that the 60mm has to put more cfm through a smaller space, whereas the 80mm fan has the air more spread out, and the 80mm has more air flowing out of the fins than the 60mm.

-PC

This would make an interesting review. Test a whole load of fans with the SLK800 and find out which one is the end-all be-all.

Unless someone already did this

Just found this, http://www.a1-electronics.co.uk/Heatsinks_Cases/Heatsinks3/Thermright_SLK-800_pg2.shtml

This review shows the 60mm 45cfm delta beating out the 68cfm 80mm delta and just a bit higher than the 80cfm 80mm delta. I have seen other reviews that tested the 50cfm 60mm fan and that beat the 84cfm tornado by a bit. I have only seen two or three reviews with people testing out alot of fans on the slk-800. I started a thread a while ago on this very subject and it think it could help us understand why the slk-800 performs better with the smaller fan. http://forum.oc-forums.com/vb/showthread.php?s=&threadid=143560

I hope this helps, as there isnt alot of info out where people test out 60mm fans or such on this heatsink sofar.

Perhaps there is a problem with turbulence with the larger CFM fans? It maybe not flowing as well through the heatsink as a lower CFM fan. Maybe you should trying lowering the speed of the 80mm fan and see if temps. decrease. Just a thought.

Mostly for the 80mm fans it looks like alot of cfm is wasted. Alot the flow from the 80mm fan that hangs over the slk-800 doesnt help performance, also the high speed 60mm fans being more effeceint as all the air from a 60mm fan hits the heatsink fins. I have been seeing that the slk-800 really likes the 38mm wide/air vane type fans. The tmd 70mm fans and other fans that arnt either spaced off the heatsink so the fan blades dont shroud the airflow against the copper thin fins and thus cause a pretty good pressure drop. I would like to see somthing like Hoot's 176 cfm blower connected to this sink and see how much better it could perform and see if it is near its max performance right now.