Zalman 7700CU Mod with FM121 Fan

[Grimmy]

I was bored, so I brought the SilverStone FM121 case fan to replace the Zalman 120mm fan. Not sure if anyone else posted something to this.

Note that you will have to break the fan bracket casing to get the fan out.

So, down to the basic's. The difference is CFM between the fans, so 7700 orginal fan puts out around 30 CFM, while the FM121 puts out around 110 CFM.

To start out with the pictures, this is what they look like side by side:

Taking the fan off is simple. 1 screw on each side, will let loose the fan bracket to the HS:

Now underneath the fan, there are 2 screws holding that bracket on. I did make a paper template to figure out placing/drilling new screw holes.:

Now here is where I go wrong. I did end up putting the bracket on with the orginal hardware. Turns out, that when you place it in the HS, you will run into basically 2 problems. The bracket needs to be lined up at the very bottom hole.

Problem 1, the fan will not turn because of the clearance. I thought I could get around but pushing the bracket up, which did give clearance for the fan to turn, though now the bracket tension is too great for the retention bracket on the MB.

Sooooo, I took measurements, which turns out it needs to be 1/2 cm thick (hard to hold the camera, and ruler :lol:

I then thought of a lazy way to take up space between the FM121 fan by taping a big thick spacer. I had to find other screws to attach it back onto the bracket:

So now it fits, spins, and these are the finishing pictures:

The only immediate difference, was the MB chipset temp. It was running about 2C cooler. :lol:

I need to reburn in my chip again for AS5 to cure. There is a difference in noise when you push the fan at full speed. Which is another thing. This fan is rated to run 2400 RPM. My MB only registers around 2280 RPM max.

The Zalman fan was rated for 2000 RPM. My MB only would report around 1965 max RPM.

Later on I might post the CPU temps if its a big change. For now, its about the same But like I said, the chipset is running cooler, since more air is being pushed onto the MB.

Thought this was something interesting to do/find out. So if you ever buy this HSF, at least you know that you can use another case fan, if you orginal went out for some reason.

 

[trixst4r]

i thought that you would get ~5 on those chipsets at least with a tornado brewing up at the proccesor 8)

cool mod

 

[Grimmy]

Ah.. back pressure. That makes sense.

I think I will notice the temp drop when my room is back to 70F. Seems 80+F has too much adverse effect to make much of a difference on the CPU.

 

[Grimmy]

Got some testing done, since it got cool in my room.

Unfortunately, my OC to 3Ghz isn't stable, but it is the only comparison I have recorded.

So, this is what I basically came up with:

Room temp - 72F (22C) - MB Chipset - 28/29C

Zalman original fan (AS5) P4-2.66@3.0:

Idle - 43C
Load - 52-53C

Zalman Mod (AS5) P4-2.8:

Idle - 38C
Load - 49C - @ 2020 RPM or 2250 Max RPM.
Load - 54-55C @ 850 RPM

Seems as though once the RPM is around or above 1900+ RPM, it didn't make much of a difference, execpt more noise when cranking it up.

I may mess around more to see if I can better results later.

 

[ANIA_fanboy]

Very nice mod.

I have the same cooler and thought that there could a better fan for it (not that I was not happy with it as it was).

However, my lack of imagination and inability to come up with ANY original ideas hinders me.

Thats for the idea.

I'll keep it as my own