SK-6 Experience

[Texun]

Noticed a ton of posters in this forum are using the SK6 so I felt the urge to add my recent experience with the SK6 to this thread.

Have been using the Volcano Cu6 for about a month with temps at about 36'ish idle and sometimes 50C loaded. Wanted the super-duper SK6 so placed my order and got it this week. The surface looked pretty good at first glance, but when I applied the AS-II to the cpu and added the HS I noticed that it didn't even contact the AS-II. Checked the surface with a straight edge and found it was concave. Not by much to the naked eye, but it doesn't take much. Out I go to get sand paper and start lapping. Lapped it on a flat surface and buffed it out. I installed it again and it made contact this time, but not 100% so I worked on it again. After an evening of lapping I gave it a test. Fired it up and by the time Windows booted, the cpu was at 100F and still climbing about 1 degree every 5 seconds or so. Yes, I tried installing it both ways.

Used 320-400-800 and 1000 grit paper I got at Pep Boys Auto. Probably should have started out below 320 though... Pulled the fishing sinker off and lapped my 1 month old Cu6 to get rid of those d^&$% swirl marks and reapplied the AS-II. It came out nice and flat and polished up well. Sitting here now with the cpu level at 35C \ 98F and a room temp of 73F.

No flames please, but for those who like the SK6 I say congratulations on a well cooled system. The design is great. However, there is no way in hell I'm going to mess with it again until I go fishing. I should have sent it back. But for now I can live with my stock-clock XP1700 on the web at 35C. Ran Operation Flashpoint with all knobs at 11 for about an hour and it never went above 46C. I reached my goal of having it stay below 50C, and I've come to the conclusion that even lapping a "cheap" heat sink can provide decent results with an XP1700 under load.

R

 

[PhiI2e]

Hmmm I get 37 idle right now and 41c full load with an ambient of 32c. I have a non-lapped SK6 and an xp1600+. Weird man

 

[Rahminator]

My SK-6 with 30CFM delta makes my XP 1600 1.4 @ 1.56 idle at 42*C and full load at 52*C with cpuburn.

 

[PhiI2e]

And this is off my lcd thermister which is on the side of my core. How many fans you got and what case you have?

 

[Emo]

I saw a small improvement when I mildly lapped the heatsink. I didn't use sandpaper but a little auto polish (safe for chrome, aluminum and copper) dabbed on a piece of clean cloth. To make sure that I was getting an even surface, I used a piece of 1" square glass as a backing for the cloth. It took about 10-15min to bring a mirror-like shine, and then I needed to apply very little silver grease. After all was said and done, I was rewarded with a degree or two of lower temperatures. BTW, I swapped the noisy Delta 38cfm for the quieter 4500rpm 32cfm fan from the Volcano 5.

 

[Texun]

PhiI2e

Using a Fong-Kai 602 which can be seen HERE. Bought it without a PS and added my own Enlight with the vents over the cpu to help suck hot air away from the chip. The case also came with a ducted 80mm rear fan. I added a Sunon 80mm fant in the front. Add the GF2-Pro AGP card and the HS-fan and that makes a total of 5 counting the PS. Haven't figured it out. Maybe I just got a junk SK6. I do know that when I locked the SK6 down on top of the cpu and then pulled it off, I had a small smudge mark of AS-II on the HS. I would estimate the total surface contact to be about a third of the chip. Placed the Cu6 on it and it was 100% covered.

Thanks,

R

 

[Texun]

Emo

The fan from the Volcano 5 is exactly what I was using. I had the V5 in the closet but went with the 6Cu because of the copper plug in the bottom. Why Thermaltake machined the swirls on the bottom of the copper plug is beyond me. It dropped 1-2 degrees after lapping it off.

Thanks,
R

 

[Blain]

"The surface looked pretty good at first glance, but when I applied the AS-II to the cpu and added the HS I noticed that it didn't even contact the AS-II. Checked the surface with a straight edge and found it was concave. Not by much to the naked eye, but it doesn't take much. Out I go to get sand paper and start lapping. Lapped it on a flat surface and buffed it out."

If you lapped it flat, then it should be as flat as it can get. If you also lapped your other HS flat, it should also be as flat as it can get.
With both HS flat, it should only come down to which design/material/fan was the better contender.

If your SK6 isn't making 100% contact after you lapped it... I'd say go back to the 320 and start over. Was your "flat surface" thick glass, or something else?

 

[WarCon]

If the clip is on backwards, you can end up with a partial contact only which usually cooks the chip. You might check and just make sure the part that touches is right over the core.

 

[Texun]

Oky, WarCon and Blain;

Help me out here... I am 99.99999% sure I tried the clip every way possible. The HS still only made contact with about one third of the chip, as indicated by the amount of AS on the sink after it was removed. There was a thin film of AS on the HS, and in that thin film was a smudge that looked, dare I say, "pinched" as it came in contact with a leading edge of the chip when it was pressed down.

If I were to lay it flat on the cpu and press down, it still only marked about a third of the chip. Did the same thing with the Tt-Cu and it covered 100%... clip or no clip (for testing of course).

What the hell am I missing? :frown:

Thanks!
R

 

[Blain]

It sounds to me that the clip isn't making contact in the right spot. Try this...
* Remove the heatsink (whichever one is mounted).
* Clean the CPU slug off, in order to see it well.
* Fasten the SK6 clip in place, without the heatsink (you shouldn't have to fasten it to both sides to see where the problem is).
* Look to see where the clip WOULD be pressing IF the heatsink were installed. That should tell you if the clip would be pressing down directly over the CPU slug. You can try it both ways just to be sure which is correct.

If (positioned correctly), the clip would be pressing down "off-center" of the slug... do a little bending, to bring it directly over the slug. Just remember not to bend the "spring" out of the clip. It still has to apply enough force when the heatsink is installed to secure it.
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The way I see it, there can be very limited options for what's causing your contact problem.
1. Clip not applying pressure at the correct spot.
2. The rubber supports on one side of the CPU slightly higher than the others (not likely, since the Volcano seats fine.
3. The slug not even with the rest of the CPU surface. Once again, if the Volcano seats fine, this probably isn't the problem.
4. The SK6 is all screwed up and not flat at all. This is probably not the case since you've lapped it.

While you have the heatsink off, you might try just pulling the CPU out and re-seating it. Just to make sure it's seated well in the socket.