78xx CPU heatsinks

my X9100 consisently idles around 68C-70C and i'm beginning to suspect that my heatsink is somewhat FUBARed from deeply ingrained ICD7 (from previous applications) that cannot seemingly be removed despite my best efforts.

it also seems like the part attaching to the northbridge (near locking screw 5)does not make full contact with the chipset; there is a slight incline caused where the heatsink is pushed down at one end due to locking screw 5 but the other side becomes slightly raised as a result.

the recommended ICD7 amount had been slapped on both the CPU and chipset.

looked on ebay for new heatsinks; also heard that Gateway apparently made different revisions of heatsinks. Was wondering if this were true:

this is what i currently have
GATEWAY P-63 P-68 P-78 FX CPU HEATSINK 60.4I202.001 - eBay (item 120588459685 end time Jul-02-10 17:17:11 PDT)

newer version?? If so, can anyone confirm that their 78xx series acutally has one of these installed. Design and screw positions look off.
GATEWAY 60.4I201.001 P-78 series HEATSINK ONLY - eBay (item 290421038869 end time Jul-31-10 14:31:21 PDT)

need something to provide me with adequate cooling for my crazy X9100 OCs - 3.7GHZ stable @ 1.362v

any help/advice/confirmation would be greatly appreciated.

cheers.

 

Try some Brasso on the heatsink. It should get that copper pinkish new again.

 

the copper is already "pinkish new" as you put it. It's the surrounding metal that still looks "dirty" (and rubs off black, probably due to the ingrained ICD7 from previous applications) that i am worried about.

i'm guessing this might be interefering with thermal conductivity especially on the part of the sink in contact with the northbridge chipset because there is no copper shim on that particular part.

 

Then use brasso there and see the effect.

 

bit of a daft question but:

are there any obvious signs that a heatsink has gone "bad"?

 

No not really. If your heat sink is "encrusted" with stuff though it might be time to actually take the machine apart and clean it really well. The gunked on stuff might be limiting its conductive properties (though it wouldnt be hurting it very much)

The M17x i have actually has paint on the heatsinks to make it match the rest of the black notebook and that isnt causing any real issues so i very much doubt the heat sink being a bit dirty would have any effect.

But honestly your computer was built to cool a 25watt CPU and your pumping a 44watt CPU to almost +30% voltage so its pretty amazing that it has been able to keep up at all

 

the trouble is that people with similar OCs (or even stock X9100) consisently report that they idle in the mid 30*Cs and here i am thinking ?!

gah.

well, I'll try frankensteining my heatsink with an additional copper shim for the NB chipset and stick on some pin fin VGA/RAM heatsinks to the copper piping.

 

Personally I'm of a mind to skip putting the "pin fins" on the piping since that would just encourage more heat to collect in the wrong place away from an exhaust fan. If it had any benefit some motherboard maker would've done it by now, and none have.

 

true true but short of swapping over CPUs, i'm willing to try anything right now.

got the pin fin heatsink idea from an M17x thread i browsed over a couple weeks ago (link eludes me right now ). Bascially, the guy plastered pretty much every free square inch of copper piping on his heatsink with the pin fins and saw a temperature reduction.

Granted the M17x vent design is open directly over the entirety of the heatsink (as opposed to the 7805u) but like i said, I'm willing to give it a shot.

Failing that, I'll be trying out a new heatsink (perhaps the locking screws on my current ones have messed up over time) and finally, I might have to resort to downgrading CPUs.

 

Sorry to revive an old post, that is the heat sink I have in my P7805. I think the one you have is the older version but also the one used on the Quad variations too. Since the TDP is higher for the Q9000 compared to the p8400 they use in the P7805 that HS you have already may be a better one.

I can tell you the X9100 I have at 3.6 with Prime 95 will overheat regularly at 3.6 GHz. I can run stable 3.7 as well with your settings for prime 95 but within a minute I'll be overheating. Idle at 3.7 is CPU 44C TZSx 51C........

 

I would ask, for those that done the copper mod to the northbridge. What thickness worked best. I too feel the screw tightening the northbridge side of the HS slifhtly offests the heatsink as it sits on the CPU............

 

I just got my P7811 and installed the shim so I can't tell you much but I used 11x11x.9 and idc7 on my northbridge. I also used AS thermal adhesive on the shim so I didn't have to apply double IDC7 every time I took off my heat-sync.

 

Thanks.............

 

i was rather wary of applying AS5 thermal adhesive for the copper shim mod; the last thing i want is for excess adhesive to ooze out the sides and start sticking things together that shouldnt be stuck together!

Opted to use an AS5 sandwich instead for the copper shim mod; far easier to clean than an ICD sandwich. Used ICD7 on CPU though.

 

I just applied the adhesive, then applied pressure and cleaned up any that came out the sides, applied more pressure and waited 5 minutes (it sets in 5 minutes). Then I put on the ICD7 and heatsink. But yeah I understand your worries which is why I followed the above steps.