Lapping the 2.4C IHS

[Liquid3D]

I decided to buy a pack of fine assorted wet/dry automotive grit papaer, and went to work. I lapped the IHS down to the copper, cleaning with rubbing alcohol frequently, and it looks so pretty. I also lapped the SLK900U, which is done to a mirror finish, but after awhile, the silver particles get in the micro-groves. Remember copper is actually a porus material. I lapped it down, and it looks even better then when I got it.

Perhaps the most surprising thing I found was the uneven surface of the Intel P4. The corners had significantly more material on them. I used a L-ruler to ensure the surface was flat and then wrapped the paper around an perfectly flat edge and went to work. Obviously this is critical, because you want a flat surface. But as I said it took quite a while for the corners to get down. This is bad, because with the outside edges contacting the Heatsink, there forms a pocket where hot air would become trapped. No good.

Prooof is in the sanding. Yesterday in the same Ambient temp (my air conditoned room) my overclocking temp was 45C to 49C at 3.6GHz (300FSB) today same ambeint temp, and OC conditions, and the temp's are now 38C, and haven't gone above 39C. That's 6C to 11C temp drop! Next I'll be removing the IHS all together. Intel uses thermal paste which is not of the highest quality, and of course they don't it spread thin and even as we would, but simply shoot a dollup of it on the core, and epoxy down the IHS. The hole is for gases to escape or the thing wouldn't adhere correctly. The latter is speculation. But they do use way too much paste, and as everyone know's this can become as much as a deficit, as a dissipation method. I shopuld have took pic's but i was too lazy. I'll take-em tomorrow, and add them to this post. The cip looks much better lapped.

[Major]

Good results ! I haven't tried lapping my P4's yet but I guess I should ! lol

[Liquid3D]

It's so easy, it's easy. When I first saw the copper i got nervous, until I remembered there's no way you could just lap through to the core. of course you'd see the thermal paste before you hit the core, but stranger things. I'm so silly. Anyway they must coat the IHS just so they can laser in the codes? I guess you wouldn't see it in copper, but i wonder if there's another reason it's coated? I think it's a coat of aluminum powder they put on it? Next I'm removing the IHS, I was going to do it, but decided to lap first. I wonder after removing the IHS if the SLK900U would be too heavy to place on there? Eeven with the more secure mounting system, which is much safer then a retention clip method, there may be shifting weight during installation which could crack the core.

I was concerned about static electricity, when lapping but cleaning with the alcohol frequently seemed to ameliorate any static build-up sinec the chip not only runs cooler, but runs period. Of course not having a wool carpet (or any) and not wearing wool is advisable as well. LOL

[Teus]

same here, silver paste got into the grooves of my SLK800. I'll give it a lap when I change some hardware. did you use your hands to sand it, or a sanding block?

[Creative]

Here are some pics of the 2.8 I had that the IHS came off when taking off the vapo evap head;







Unfortunantly the chip is dead due to the IC7 and vapo not mounting properly and not getting contact. I know it was the IC7 cos when I removed the evap, there was no contact with the AS paste on the core I had put there......I slapped it in the IS7 to see if still alive, and although it got beautifull contact.....the PC would not even post....ala dead cpu.....twas a shame cos this 2.8 was benching pifast and superpi at 4010mhz

Since this accident, I am a little hesitant to go ahead and freely remove the IHS by choice in fear of killing another cpu.....I wanted to try it with the 2.4 I have here that benches at 300fsb and maybe get some more fsb, but I dont want to risk such a good cpu.....

Cheers

[Peen]

Liquid3d , what was the finest grit sandpaper you used?i was thinking of lapping it first with 600grit then to 2000 grit that i have laying around. with that much of a drop in temps, im going to do what you did tommorow!

[Peen]

And is there anyway you can post a pic of it after you lapped it?
Sorry about your CPU creative, that would piss me off

And what can i polish it with to make it look like a mirror?

[STEvil]

hmm... shoudl we be lapping the core of the P4 like lapping the old Thunderbird cores too, now? hehe. 8-)

[Liquid3D]

Originally posted by Peen
Liquid3d , what was the finest grit sandpaper you used?i was thinking of lapping it first with 600grit then to 2000 grit that i have laying around. with that much of a drop in temps, im going to do what you did tommorow!

I started with 400, and went to 600. Do you really want to see pic's? It's a pain in the butt, but i could throw in the other 2.4C and take pic's for ya. Maybe I should just lap the other one I have as well? The second one has the warranty, as it's a boxed version, alhtough it doesn't seem to OC as stable? It'll do the same speeds (3696MHz), same voltage, (1.550V) but for some reason I got a lot more memory errors at high FSB when benchmarking it?

Whe you lap the CPU, be really careful how you hold it. Dont do it on the motherboard, because the copper powder might get into some fine circuitry cause a short. I held it really carefull as not to bend the pins, and sanded away cleaning with alcohol every few seconds or so.

By the way the Epox 4PCA3+ doen't have the 3:2 memory divider? Anyone know why? They don't have any BIOS updates either, except one which addresses one issue; crackling sound in the sound system?

[La1kr0diZ]

BTW, intel uses shin etsu thermal grease and thats considered to be the best one around. I`ve used several engeneering samples without heatspreaders - they get more hot tnen the ones with HS instaled - AFAIK its better to leave the hs on da chip.

[CCW]

Originally posted by Liquid3D


Whe you lap the CPU, be really careful how you hold it. Dont do it on the motherboard, because the copper powder might get into some fine circuitry cause a short. I held it really carefull as not to bend the pins, and sanded away cleaning with alcohol every few seconds or so.

When people lap Northbridge chipsets they have to do it on the board because it wont come off, they usally tape a bag around it over the board, you could do that if you want to leave the chip.

IMO, theres no point, doesnt take 2 seconds to take a chip out but just means no chance of damaging chip while holding it I spose.

Craig

[Peen]

nah, i did a search on google and saw some pic of ppl doing it, ima take mine out and go to 2000grit

[Peen]

im scared of getting copper in the little vent hole!?!

[Peen]

ok i lapped mine and got a temp drop of about 5-7c under load

[Liquid3D]

COOL isn't it! I mean literally. And so dam easy. Doesn't it look better. Of course say goodbye to the warranty, unless you remove the IHS first send it back and tell them the IHS fell off somewhere, hehe.

[Peen]

it look kinda cool from far away cause i didnt polish mine, but round copper section in the middle and a lil copper on the outside

I used my sisters makeup mirror , wet the back of the sand paper and stuck it on their for a flat surface and so the sand paper doesnt slip and slide. First i used 600 grit and got it down to the copper , then used the 2000 grit to perfect it. Right now im kinda upset cause it seems to be running about the same temps

[STEvil]

Did you go down far enough that the whole IHS had some kind of surface area taken off?

I should scan my old Celeron 366... but its at home right now 8-/

[Major]

OMG I beleive, I beleive !! can I have an Amen !!!!

Ok just go through lapping both the 2.4c and 3.0c, havn't had time to do anything other than set both rigs back up (actually 3 rigs) but my temps are unreal !!!! I can't beleive the difference it made ! just now starting to OC the P4C800 and 3.0c in promie. I'll be back !

[QuadDamage]

i did that too 2 days ago, but my temps went up... so i decided to reseat the evap and found the heatspreader moving around i was like wth? well, got rid of the heatspreader and enjoying direct block to core coolng

[Peen]

well on mine (and most others i bet) the middle is higher then the rest , cause it was the first part of the IHS that started to show the copper, i just went to when the copper area in the middle was about 2-3 inches

[Major]

Both the 2.4c and 3.0c that I have where lower in the center than the edges. On the 2.4c it was quite a bit lower. The 3.0c wasn't that far off from being flat.

[Peen]

My cpu is still reaching nearly 70c according to the winbond hardware doc on my IS7 . didnt really help , geuss i need better cooling

[Major]

Peen, one thing that you have to be careful of is using too much thermal compound especially when the two surfaces are free from pits and are truely flat. It should be very, very thin almost to the point of being able to see through it. Just a light hazing. You might already be appling it corectly, just wanted to point this out as a posible cause for your temps.

[Peen]

yeah, mines so thin that i could barely get it all spread out across the IHS , im guessing its cause the heatsink has very little actual HEATSINK lol

Edit: Major are you using AS3?

[Peen]

wheres the cheapest place i can get a SLK900u?
ok i figured out a better way to lap the IHS maybe, using 600 grit wet sandpaper and 2000grit wet sand paper.

1: Get a mirror and place on floor
2: Get the 600grit sand paper wet both front and back
3: Put 600 grit sand paper on mirror and water will help it not move
4: Slide you P4 across in a figure 8 until you see what looks like mud on the sandpaper (Actually copper)
5: Take sand paper and give it a good washing
6: Put sandpaper back on mirror and keep doing all this till ALL the IHS apears to look copper, and then do some figure 8's around the paper some more to make sure its PERFECTLY flat
7:Clean off CPU with alchohol
8: Now do this again with the 2000grit for quite some time to make sure all the groves from the 600 grit is gone, AND make sure that you clean the sandpaper regularly at least with water

I wouldnt worry TOO much about static electricity killing your CPU as i was doing this on shaggy carpet and no obeying any of the rules.

So basically the first time i did it, i didnt do a very good job and second time is doing about 2c better with a full load of about 64c (Which still sucks!)

Anyone who wants to OC their P4 more id say you HAVE to do this!